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  • Intercellular Adhesion Molecule 1 Antibody-Mediated Mesoporous Drug Delivery System for Targeted Treatment of Triple-Negative Breast Cancer
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-10
    Mengru Wang, Wanhua Liu, Yanqiu Zhang, Meng Dang, Yunlei Zhang, Jun Tao, Kun Chen, Xin Peng, Zhaogang Teng

    The development of effective targeted therapies for triple negative breast cancer (TNBC) remains a challenge. This targeted drug delivery system used a near-infrared fluorescence dye cyanine 5.5 (Cy5.5) and an ICAM-1 antibody on thioether-bridged periodic mesoporous organosilica nanoparticles (PMOs). The ICAM-1 antibody and cyanine 5.5-engineered PMOs (PMO-Cy5.5-ICAM) offer excellent in vivo and in vitro biocompatibility. The PMO-Cy5.5-ICAM shows a loading capacity up to 400 mg/g of doxorubicin (DOX). The drug release profile of the DOX-loaded targeted delivery system (DOX@PMO-Cy5.5-ICAM) is pH-sensitive. Confocal microscopy showed that the PMO-Cy5.5-ICAM efficiently targets and enters TNBC cells. In in vivo experiments, the DOX@PMO-Cy5.5-ICAM accumulates more in TNBCs than in the control groups and exhibits better therapeutic effects on TNBC; thus, it is a promising treatment strategy for TNBC.

    更新日期:2018-12-10
  • Preparation of TiO2 Microspheres with Tunable Pore and Chamber Size for Fast Gaseous Diffusion in Photoreduction of CO2 under Simulated Sunlight
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-07
    Hongju Wang, Dapeng Wu, Wenpeng Wu, Danqi Wang, Zhiyong Gao, Fang Xu, Kun Cao, Kai Jiang

    TiO2 microsphere with tunable pore and chamber size are prepared by a simple solventhermal method and used as catalyst for the photocatalytic CO2 reduction. It is found that the hollow microsphere with relative lower surface area of 73.8 m2g-1 exhibits increased pore size of 18.1 nm and cavity structure, leading to higher CO2 diffusion coefficient of 5.40×10-5 cm2s-1 compared with the solid and yolk/shell microspheres. Therefore, the hollow microsphere possesses more accessible sites for CO2 adsorption, which finally gives rise to the enhanced CO production rate of 10.9±0.7 μmolg-1h-1 under simulated sunlight, which is respectively 1.6 and 1.4 times higher than that of solid and yolk/shell microspheres. Electron dynamic study further demonstrates that hollow microsphere shows the highest photocurrent density and the lowest charge recombination among three microspheres structure, which is attributed to the swift CO2 diffusion providing fresh CO2 molecules to rapidly scavenge the photo-generated electrons and finally leading to the excellence catalytic reduction performances. This method could be adopted as a general strategy to prepare high performance TiO2 catalysts with desirable structural qualities for the photocatalytic CO2 reduction under nature sunlight.

    更新日期:2018-12-08
  • A general strategy to fabricate soft magnetic CuFe2O4@SiO2 nanofibrous membranes as efficient and recyclable Fenton-like catalysts
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-08
    Feihao Shi, Haoru Shan, Di Li, Xia Yin, Jianyong Yu, Bin Ding

    Fenton or Fenton-like technique, as one of the advanced oxidation processes, plays a significant role in the removal of non-easily degradable organic pollutants; however, most of such catalysts are fragile with poor structural integrity under large deformation, thereby restricting their wide applications. Herein, soft copper ferrite nanostructures functionalized silica nanofibrous membranes (CuFe2O4@SNM) were fabricated through a novel strategy with the combination of in-situ dopamine polymerization, ion adsorption, and cohesive precipitation method. Benefiting from the high metallic ion adsorption capacity of polydopamine together with the rapid co-precipitation of adsorbed ions on fiber surface in alkaline solution, the membranes possessed homogenously distributed nanostructured CuFe2O4, large specific surface area, and high pore volume, which are a benefit for the improvement of Fenton-like catalytic activity towards organic pollutants decomposition. The resultant soft CuFe2O4@SNM provided favorable catalytic performance towards organic pollutants with a relatively high degradation degree of 96% in 20 min, a fast removal rate of 0.148 min-1, and outstanding recyclability. The successful preparation of such fascinating ceramic nanofibrous membranes would provide a reference for further exploitation of new type Fenton or Fenton-like catalysts with outstanding softness towards wastewater purification.

    更新日期:2018-12-08
  • Crystallization and properties of poly(ethylene terephthalate)/layered double hydroxide nanocomposites
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-08
    Siyuan Dong, Yingqi Jia, Xiaozhi Xu, Jianeng Luo, Jingbin Han, Xiaoli Sun

    Poly(ethylene terephthalate) (PET) generally suffers from low crystallization rate and long molding duration, which as a result limit its application as engineering plastics. To overcome these drawbacks, series of PET/layered double hydroxide (LDH) nanocomposites were prepared by a solution blending process. The effect of metal composition (MgAl and CaAl) and organo-modification (stearic acid interclated) for LDH fillers on the crystallization behavior of the nanocomposites was investigated. It was revealed that, compared with PET/CaAl-LDH, the PET/MgAl-LDH nanocomposite exhibits a higher crystallization temperature and faster crystallization rate, which is associated with the superior nucleation ability of MgAl-LDH. The nucleation mechanism of PET induced by LDHs was explored by means of Avrami equation and theory of Hoffman-Lauritzen, pointing out that the incorporation of LDHs reduce the free energy of nucleation and the fold surface free energy of PET. In order to improve the compatibility between LDH and PET, stearic acid (SA) intercalated MgAl-LDH was prepared and filled into PET matrix. The resultant PET/MgAl-LDH-SA shows a further enhanced crystallization temperature and accelerated crystallization rate, in comparison with PET/MgAl-LDH nanocomposites. In addition, the thermal stability, gas barrier and mechanical properties of PET/LDH composites were improved upon incorporation of LDH fillers.

    更新日期:2018-12-08
  • Hierarchically porous and heteroatom self-doped graphitic biomass carbon for supercapacitors
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-08
    Lijie Hou, Zhongai Hu, Xiaotong Wang, Lulu Qiang, Yi Zhou, Liwen Lv, Shanshan Li

    Here we report a simple, low-cost and environment friendly method, in which Black locust seed dregs and potassium ferrate (K2FeO4) are used as starting raw materials and activation agent. The hierarchically porous carbons (BDPC) with high special surface area and abundant mesopores (SBET=2010.1 m2 g-1 and Vmeso=1.457 cm3 g-1) are obtained through hydrothermal treatment and chemical activation. The BDPC electrode exhibits excellent electrochemical performances by virtue of unique architecture and heteroatoms pseudocapacitance contribution. In the three-electrode system, the optimized carbon material (BDPC-2) achieves a high specific capacitance of 333 F g-1 at 1 A g-1 and displays the high rate capability (81.1% capacitance retention at 100 A g-1) in 6 M KOH electrolyte. The symmetric supercapacitor based BDPC-2 exhibits energy density as high as 26.2 Wh kg-1 (at a power density of 0.79 kW kg-1) and excellent long-term cycling stability (only 8% decrease after 10000 cycles) in 6 M KOH.

    更新日期:2018-12-08
  • Irreversible hardening of a colloidal gel under shear: the smart response of natural rubber latex gels
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-08
    Guilherme de Oliveira Reis, Thomas Gibaud, Brice Saint-Michel, Sébastien Manneville, Mathieu Leocmach, Laurent Vaysse, Frédéric Bonfils, Christian Sanchez, Paul Menut

    Natural rubber is obtained by processing natural rubber latex, a liquid colloidal suspension that rapidly gels after exudation from the tree. We prepared such gels by acidification, in a large range of particle volume fractions, and investigated their rheological properties. We show that natural rubber latex gels exhibit a unique behavior of irreversible strain hardening: when subjected to a large enough strain, the elastic modulus increases irreversibly. Hardening proceeds over a large range of deformations in such a way that the material maintains an elastic modulus close to, or slightly higher than the imposed shear stress. Local displacements inside the gel are investigated by ultrasound imaging coupled to oscillatory rheometry, together with a Fourier decomposition of the oscillatory response of the material during hardening. Our observations suggest that hardening is associated with irreversible local rearrangements of the fractal structure, which occur homogeneously throughout the sample.

    更新日期:2018-12-08
  • Noble metal nanoparticle-functionalized Zr-metal organic frameworks with excellent photocatalytic performance
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-06
    Jianhao Qiu, Xingguang Zhang, Kailuo Xie, Xiong-Fei Zhang, Yi Feng, Mingmin Jia, Jianfeng Yao

    Noble metal nanoparticles (NPs) functionalized MOFs are attractive materials for photocatalytic reactions, and outstanding catalytic performances can be expected, especially when they have intrinsically matched crystal faces between metals and MOFs. This study discovered that the photocatalytic oxidation of aromatic alcohols to aldehydes was enhanced over Au/UiO-66-NH2 or Au/UiO-66 but suppressed over Pt loaded counterparts, whereas the reduction of Cr(VI) was boosted over both two catalysts. In reactions, the conversion of benzyl alcohol was 17.1% over UiO-66-NH2 and 7.6% over UiO-66, and an enhanced conversion was obtained over Au/UiO-66-NH2 (30.5%) and Au/UiO-66 (24.1%). However, the conversion was decreased over Pt/UiO-66-NH2 (9.3%) and Pt/UiO-66 (< 1%). Experimental results revealed strong correlations between Zr-MOFs and loaded metal NPs, as Zr centers promoted the formation of Pt(200) planes that suppressed the production of ·O2– intermediates to oxidize aromatic alcohols, whereas Pt(200) exhibited no effect on the Cr(VI) reduction triggered by photo-induced electrons. The findings in this study on constructing noble metal NPs functionalized Zr-MOFs catalysts with specially-matched crystal structures and on distinguishing photocatalytic mechanisms on oxidation of alcohols and reduction of Cr(VI) would provide valuable information for designer (photo)catalysts based on MOFs and their applications in such as catalysis and environmental remediation.

    更新日期:2018-12-07
  • A bifunctional conjugated polyelectrolyte for the interfacial engineering of polymer solar cells
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-07
    Francesco Carulli, Guido Scavia, Elisa Lassi, Mariacecilia Pasini, Francesco Galeotti, Sergio Brovelli, Umberto Giovanella, Silvia Luzzati

    In this work a novel combination of side chain functionalities, alkyl-phosphonate (EP) and alkyl-ammonium bromide (NBr) groups, on a polyfluorene backbone (PF-NBr-EP) was studied as cathode interfacial material (CIM) in polymer-based solar cells. The devices were made with a conventional geometry, with PTB7:PC71 BM as active layer and aluminum as metal electrode. The CIM showed good solubility in ethanol and film forming ability onto the active layer so that its deposition could be finely tuned. The interface engineering imparted by this CIM was assessed and discussed through kelvin probe force microscopy (KPFM), impedance spectroscopy, charge recombination and electron transport characterizations. To discriminate between the interfacial modifications imparted by the interlayer and its solvent, we included in this study a surface ethanol treated device. In the optimized conditions an average power conversion efficiency of 7.24% was obtained, which is about 60% higher when compared to devices made with bare Al and 26% when compared to devices made with a standard calcium/aluminum cathode. Besides performances, some insights about the devices shelf life stability are also presented. A good persistency through aging was found for the cathode interfacial engineering capabilities of PF-NBr-EP.

    更新日期:2018-12-07
  • Janus multi-responsive superparamagnetic nanoparticles functionalized with two on-demand and independently cleavable ligands for Actinide separation
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-07
    Kunzhou Wang, Bin Wang, Huailiang Li, Xianguo Tuo, Kun Xiong, Minhao Yan, Jérémie Courtois

    HypothesisNanoparticles functionalized with ligands which can on-demand and remotely be detached have recently attracted interest as stimuli-responsive materials. Research is now focused on multi-responsive systems, with applications in environmental science and biomedicine. The possibility to covalently couple two different ligands on a single nanoparticles, and to release them independently is investigated. This concept of nanoparticles functionalized with dual on-demand cleavable ligands is exploited in ground water decontamination and radionuclides separation. Efficient separation of contaminants in a single step is expected, simplifying partitioning process and decreasing generation of secondary waste by nuclear industry.ExperimentsSub-10 nm Janus superparamagnetic nanoparticles are functionalized by click-chemistry (thiol and Diels-Alder) with two different Actinide-specific chelators. The reversible covalent bonds allow to detach chelators independently by either pH- or thermo-stimulation. The nanoparticles decorated with diethylenetriamine-pentaacetic acid (DTPA) and [(2-furan-2-yl-2-hydroxy-ethylcarbamoyl)-methoxy]-acetic acid (FHECMAA) are incubated with UO22+ and La3+ (as substitute for Pu3+) at pH = 3 and 7 before chelator-metal complexes are released. Metal contents are measured to determine separation efficiency.FindingsChelators can be detached from Janus nanoparticles with perfect selectivity. The nanoparticles are highly efficient for extraction of metals in acidic medium and show good ability for separation of U and La at neutral pH.

    更新日期:2018-12-07
  • One-pot synthesis of hyper-cross-linked polymers chemically modified with pyrrole, furan, and thiophene for phenol adsorption from aqueous solution
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-06
    Xiaomei Wang, Han Ou, Jianhan Huang

    Pyrrole, furan, and thiophene modified hyper-cross-linked polymers (HCPs) were prepared in one-pot method by two successive Friedel-Crafts reactions, and they were assessed by phenol adsorption from aqueous solution. The results indicated that the three chemically modified polymers had lower Brunauer-Emmett-Teller surface area and pore volume than the common HCPs, while the phenol adsorption on the pyrrole and thiophene modified polymers was relatively enhanced due to the introduction of the heteroatoms on the surface. Notably, the enthalpy changes of HCP-Py, HCP-Fu, and HCP-Th were greater than the HCPs, and the introduced heteroatoms provide greater interaction with phenol through dipole-dipole interaction. More importantly, the kinetic adsorption revealed that the required equilibrium time on the three chemically modified polymers (about 45 min) was shorter than the HCPs (about 75 min), and the pseudo-second-order rate equation described the kinetic data very well. The micropore diffusion model was suitable for characterizing the adsorption on the HCPs, but it could not account for the kinetic data on the chemically modified polymers.

    更新日期:2018-12-06
  • A one-pot strategy for preparation of high-strength carboxymethyl xylan-g-poly(acrylic acid) hydrogels with shape memory property
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-06
    Xinxin Liu, Minmin Chang, Bei He, Ling Meng, Xiaohui Wang, Runcang Sun, Junli Ren, Fangong Kong

    High strength hydrogels open new possibilities in the fields of bioengineering and biomedical. In this paper, a highly efficient one-pot strategy was developed to prepare carboxymethyl xylan-g-poly (acrylic acid) (CMX-g-PAA) hydrogels with high compression strength, high elongation and high elasticity by using the metal coordination and the reinforcement of hydroxylate multi-walled carbon nanotubes (HCNTs). Prepared hydrogels were characterized by means of FTIR, XRD, SEM, rheological measurements as well as their swelling and mechanical properties. Results showed that the Fe3+-carboxyl coordination and HCNTs imparted hydrogels with high strength and good rapid recovery properties, in which the maximum high compressive strength and elongation at break were achieved to 10.4 MPa and 1032%, and the shape of hydrogels almost returned to the original shape after the external force was removed after 30 cycles of compression. These hydrogels also exhibited Fe3+-triggered shape memory properties. Therefore, as-prepared hydrogels possessing high strength, rapid recovery and shape memory properties, could broaden access for application in intelligent toys, electronic skin, biosensing, and tissue engineering.

    更新日期:2018-12-06
  • Corrosion inhibition of X65 steel in sulfuric acid by two food flavorants 2-isobutylthiazole and 1-(1,3-Thiazol-2-yl) ethanone as the green environmental corrosion inhibitors: Combination of experimental and theoretical researches
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-06
    Bochuan Tan, Shengtao Zhang, Hongyan Liu, Yuwan Guo, Yujie Qiang, Wenpo Li, Lei Guo, Chunliu Xu, Shijin Chen

    Food flavors of 2-isobutylthiazole (ITT) and 1-(1,3-Thiazol-2-yl)ethanone (TEO) for the corrosion inhibition of X65 steel in H2SO4 were studied by electrochemical methods, atomic force microscopy (AFM), scanning electron microscopy (SEM) and theoretical calculations. Electrochemical experiments show that ITT and TEO can effectively inhibit the corrosion of cathode and anode of X65 steel, and they are mixed-type corrosion inhibitors. Surface topography analysis (SEM and AFM) also visually demonstrate that ITT and TEO form an effective barrier film on the X65 steel surface to isolate the corrosive medium. Theoretical calculations profoundly explain the inhibition mechanism of ITT and TEO at the molecular level. In addition, the adsorption behavior of ITT and TEO on the surface of X65 steel is consistent with Langmuir isotherm adsorption. The results of experimental and theoretical studies have shown that the inhibition effect of TEO is better than ITT for X65 in 0.5 M H2SO4.

    更新日期:2018-12-06
  • Environmentally benign conversion of waste polyethylene terephthalate to fluorescent carbon dots for “on-off-on” sensing of ferric and pyrophosphate ions
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-04
    Yaoping Hu, Zhijin Gao, Jie Yang, Hui Chen, Lei Han

    The increasing production of waste polyethylene terephthalate (PET) is a growing problem worldwide. Environmentally benign conversion of waste PET to valuable materials remains a substantial challenge. In this paper, we developed a green route to reuse waste PET for low-cost synthesis of fluorescent carbon dots (CDs) via air oxidation followed by hydrothermal treatment in aqueous H2O2 solution. No expensive, corrosive, or toxic reagents, or severe conditions were required in the synthetic process. The resultant CDs possessed abundant oxygenous groups and unique photoluminescence (PL) properties, which showed a highly selective and sensitive detection of ferric ion (Fe3+) through a PL quenching effect (on-off). The fluorescence of CDs quenched by Fe3+ could be restored specifically with pyrophosphate anion (PPi), rendering the CDs/Fe3+ sensor promising for PPi detection (off-on). The linear ranges for Fe3+ and PPi detections were 0.5–400 and 2–600 μM, and the limit of detections (LODs) were 0.21 and 0.86 μM, respectively. The sensing system applied for Fe3+ and PPi assays in real water samples and human urine achieved good results. After detailed investigations, a possible electron transfer process was proposed for explaining the “on-off-on” sensing mechanism.

    更新日期:2018-12-05
  • Superior activity of Pd nanoparticles confined in carbon nanotubes for hydrogen production from formic acid decomposition at ambient temperature
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-04
    Tian-Yi Ding, Zhi-Gang Zhao, Mao-Fei Ran, Yao-Yue Yang

    Designing highly efficient and low-cost catalysts is essential toward realizing the practical application of hydrogen generation by formic acid decomposition (FAD) under ambient conditions. Herein, we report the synthesis of a hybrid material of Pd nanoparticles encapsulated within carbon nanotubes (CNTs) (Pd-CNTs-in). Transmission electron microscopy images show that most Pd nanoparticles (mean diameter 4.2 ± 0.8 nm) are located inside the nanotubes. Temperature-programmed reduction studies of H2 reveal that the average reduction temperature of the Pd(II) species adsorbed on the interior wall of the CNTs is 12 °C lower than those adsorbed on the outer walls of the CNT. Moreover, the as-prepared Pd-CNTs-in catalysts show extremely high FAD activity and durability at ambient temperature. The turn over frequency (TOF) value is as high as 1135 h-1 for the initial 10 min and does not decay significantly during the consecutive 3-time recycling studies. X-Ray photoelectron spectroscopy (XPS), surface-enhanced infrared spectroscopy (SEIRAS), and gas chromatography (GC) studies indicate that CNT confinement induced electronic structure modulation of Pd could be the major reason for the enhancement of FAD catalysis on the Pd-CNTs-in surface. This work could provide promising strategies for the fabrication of cost-effective and high-active Pd-based catalysts for formic acid dehydrogenation.

    更新日期:2018-12-05
  • Nanoparticle–nanobubble interactions: charge inversion and re-entrant condensation of amidine latex nanoparticles driven by bulk nanobubbles
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-05
    Minmin Zhang, James R.T. Seddon, Serge G. Lemay

    Hypothesis The stability of colloidal suspensions can be influenced by supersaturation of the supporting electrolyte with gas. It has been proposed that this effect can be attributed to the formation of nanobubbles on the surface of the colloidal particles, in turn influencing DLVO forces. While previous interpretations have focused primarily on van der Waals interactions, probing positively charged particles can provide complementary insight into electrostatic interactions. Experiments High-power water electrolysis creates an aqueous solution supersaturated with oxygen and hydrogen. We study the ability of this solution to influence the electrophoretic properties of positive nanoparticles as a function of the particle–gas ratio. Both the ζ -potential and the effective hydrodynamic diameter of the resulting nanoentities were studied using dynamic light scattering for a range of nanoparticle sizes. Findings Gas-saturated solution interacts strongly with positive nanoparticles by decreasing and ultimately reversing the sign of their ζ -potential, which we attribute to the nucleation of negatively charged bubbles at the solid-liquid interface. This leads to re-entrant condensation of the particles near their point of zero charge, as directly observed via an increase in hydrodynamic diameter and macroscopic aggregation. These results indicate that modulation of electrostatic interactions can be the dominant mechanism for gas-particle interactions in these systems.

    更新日期:2018-12-05
  • Energy and cost-efficient nano-Ru-based perovskites/RGO composites for application in high performance supercapacitors
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-05
    Ahmed Galal, Hagar K. Hassan, Nada F. Atta, Timo Jacob

    Nano-Ru-based perovskites RGO are prepared simultaneously in presence of various A-metal salts (A= Sr, Ba or Ca salts) using two different methods for reaction initiation. No further calcination step is needed for the formation of well-defined perovskite structure. Graphene oxide (GO) is used as a fuel to prepare various Ru-based perovskites for the first time. The resulted low-Ru content nanocomposites are used as supercapacitor electrodes in a neutral electrolyte (1.0 M NaNO3). The results show that the specific capacitance of the resulted nanocomposites strongly depends on the method of their preparation as well as the type of A-site of the nanocomposites. Ru-based perovskites RGO nanocomposites that are prepared by combustion method show higher specific capacitance than those prepared by microwave irradiation. The maximum specific capacitance of Sr-, Ba- and Ca-RG-C composites at scan rate 2 mV.s-1 are 564 (598 mF.cm-2), 460 (487 mF.cm-2) and 316 (336 mF.cm-2) F.g -1, respectively. This value is higher than our previous work using a physical mixture between the individually prepared RGO and SrRuO3. Lowest values for specific capacitance are obtained when using CaRuO3/RGO prepared using microwave-assisted method (Ca-RG-M). The resulted A-RG-nanocomposites show very high cycling stability and good specific capacitance compared to other Ru-based structures previously reported in the literature. A correlation is defined between the structure and specific capacitance of the nanocomposites. It is confirmed that the nanocomposite size, morphology and distribution over the RGO matrix influence the supercapacitor characteristics.

    更新日期:2018-12-05
  • Conformational and solution dynamics of hemoglobin (Hb) in presence of a cleavable gemini surfactant: Insights from spectroscopy, atomic force microscopy, molecular docking and density functional theory
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-03
    Imtiyaz Ahmad Bhat, Bibhisan Roy, Partha Hazra, Kabir-ud-Din

    Herein, we have explored the conformational alterations of hemoglobin (Hb) in presence of a cleavable gemini surfactant (C16-C4O2-C16). The concerned surfactant was found to induce significant structural perturbations in Hb. UV-vis spectroscopy, steady-state/time-resolved fluorescence, and other utilized techniques have authenticated the complexation of Hb with the gemini surfactant. CD has demonstrated the alterations in secondary structural elements (α-helicity, β-sheet, β-turn, and random coil) of Hb upon C16-C4O2-C16 addition. Atomic force microscopy (AFM) has revealed the existence of a unique star-shaped gemini surfactant microstructures aligned to Hb in a necklace pattern. The 1H-NMR peak broadening and lower delta values hints at the binding of the concerned gemini surfactant to Hb. Molecular docking and DFT calculations have further substantiated the Hb-gemini complex formation and the involvement of electrostatic/hydrophobic forces therein. In future, these results might pave-the-way to construct self-assembled, sustainable, and green surfactant-protein mixtures for their end-use in industrial, engineering, biomedical, drug delivery, gene transfection, and other relevant excipient formulations.

    更新日期:2018-12-04
  • Enhanced efficiency and stability of perovskite solar cells using polymer-coated bilayer ZnO nanocrystals as the multifunctional electron‐transporting layer
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-03
    Khalid Mahmood, Arshi Khalid, Muhammad Shahzad Zafar, Faisal Rehman, Madsar Hameed, Muhammad Taqi Mehran

    A novel polymer-coated ZnO based bilayer electron transporting material is investigated for highly efficiecy perovskite solar cells. The bilayer ETM consisting of an upper-layer of ZnO nanosheets and a lower-layer of ZnO nanoparticles demonstrates the averaged power conversion efficiency of 13.11% and a maximum power conversion efficiency of 15.13%, compared to single-layers of nanosheets (power conversion efficiency =11.73%) and nanoparticles (power conversion efficiency =11.08%) films. A conformal coating of a polymer such as polyethylenimine on the surface of bilayered film leading to a significant boost in power conversion efficiency upto 16.39%, thanks to the reduced work fucntion, rapid electron transport and better perovskite infiltration into the bilayer electron transporting material.

    更新日期:2018-12-04
  • Insight into photocatalytic activity, universality and mechanism of copper/chlorine surface dual-doped graphitic carbon nitride for degrading various organic pollutants in water
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-03
    Chunmei Li, Siyu Yu, Xiaoxu Zhang, Yun Wang, Chunbo Liu, Gang Chen, Hongjun Dong

    It is still a challenging work to realize the universality of photocatalytic materials for unselective removing various organic pollutants in water. Here a surface dual-doped Cu/Cl-g-C3N4 photocatalyst is firstly prepared, which exhibits much more superior photocatalytic performance for degrading multifarious persistent organic pollutants including tetracycline hydrochloride (TC-HCl), o-chlorophenol, bisphenol A and 2-mercaptobenzothiazole in water than pure g-C3N4. The high-efficiency and unselective photocatalytic degradation performance derives from the surface dual-doped effect of Cu/Cl elements on g-C3N4, which results in the extended visible light harvest range, elevated CB potential and improved the separation efficiency of charge carriers. The intermediate products, degradation pathway, degree of mineralization and reaction mechanism of representative TC-HCl pollutant over the surface dual-doped Cu/Cl-g-C3N4 photocatalyst are revealed in depth. This work makes an important development for treating the persistent organic pollutants in the water environments by exploiting new, low-cost and high-efficiency photocatalytic materials.

    更新日期:2018-12-04
  • Effects of oxidation on the physicochemical properties of polyunsaturated lipid membranes
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-03
    Elisa Parra-Ortiz, Kathryn L. Browning, Liv S. E. Damgaard, Randi Nordström, Samantha Micciulla, Saskia Bucciarelli, Martin Malmsten

    The exposure of biological membranes to reactive oxygen species (ROS) plays an important role in many pathological conditions such as inflammation, infection, or sepsis. ROS also modulate signalling processes and produce markers for damaged tissue. Lipid peroxidation, mainly affecting polyunsaturated phospholipids, results in a complex mixture of oxidized products, which may dramatically alter membrane properties. Here, we have employed a set of biophysical and surface-chemical techniques, including neutron and X-ray scattering, to study the structural, compositional, and stability changes due to oxidative stress on phospholipid bilayers composed of lipids with different degrees of polyunsaturation. In doing so, we obtained real-time information about bilayer degradation under in situ UV exposure using neutron reflectometry. We present a set of interrelated physicochemical effects, including gradual increases in area per molecule, head group and acyl chain hydration, as well as bilayer thinning, lateral phase separation, and defect formation leading to content loss upon membrane oxidation. Such effects were observed to depend on the presence of polyunsaturated phospholipids in the lipid membrane, suggesting that these may also play a role in the complex oxidation processes occurring in cells.

    更新日期:2018-12-04
  • Microfluidics-based self-assembly of peptide-loaded microgels: Effect of three dimensional (3D) printed micromixer design
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-04
    Bruno C. Borro, Adam Bohr, Saskia Bucciarelli, Johan P. Boetker, Camilla Foged, Jukka Rantanen, Martin Malmsten

    In an effort to contribute to research in scalable production systems for polymeric delivery systems loaded with antimicrobial peptides (AMPs), we here investigate effects of hydrodynamic flow conditions on microfluidic particle generation. For this purpose, rapid prototyping using 3D printing was applied to prepare micromixers with three different geometric designs, which were used to prepare Ca2+-cross-linked alginate microgels loaded with the AMP polymyxin B in a continuous process. Based on fluid dynamic simulations, the hydrodynamic flow patterns in the micromixers were designed to be either (i) turbulent with chaotic disruption, (ii) laminar with convective mixing, or (iii) convective with microvortex formation. The physicochemical properties of the microgels prepared with these micromixers were characterized by photon correlation spectroscopy, laser-Doppler micro-electrophoresis, small-angle x-ray scattering, and ellipsometry. The particle size and compactness were found to depend on the micromixer geometry: From such studies, particle size and compactness were found to depend on micromixer geometry, the smallest and most compact particles were obtained by preparation involving microvortex flows, while larger and more diffuse microgels were formed upon laminar mixing. Polymyxin B was found to be localized in the particle interior and to cause particle growth with increasing peptide loading. Ca2+-induced cross-linking of alginate, in turn, results in particle contraction. The peptide encapsulation efficiency was found to be higher than 80% for all investigated micromixer designs; the highest encapsulation efficiency observed for the smallest particles generated by microvortex-mediated self-assembly. Ellipsometry results for surface-immobilized microgels, as well as results on peptide encapsulation, demonstrated electrolyte-induced peptide release. Taken together, these findings demonstrate that rapid prototyping of microfluidics using 3D-printed micromixers offers promises for continuous manufacturing of AMP-loaded microgels. Although the micromixer combining turbulent flow and microvortexes was demonstrated to be the most efficient, all three micromixer designs were found to mediate self-assembly of small microgels displaying efficient peptide encapsulation. This demonstrates the robustness of employing 3D-printed micromixers for microfluidic assembly of AMP-loaded microgels during continuous production.

    更新日期:2018-12-04
  • Piezoelectric Barium Titanate Nanostimulators for the Treatment of Glioblastoma Multiforme
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-04
    Attilio Marino, Enrico Almici, Simone Migliorin, Christos Tapeinos, Matteo Battaglini, Valentina Cappello, Marco Marchetti, Giuseppe de Vito, Riccardo Cicchi, Francesco Saverio Pavone, Gianni Ciofani

    Major obstacles to the successful treatment of gliolastoma multiforme are mostly related to the acquired resistance to chemotherapy drugs and, after surgery, to the cancer recurrence in correspondence of residual microscopic foci. As innovative anticancer approach, low-intensity electric stimulation represents a physical treatment able to reduce multidrug resistance of cancer and to induce remarkable anti-proliferative effects by interfering with Ca2+ and K+ homeostasis and by affecting the organization of the mitotic spindles. However, to preserve the proliferation and behavior of healthy cells, it is utterly important to direct the electric stimuli only to malignant cells. In this work, we propose a nanotechnological approach based on ultrasound-sensitive piezoelectric nanoparticles to remotely deliver electric stimulations to glioblastoma cells. Barium titanate nanoparticles (BTNPs) have been functionalized with an antibody against the transferrin receptor (TfR) in order to obtain the dual targeting of blood-brain barrier and of glioblastoma cells. The remote ultrasound-mediated piezo-stimulation allowed to significantly reduce in vitro the proliferation of glioblastoma cells and, when combined with a sub-toxic concentration of temozolomide, induced an increased sensitivity to the chemotherapy treatment and remarkable anti-proliferative and pro-apoptotic effects.

    更新日期:2018-12-04
  • Ultra-low Loading of Pd5 Nanoclusters on Carbon Nanotubes as Bifunctional Electrocatalysts for the Oxygen Reduction Reaction and the Ethanol Oxidation Reaction
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-04
    Zhihua Zhuang, Wei Chen

    How to reduce the usage of precious metals in electrocatalysts is a big challenge for the development of fuel cells. Metal nanoclusters (NCs) are highly desirable as active catalysts, but palladium nanoclusters (Pd NCs) have been less well developed than other metal clusters, such as gold, silver and copper, owing partly to the difficulties in size-controlled synthesis. Here, based on N, N-dimethylformamide (DMF)-mediation and ligand-exchange reaction, atomically precise Pd5(C12H25S)13 nanoclusters are successfully synthesized. By loading the as-prepared Pd5 nanoclusters on multiwalled carbon nanotubes (MWCNTs) and the following pyrolysis to remove the thiolate ligands, the surface-cleaned Pd5 clusters (Pd5 NCs/MWCNTs) can serve as efficient electrocatalysts for the oxygen reduction reaction (ORR) and the ethanol oxidation reaction (EOR). With ultra-low mass loading of Pd (2%), the Pd5 NCs showed higher mass and specific activities and better durability than the commercial Pd/C catalyst (5wt. %) for the ORR. At 0.8 V, the mass and specific activities of Pd5 NCs/MWCNTs are 5.70 and 4.53 times higher than the commercial Pd/C catalyst, respectively. As for the EOR, the Pd5 NCs/MWCNTs exhibited lower onset potential (0.39 V) and peak potential (0.81 V) than the commercial Pd/C catalyst (0.44 and 0.89 V). Electrochemical impedance spectroscopy (EIS) measurements indicated that for the EOR, the Pd5 nanoclusters have a much smaller charge transfer resistance (Rct) than the commercial Pd/C. The high-performance electrocatalytic properties of Pd5 NCs for the ORR and EOR could be ascribed to the relatively high surface area-to-volume ratio and high density of exposed surface atoms of the Pd5 nanoclusters.

    更新日期:2018-12-04
  • Binding of norharmane with RNA reveals two thermodynamically different binding modes with opposing heat capacity changes
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-04
    Bijan K. Paul, Narayani Ghosh, Saptarshi Mukherjee

    The binding interaction of a prospective anti-cancer photosensitizer, norharmane (NHM, 9H-pyrido[3,4-b]indole) with double stranded RNA reveals a primarily intercalative mode of binding. Steady-state and time-resolved fluorescence spectroscopic results demonstrate the occurrence of drug-RNA binding interaction as manifested through environment-sensitive prototropic equilibrium of NHM. However, the key finding of the present study lies in unraveling the complexities in the NHM-RNA binding thermodynamics. Isothermal Titration Calorimetry (ITC) results reveal the presence of two thermodynamically different binding modes for NHM. An extensive temperature-dependence investigation shows that the formation of Complex I is enthalpically (ΔHI < 0) as well as entropically (TΔSI > 0) favored with the enthalpic (entropic) contribution being increasingly predominant in the higher (lower) temperature regime. On the contrary, the formation of Complex II reveals a predominantly enthalpy-driven signature (ΔHI < 0) along with unfavorable entropy change (TΔSI < 0) with gradually decreasing enthalpic contribution with temperature. Such differential dependences of ΔHI and ΔHII on temperature subsequently lead to opposing heat capacity changes underlying the formation of Complex I and II (ΔCpI<0andΔCpII>0). A negative ΔCp underpins the pivotal role of ‘hydrophobic effect’ (release of ordered water molecules) for the formation of Complex I, while a positive ΔCp marks the thermodynamic hallmark for ‘hydrophobic hydration’ (solvation of hydrophobic (or nonpolar) molecular surfaces in aqueous medium) for formation of Complex II. A detailed investigation of the effect of ionic strength enables a component analysis of the total free energy change (ΔG).

    更新日期:2018-12-04
  • A remarkable thermosensitive hydrogel cross-linked by two inorganic nanoparticles with opposite charges
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-04
    Shuo Wang, Zhaofu Zhang, Linfeng Dong, Geoffrey I.N. Waterhouse, Qihai Zhang, Lifang Li

    Herein, we report the successful synthesis of a series of poly (N-isopropylacrylamide) (PNIPA)/layered double hydroxides (LDHs)/nano-hydroxyapatite (nano-HA) hydrogels via in-situ radical polymerization. The internal morphology, thermo sensitivity, rheological properties, swelling behavior and hemocompatibility of the PNIPA/LDHs/HA composite hydrogels were systematically investigated. Results show that the hydrogels had a reversible sol-gel transformation around 33 oC. Interactions between the positively charged LDHs and negatively charged nano-HA particles created a highly porous hydrogel network. The composite hydrogels exhibited excellent hemocompatibility, incredible mechanical toughness and reversible swelling /deswelling behavior. To our knowledge, this is the first reported study to use two types of inorganic nanoparticle with opposing charges as hydrogel crosslinking agents. Based on its properties, we expect this hydrogel has broad applications potential in tissue engineering, drug delivery and biosensor development.

    更新日期:2018-12-04
  • Interfacial uploading of luminescent hexamolybdenum cluster units onto amino-decorated silica nanoparticles as new design of nanomaterial for cellular imaging and photodynamic therapy
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-04
    Julia Elistratova, Alsu Mukhametshina, Kirill Kholin, Irek Nizameev, Maksim Mikhailov, Maxim Sokolov, Rafil Khairullin, Regina Miftakhova, Ghazal Shammas, Marsil Kadirov, Konstantin Petrov, Albert Rizvanov, Asiya Mustafina

    The present work introduces a facile synthetic route to embed phosphorescent K2[{Mo6I8}I6] and (nBu4N)2[{Mo6I8}(CH3COO)6] clusters (C) onto silica-water interface of amino-decorated silica nanoparticles (SNs, 60±6 nm). The assembled C-SNs gain in the luminescence intensity, which remains stable within three months after their assembly. High uptake capacity of the clusters (8700 of K2[{Mo6I8}I6] and 6500 of (nBu4N)2[{Mo6I8}(CH3COO)6] per the each nanoparticle) derives from ionic self-assembly and coordination bonds between the cluster complexes and ionic (amino- and siloxy-) groups at the silica surface. The coordination via amino- or siloxy-groups restricts aquation and hydrolysis of the embedded clusters, in comparison with the parent K2[{Mo6I8}I6] and (nBu4N)2[{Mo6I8}(CH3COO)6. High potential of the assembled nanoparticles in the ROS generation was revealed by EPR measurements facilitated by spin trapping. The high positive charge and convenient colloid stability of the assembled C-SNs hybrids are the prerequisite for their efficient cellular uptake, which is exemplified in the work by MCF-7 cell line. The measured dark and photoinduced cytotoxicity of the C-SNs hybrids reveals significant photodynamic therapy effect on the MCF-7 cancer cell line versus the normal cells. This effect is entirely due to the embedded clusters and is dependent on the chemical composition of the cluster.

    更新日期:2018-12-04
  • Penetration dynamics through nanometer-scale hydrophilic capillaries: beyond Washburn’s equation and extended menisci
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-03
    Kang-Ching Chu, Heng-Kwong Tsao, Yu-Jane Sheng

    Hypothesis Recently, the naoncapillary devices with the channel width about 2-3 water molecules have been fabricated. Water transport through these nanoslits showed unexpectedly fast flow, revealing the failure of Washburn’s equation. Experiments Liquid penetration into a nanocapillary made of two parallel walls is explored by many-body dissipative particle dynamics. Both partial wetting and total wetting walls are considered and the no-slip boundary condition is satisfied. Findings The wicking velocity generally obeys Washburn’s equation, but the dynamic contact angle (CA) has to be employed. The dynamic CA (θD) relies on the penetration rate and is always larger than the equilibrium CA. The breakdown of Washburn’s equation occurs under two conditions, (i) the channel width close to molecular size and (ii) the positive spreading coefficient is large enough. Both cases come about when the wicking velocity in a nanoslit exceeds the maximum value corresponding to cos(θD) = 1. The failure of Washburn’s equation is attributed to the invalidity of Young-Laplace equation associated with undefined meniscus. The extended meniscus will be developed as a wall of the nanoslit continues to extend outside the exit mouth. The shapes of extended menisci are discussed for both partial wetting and total wetting surfaces.

    更新日期:2018-12-03
  • Unraveling the Intrinsic Enhancement of Fluorine Doping in the Dual-doped Magnetic Carbon Adsorbent for the Environmental Remediation
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-03
    Jiangnan Huang, Yonghai Cao, Hejie Wen, Ju Zhang, Hongjuan Wang, Hao Yu, Feng Peng

    Heteroatom doping endows magnetic carbons with unique electronic features and rich surface chemistry, significantly enhancing their adsorption performances for the environmental remediation. In this work, fluorine and nitrogen co-doped magnetic nanocarbon fibers (FN-MCFs) were prepared via a facile carbonization method combined with electrospinning procedure. FN-MCFs were used as adsorbents for Cr(VI) removal, displaying a remarkable activity with as high as 153.61 mg/g and 0.58 mg/m2 of the Cr(VI) removal ability. F and N co-doping in magnetic nanocarbon fibers offered a higher specific surface area and disorder degree in graphite layer, therefore providing more active sites on the adsorbents surface. The electrostatic adsorption and reduction reaction between the Fe0, Fe2+ nanoparticles or edge carbons and Cr(VI) ions played significant roles in the adsorption process, which was believed to be facilitated by F and N co-doping. It was found that chemical adsorption was the main process in this work. Moreover, the adsorption capacity of FN-MCFs was majorly influenced by the doping level or doping type. F doping was found to be more important than N doping for the Cr(VI) removal in the dual-doping system. In addition, the excellent reusability of the FN-MCFs was observed.

    更新日期:2018-12-03
  • Co-Al nanosheets derived from LDHs and their catalytic performance for syngas conversion
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-03
    Mingsheng Luo, Shun Xu, Qingyang Gu, Zuoxing Di, Qinglong Liu, Zhijun Zhao

    Layered double hydroxides (LDHs) were innovatively employed in this study as catalyst for synthesis gas conversion to chemicals, such as oxygenates. Cobalt-aluminium layered double hydroxides (LDHs) was first prepared at different temperatures. Lactate was then successfully intercalated into the LDH by ion-exchange method before the material was further delaminated in the water at ambient temperature. The above sample was characterized with SEM, TEM and AFM, and separately dispersed nanosheets can be clearly observed. These prepared lamellas were then applied in aqueous-phase synthesis gas conversion reaction. These catalysts generated a superior activity of 0.055-0.675 mo l CO · m o l Co - 1 · h - 1 and greater oxygenated product (acetaldehyde) selectivity (SOxy = 75-88%) than conventional cobalt Fisher-Tropsch (FT) synthesis catalysts. Ammonium ion showed some effect of the selectivity of the acetaldehyde. This original research result suggests a promising application of the mono-dispersed ultrathin cobalt-bearing nanosheets (LDHs) in the aqueous phase syngas conversion to valuable oxygenate products.

    更新日期:2018-12-03
  • Construction of core-shell mesoporous carbon nanofiber@nickel cobaltite nanostructures as highly efficient catalysts towards 4-nitrophenol reduction
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-03
    Ying Yang, Dehong Zeng, Shuai Shao, Shijie Hao, Gangli Zhu, Baijun Liu

    We herein report small sized nickel cobaltite (NiCo2O4) nanosheets (103∼144 nm × 71∼97 nm) firmly coated on mesoporous carbon nanofibers (MCNFs), as active and stable catalysts for degradation of 4-nitrophenol in sewage with NaBH4 as the reductant. MCNFs with surface O-functionalities were first constructed by morphology-conserved transformation of zinc-trimesic acid fibers, which provide scaffolds to anchor trisodium citrate-induced Ni-Co hydroxide nanosheets. Upon calcination, the resultant core-shell MCNF@NiCo2O4 nanostructures were fabricated and characterized by SEM, TEM, X-ray diffraction, Raman spectroscopy, thermogravimetric analysis (TGA), X-ray photoelectron spectroscopy (XPS) and N2 adsorption/desorption techniques. The anchored NiCo2O4 nanosheets were dense (75 wt%) but well-dispersed on the surface of MCNF (pore size 4.0 nm), and proved to be highly active and stable towards the reduction of 4-nitrophenol to 4-aminophenol. It showed a large activity factor of 2.53 s–1 g–1, exceeding most transition metal oxide catalysts, and MCNF@NiCo2O4 could be cycled at least 20 times without obvious loss of activity. Temperature-programmed desorption and reduction by hydrogen (H2-TPD and H2-TPR) studies showed that, the metal oxide dispersion and thereby the amount of H2 adsorbed were enhanced, and the interfacial interaction was also strengthened. These should be responsible for the excellent activity and stability of MCNF@NiCo2O4 towards 4-nitrophenol reduction.

    更新日期:2018-12-03
  • Development of Ca2+-based, ion-responsive superabsorbent hydrogel for cement applications: self-healing and compressive strength
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-03
    Miaomiao Hu, Jintang Guo, Jiangbo Du, Zhenxing Liu, Pengpeng Li, Xiangkui Ren, Yakai Feng

    Superabsorbent polymers (SAPs) are broadly applied in cement and concrete. However, the increased macrovoids resulting from the absorption/desorption of SAPs, remarkably reduced the resulting mechanical properties. In this study, we prepared superabsorbent CaAlg hydrogels by crosslinking Ca2+ and sodium alginate (NaAlg). The ion-responsive behavior of CaAlg was measured, and results showed at lower the Ca2+ concentrations, higher swelling potentials were observed, which was consistent with what was expected with the formation of a less dense network. This interesting dependence on Ca2+ concentration likely avoids the formation of large macro-pores during the mixing process of cement and results in increased swelling when cracks occur and water enters the crevices. The results of compressive strength measurements demonstrated that the addition of 0.5 wt% CaAlg resulted in a negligible reduction (0.014%) in compressive strength due to the limited swelling capacity in pore solution. Interestingly, in the sodium silicate self-healing system, in addition to the widely reported self-sealing effects upon adsorption of additional water, CaAlg also accelerates the precipitation of calcium silicate hydrates (C-S-H) by providing Ca2+, which makes the healing process more efficient.

    更新日期:2018-12-03
  • Emulsion droplets’ self-faceting route to solid icosahedra and other polyhedra
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-02
    Orlando Marin, Maria Alesker, Shani Guttman, Gregory Gershinsky, Eitan Edri, Hagay Shpaisman, Rodrigo E. Guerra, David Zitoun, Moshe Deutsch, Eli Sloutskin

    Hypothesis Temperature-controlled self-faceting of liquid droplets has been recently discovered in surfactant-stabilized alkane-in-water emulsions. We hypothesize that similar self-faceting may occur in emulsion droplets of UV-polymerizable linear hydrocarbons. We further hypothesize that the faceted droplet shapes can be fixed by UV-initiated polymerization, thus providing a new route towards the production of solid polyhedra. Experiments Temperature-induced shape variations were studied by optical microscopy in micron-size emulsion droplets of UV-polymerizable alkyl acrylate. When polymerized, the resultant solid particles’ 3D shape and internal structure were determined by combined scanning electron microscopy (SEM) and focused ion beam (FIB) slicing. The SEM and FIB nanoscale resolution provided a far greater detail imaging than that achievable for the liquid droplets, which could only be studied by optical microscopy, severely limiting their 3D shape determination. Findings We demonstrate the formation of solid icosahedra, polyhedral platelets, and rods of hitherto-unreported sizes, well below the 3D-printing resolution ( m). The presence of icosahedral shapes and the absence of any resolvable internal structure at sub- m length scales, are in line with the surface-freezing-driven mechanism proposed for the faceting phenomenon. Further development of the method presented here may allow large-quantity production of shaped micron- to nano- sized colloidal building blocks for 3D metamaterials and other applications.

    更新日期:2018-12-02
  • Carboxylated Nanocellulose Foams as Superabsorbents
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-01
    Llyza Mendoza, Laila Hossain, Emma Downey, Camilla Scales, Warren Batchelor, Gil Garnier

    Hypothesis: Carboxylated nanocellulose fibres formed into foam structures can demonstrate superabsorption capacity. Their performance can be engineered by changing process variables. Experiments: TEMPO-oxidised cellulose nanofibres of varying concentration and surface charge are produced from hardwood kraft pulp. Foams were prepared through a 2-step freezing and lyophilisation process. The absorption capacity of water and saline solution (0.9wt.%) were measured as a function of time and related to the foam structure. Findings: The absorption capacity of nanocellulose foams can be manipulated from initial gel properties and processing conditions. Pore structure and distribution of nanocellulose foams are dictated by fibre content and charge density and freezing rate. The best performing foams are at 0.3-0.5 wt.%, with a carboxylate concentration of 1.2 mmol/g and frozen at -86°C before freeze-drying, which can absorb 120 g H2O/ g fibre. Fibre surface charge influences the absorption capacity of the foams by dictating the amount of participating carboxylate groups. Absorption capacity in saline (60 g/g) is lower than in deionised water (120 g/g); but is only slightly lower than that of a commercial polyacrylic acid (PAA) SAPs (80g/g). Nanocellulose foams are attractive renewable alternatives for superabsorbent applications, contributing to a reduction of plastic microspheres.

    更新日期:2018-12-01
  • One-pot synthesis of highly branched Pt@Ag core-shell nanoparticles as a recyclable catalyst with dramatically boosting the catalytic performance for 4-nitrophenol reduction
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-12-01
    Zhi-Suo Lv, Xiao-Yan Zhu, Han-Bin Meng, Jiu-Ju Feng, Ai-Jun Wang

    Herein, highly branched Pt@Ag core-shell nanoparticles (Pt@Ag NPs) were fabricated by a facile one-pot wet-chemical approach, where poly(ethyleneimine) (PEI) served as structure-directing and capping agents. Their structure, morphology and composition were mainly characterized by a set of techniques. And their growth mechanism was discussed in some detail. The prepared catalyst exhibited remarkable enhancement in catalytic activity of 4-nitrophenol (4-NP) reduction as a proof-of-concept application, surpassing commercial Pt black and home-made Ag NPs catalysts. Also, the as-obtained catalyst showed superior stability without sacrificing the catalytic activity. These observations endow the catalyst possibility for practical applications in nitrophenols environmental remediation.

    更新日期:2018-12-01
  • Synthesizing Nickel-Based Transition Bimetallic Oxide via Nickel Precursor-Free Hydrothermal Reaction for Battery Supercapacitor Hybrid Devices
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-30
    Pin-Yan Lee, Lu-Yin Lin

    The Ni foam can act as the nickel ion source and the current collector for synthesizing Ni-based compounds using the hydrothermal synthesis especially in the acid condition. Using Ni foam as the Ni2+ source can grow materials on the substrate directly and uniformly since nickel ions are released from substrate thoroughly. Nickel-based bimetallic oxides are intensively investigated as battery-type materials for battery supercapacitor hybrid devices (BSHD) because of high electrical conductivities and abundant transition states for inducing multiple redox reactions. In this study, Mo, Mn, Al, and W precursors are simply added in Ni precursor-free acid solution for hydrothermal synthesis using Ni foam as the nickel ion source and the current collector to synthesize Ni-based bimetallic oxide electrodes for BSHD. The morphology of nickel-based bimetallic oxide prepared with and without incorporating the structure-directing agent is also carefully discussed. The highest specific capacitance (CF) of 1.80 F/cm2 corresponding to the capacity of 4.54 mAh/cm2 at 5 mA/cm2 is attained for the nickel molybdenum oxide (Ni-Mo oxide) electrode. The Ni-Mo oxide-based BSHD shows a potential window of 1.8 V, a CF value of 223.53 mF/cm2 corresponding to the capacity of 1.45 mAh/cm2 at 5 mA/cm2, the maximum energy density of 4.60 Wh/kg at the power density of 0.21 kW/kg, and the CF retention of 90% after 6000 times charging/discharging process.

    更新日期:2018-11-30
  • Preparation of mesoporous magnetic Fe3O4/C nanomaterial and its excellent adsorption properties
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-07-20
    Junhong Wang, Qiang Zhang, Junhai Liu, Xiaohui Ji, Jianqi Ma, Guanghui Tian

    Mesoporous magnetic Fe3O4/C nanomaterials were synthesized through hydrothermal method, SBA-15 prepared by the improved method as hard template, glucose as carbon source and ferric chloride hexahydrate as iron source. As-prepared magnetic nanomaterials were characterized by means of X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), N2 adsorption- desorption isothermals, vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscope (FTIR) and Raman spectrum. And that the adsorption properties for organic dyes in water of as-synthesized magnetic materials were further studied. Results indicate that prepared magnetic carbon nanomaterials show hollow spherical structure similar to a bunch of grapes, and that magnetite Fe3O4 particles are embedded in the matrix of carbon nanoscale. The sample has larger specific surface up to 522.7 m2/g, pore volume of 0.4454 cm3/g, pore diameter of 3.5 nm and saturation magnetization of 31.9 emu/g. At the same time, as-synthesized materials exhibit excellent adsorption properties and reutilization, so that the total adsorption capacity is up to 400 mg/g to methyl orange, 600 mg/g to methylene blue and 150 mg/g to rhodamine B under the natural pH of solution. Therefore, as-prepared magnetic carbon nanomaterials will have potential industrial application prospects in environment water purification.

    更新日期:2018-11-29
  • First-principles modeling of water permeation through periodically porous graphene derivatives
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-29
    Jin Soo Lim, Gunn Kim

    Polyphenylene superhoneycomb network (PSN) and covalent triazine framework (CTF) are experimentally realized periodically porous graphene derivatives. Such ultrathin layers with homogeneously distributed pores of controllable sizes are highly desirable for applications in molecular separations such as water purification. The permeation energy barrier is expected to be a function of not only the pore size, but also the specific permeation trajectory as determined by hydrogen bonding interactions at the water-pore interface.Here, we report a detailed first-principles study of permeation of a single H2O molecule through a monolayer PSN and CTF-0, as well as its diffusion behavior inside a bilayer PSN. The calculated energy barrier of 1.44 eV indicates the infeasibility of using PSN as a water permeation membrane. However, the barrier decreases considerably to 0.94 eV when three C-H pairs at the pore are replaced with N atoms into CTF-0. Inside a bilayer PSN, we find facile interlayer sliding as well as interlayer expansion owing to out-of-plane reorientation of the H2O molecule. In all cases, the functional groups at the pore significantly alter the orientation of the H2O molecule and the corresponding barriers. Such atomistic insights at the porous interface would provide a valuable guidance in advancing rational pore design principles.

    更新日期:2018-11-29
  • Facile Synthesis of Nitrogen-Enriched Nanoporous Carbon Materials for High Performance Supercapacitors
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-29
    Dandan Guo, Jin Qian, Ranran Xin, Zhen Zhang, Wei Jiang, Gengshen Hu, Maohong Fan

    Mesoporous carbons with ultrahigh nitrogen content were prepared for supercapacitors through the hard template method. Silica nanoparticles were used as the hard template, and ethylenediamine and CCl4 served as precursor. Large amount of mesopores were generated through removing the silica nanoparticles with HF. The effect of carbonization temperature on the pore structure and nitrogen content and thus on the capacitive performance of supercapacitors were investigated. It was found that the higher carbonization temperature leads to an initial increase and then decrease of specific surface area and a continuous decrease in N content. The sample carbonized at 700 oC (NC700) shows the highest capacitance (306 F g-1) due to the higher surface area (533 m2g-1) and ultrahigh N content (18.06%). The increase in specific surface area results in improvement of double-layer capacitance, while the N element increases the pseudocapacitance and the wettability of the carbons. In addition, NC700 shows excellent stability with 96.6% capacitance retention even after 10000 cycles at a current density of 3 A g-1.

    更新日期:2018-11-29
  • 3D Channel-Structured Graphene as Efficient Electrodes for Capacitive Deionization
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-28
    Liang Chang, Yun Hang Hu

    Capacitive deionization (CDI), which is one of up-and-coming water treatment technologies, is based on ion electrostatic adsorption on electrode surface. Herein, three-dimensional channel-structured graphene (CSG), which was synthesized via exothermic reaction between liquid potassium and carbon monoxide gas, was demonstrated as an efficient electrode material for CDI. Namely, the CSG electrode exhibited a specific capacity of 207.4 F/g at 0.2 A/g in 1M NaCl aqueous solution. In a batch-mode recycling system, the electrosorption capacity of CSG can achieve 5.70 and 9.60 mg/g at 1.5 V in 50 and 295 mg/l NaCl aqueous solutions, respectively. The excellent electrosorption capacity of CSG, especially under low saline concentration, can be attributed to the synergistic effect of its large surface area (711.9 m2/g), unique channel structure, and oxygen functional groups.

    更新日期:2018-11-28
  • Low-Cost, High-Performance Supercapacitor Based on Activated Carbon Electrode Materials Derived from Baobab Fruit Shells
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-28
    Asim A. Mohammed, Chao Chen, Zhihong Zhu

    Due to an effective synthesis strategy, two kinds of hierarchical porous activated carbons were derived via KOH and H3PO4 activation and carbonization processes from baobab fruit shells (BFSs) used as a green and low-cost biomass precursor. The physicochemical properties and the morphological structure of the baobab fruit shell derived carbons (BFSCs) were systematically studied by scanning electron microscopy (SEM), X-ray diffraction (XRD), Raman spectra, nitrogen adsorption/desorption isotherms and X-ray photoelectron spectroscopy (XPS) techniques. The biomass-derived activated carbons, BFSC1 (using KOH activation), and BFSC2 (using H3PO4 activation), obtained exhibit high specific capacitances of 233.48 F g-1 and 355.8 F g-1 at a current density of 1 A g-1, respectively, due to their different surface structures and high specific surface areas. Furthermore, the as-assembled, flexible all-solid-state supercapacitor devices based on the BFSC electrodes exhibit a high specific capacitance of 58.67 F g-1 at 1 A g-1 and a high energy density of 20.86 Wh kg-1 at a power density of 400 W kg-1. This facile route highlights the exciting possibility of utilizing waste baobab fruit shells to produce low-cost, green and high-performance carbon-based electrode materials for sustainable electrochemical energy storage systems.

    更新日期:2018-11-28
  • Rheo-SANS study on relationship between micellar structures and rheological behavior of cationic gemini surfactants in solution
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-28
    Hiroki Iwase, Risa Kawai, Ken Morishima, Shin-ichi Takata, Tomokazu Yoshimura, Mitsuhiro Shibayama

    HypothesisGemini surfactant 12–2–12 (dimethylene-1,2-bis(dodecyl dimethylammonium bromide)) solutions are known to show shear thickening and thinning under salt-free conditions. Because the rheological behavior of the wormlike micelles formed by 12–2–12 in solution is related to their structure, we expected that changes to the precursor structure would affect their rheological behaviors. It is also important to understand the effect of the introduction of a spacer group in the 12–2–12 molecules on the rheological behavior and structure of the wormlike micelles under shear flow.ExperimentsSimultaneous small-angle neutron scattering and rheological measurements (Rheo-SANS) of the 12–2–12 solutions were performed. We exhaustively studied the structural changes in the wormlike micelles upon increasing shear rate.FindingsWe found that the wormlike micelles were oriented in the direction of the flow due to elongation and that changes to the precursor of the wormlike micelles did not affect the shear thickening. As a precursor structural change of shear thinning, the wormlike micelles elongated while maintaining their orientation. We found that an increase in the molecular curvature of the 12–2–12 due to the introduction of a spacer-group contributed to the unusual rheological behaviors of the wormlike micelles in a solution under shear flow.

    更新日期:2018-11-28
  • Tailored N-doped Porous Carbon Nanocomposites through MOF Self-Assembling for Li/Na ion batteries
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-27
    Cheng Chen, Mengqiang Wu, Ziqiang Xu, Tingting Feng, Jian Yang, Zhi Chen, Sizhe Wang, Yuesheng Wang

    Presently, carbon-based anodes for energy storage, such as graphite for lithium-ion batteries (LlBs) and hard carbon for sodium-ion batteries (SlBs), have low capacity and poor rate properties. However, the capacity and rate capability of these anodes can be improved via morphological control, doping and using nanostructures. In this report, a series of self-assembled N-doped porous carbon nanocomposites (NPCNs) were prepared via pyrolysis of metal-organic frameworks (MOFs)-ZIF-8/carbon nanocomposites grown on various carbon frameworks (1D CNT and/or 2D rGO). It was found that the NPC-CNT@G electrode significantly exhibits superior performance for lithium/sodium storage among the other NPCNs. NPC-CNT@G electrode delivers high initial reversible capacities (986 mAh·g-1 at 0.1 A·g-1 in LIBs; 315 mAh·g-1 at 0.05 A·g-1 in SIBs), excellent rate properties (443 mAh·g-1 at 5 A·g-1 in LIBs; 174 mAh·g-1 at 1 A·g-1 in SIBs) and durable cycle life (99% capacity retention after 2,000 cycles at 5 A·g-1 in LIBs, 80 % capacity retention after 300 cycle at 1 A·g-1 in SIBs). This ‘carbon-on-carbon’ approach described herein can be applied to make other interesting structures for high performance battery materials.

    更新日期:2018-11-28
  • Nonlinear Electrokinetic Motion of Electrically Induced Janus Droplets in Microchannels
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-27
    Mengqi Li, Dongqing Li

    The nonlinear electrokinetic motion of electrically induced Janus droplets (EIJDs) in a microchannel is studied in this paper. The EIJDs were fabricated by operating the positively charged aluminum oxide nanoparticles to partially cover the oil droplets with electric field. The nanoparticle coverage of the EIJDs changes with the electric field strength, which leads to the variation of the electrophoretic mobility of the EIJDs. Therefore, the electrokinetic velocity of the EIJDs in a microchannel changes nonlinearly with the electric field strength. In this research, the variations of the nanoparticle coverage under both constant and time-varying electric fields were studied. The results indicate that the nanoparticle coverage of the EIJDs decreases with the increase of the electric field strength. Based on the experimental results, an empirical equation for calculating nanoparticle coverage as a function of the electric field was derived. Under time-varying electric field, the variation of nanoparticle coverage lags behind the change of electric field, and the nanoparticle coverage changes differently under different time-varying electric fields. The experimental results of the electrokinetic motion of the EIJDs in a microchannel confirm that the electrokinetic velocity increases nonlinearly with the electric field. Due to the lag of the nanoparticle coverage, the variation of the electrokinetic velocity in a microchannel is different between the increasing and decreasing periods of the electric field.

    更新日期:2018-11-28
  • Visible-light degradation of sulfonamides by Z-scheme ZnO/g-C3N4 heterojunctions with amorphous Fe2O3 as electron mediator
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-27
    Guanglan Di, Zhiliang Zhu, Hua Zhang, Jianyao Zhu, Yanling Qiu, Daqiang Yin, Stephan Küppers

    ZnO grafted amorphous Fe2O3 matrix (ZnO/Fe2O3) was coupled with g-C3N4 to synthesize heterojunction photocatalysts with a loosened multilayered structure. The ZnO/Fe2O3/g-C3N4 exhibited enhanced photocatalytic performance in the degradation of sulfamethazine under visible-light irradiation (λ > 420 nm), with an optimum photocatalytic degradation rate approximately 3.0, 2.4 times that of pure g-C3N4 and binary ZnO/g-C3N4. Moreover, the target sulfonamides spiked in actual surface water samples could be efficiently photodegraded by ZnO/Fe2O3/g-C3N4 after 8 h of irradiation, demonstrating its practical potential. An amorphous Fe2O3-mediated Z-scheme mechanism was proposed for the charge transfer at the heterojunction surface, which involved a Fe(III)/Fe(II) oxidation-reduction center that favored the retarded charge recombination and improved photocatalytic activity. Such a mechanism was well supported by the direct detection of surface generated ·O2− and ·OH reactive species. Finally, detailed transformation pathways were proposed based on the photodegradation products identified by QToF-MS analyses. This work provides an illustrative strategy for developing efficient Z-scheme photocatalysts for water purification, by taking advantage of amorphous Fe-based oxides in the semiconductor lattice matching.

    更新日期:2018-11-28
  • CeO2 immobilized on magnetic core-shell microparticles for one-pot synthesis of imines from benzyl alcohols and anilines: support effects for activity and stability
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-24
    Yu Long, Zekun Gao, Jiaheng Qin, Peng Wang, Wei Wu, Lin Zhang, Zhengping Dong, Jiantai Ma

    Four types of core-shell materials with magnetic Fe3O4 microparticles as the core were prepared through different approaches using dopamine, glucose, tetrabutyl orthotitanate (TBOT), and tetraethyl orthosilicate (TEOS) as the shell precursor, respectively. CeO2 nanoparticles (NPs) was successfully immobilized onto these supports to fabricate efficient catalysts for the tandem catalytic synthesis of imines from benzyl alcohols and anilines at low temperature under air atmosphere. The as-prepared catalysts were detailedly characterized by TEM, EDX, XRD, FT-IR, XPS VSM, ICP, and CO2-TPD. Interestingly, these prepared catalysts showed higher catalytic activity than reported CeO2 catalysts. Most attractively, the catalyst with a shell of nitrogen-doped-carbon derived from dopamine exhibited the best catalytic property, and outstanding stability and recyclability in the cycle experiment. According to the XPS and CO2-TPD characterization, the enhanced performance of Fe3O4@CN@CeO2 composites can be attributed to two reasons as follows: (1) the immobilization of CeO2 improved its alkalinity at low reaction temperature, and alkalinity is beneficial to promote the oxidation of alcohols to benzaldehyde, which is the rate-determining step for this tandem reaction; (2) the doped nitrogen generated Lewis basic site could satisfactorily stabilize Ce3+/Ce4+ pair of CeO2, which determined the catalytic activity and stability of CeO2 based catalysts for this tandem reaction. Moreover, the prepared catalysts could be facilely recovered from the reaction mixture with an external magnet. This work may provide a useful strategy for constructing CeO2 based catalysts for green and sustainable catalysis.

    更新日期:2018-11-26
  • Anisotropic Interaction driven Surface Modulation on Spray-dried Microgranules
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-24
    Priyanka Biswas, Debasis Sen, Jae-Min Ha, Sung-Min Choi

    Rapid evaporation of solvent from spray colloidal droplets induces directed self-assembly among the nanoparticles, eventually interlocking them into correlated granular structures. In this work, it is demonstrated that anisotropy in colloidal interparticle interaction plays a key role in governing the surface topology of spray-dried granules. Colloidal dispersion comprised of spherical nanosilica (NS) and cylindrical carbon nanotubes (CNT) was chosen as a model system in this regard. For identical polarities of the colloidal components, granules with prominent wrinkle-like modulations are obtained, which is in drastic contrast with the case of opposite polarities. The extent of surface modulation depends on the relative concentration of CNT with respective to NS. A plausible mechanism for the formation of surface modulation is elucidated on the basis of the evolving anisotropic interparticle interactions during assembly. Electron microscopy, small-angle scattering, Raman spectroscopic techniques have been used for quantitative characterization of these micro-granules.

    更新日期:2018-11-26
  • The hydrophobic modification of kappa carrageenan microgel particles for the stabilisation of foams
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-24
    A.L Ellis, T. Mills, I.T Norton, A.B Norton-Welch

    Hypothesis Polysaccharides such as kappa carrageenan are often utilised in fat replacement techniques in the food industry. However, the structural role they can provide within a product is limited by their hydrophilic nature. Hydrophilic particles can be surface-activated by hydrophobic modification e.g. in-situ interaction with a surfactant. This can drastically improve foam stability by providing a structural barrier around bubble interfaces offering protection against disproportionation and coalescence. Hence, it should be possible to bind negatively charged kappa carrageenan particles with a cationic surfactant through electrostatic interaction, in order to alter their surface properties. Experiments Lauric Arginate was mixed with kappa carrageenan microgel particles at various concentrations and the potential electrostatic interaction was studied using zeta potential, turbidity and rheological measurements. Mixtures were then aerated and foaming properties explored, in particular the location of the particles. Findings Lauric Arginate was successfully bound to kappa carrageenan microgel particles. Consequently, particles were surface-activated and adsorbed at the air/water interface, as shown by optical and confocal microscopy. Foam half-life peaked at an intermediate surfactant concentration, where there was sufficient surfactant to coat particle surfaces but the concentration was low enough to prevent the formation of large aggregates unable to adsorb at the a/w interfaces.

    更新日期:2018-11-26
  • Fabrication of sliver/graphitic carbon nitride photocatalyst with enhanced visible-light photocatalytic efficiency through ultrasonic spray atomization
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-22
    Shuai Mao, Rui Bao, Dong Fang, Jianhong Yi

    A composite photocatalyst, sliver/graphitic carbon nitride/pre-treated carbon fiber paper (Ag/g-C3N4/t-CFP), has been innovatively designed and successfully fabricated by loading Ag and g-C3N4 species on t-CFP using the combined methods of thermal polymerization and improved electroless plating (IEP) through ultrasonic spray atomization (USA). A micro-droplet system, USA is able to eliminate the adverse influence of concentration gradient effectively. The samples obtained were carefully characterized in terms of morphology, phase, chemical structure, and optical performance. Results suggested that compared with the conventional electroless plating (CEP), IEP strategy could ensure a better dispersibility and smaller size of Ag nanoparticles. Accordingly, the IEP-prepared Ag/g-C3N4 photocatalyst on t-CFP (ACNT-iep) exhibited a pseudo-first-order kinetics constant 12 times higher than that of the neat g-C3N4 on t-CFP for methylene blue (MB) degradation. Photoluminescence (PL) and electrochemical impedance spectra (EIS) demonstrated a more efficient separation of photogenerated carriers in ACNT-iep at the same time. The photocatalytic activity of ACNT-iep could be maintained at a high level over five cycles.

    更新日期:2018-11-24
  • Quantifying the force between mercury and mica across an ionic liquid using white light interferometry
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-22
    S.J. Miklavcic, C. Fung

    HypothesisUnder axisymmetric conditions, changes in the thickness of the thin film between a fluid drop and a solid revealed by white light interferometry can provide information about the interaction of the bodies. Thus, in principle one can quantify the force between the surfaces using interferometric information of film thickness profile. This is needed to quantify and analyze drop-solid interactions across complex fluids such as an ionic liquid to independently characterize new surface forces.ExperimentsInterferometric fringes were obtained in experiments on the interaction between a mercury drop and mica across a film of room temperature ionic liquid. The data is analyzed using a novel formula giving the total force acting on the drop. The calculations are compared with two other approaches to estimating forces. Qualitative and quantitative differences are discussed.FindingsThis is the first report of forces measured between mercury and mica across an ionic liquid. The system is subjected to different applied electric potentials. In each case a long ranged, exponentially decaying repulsive force is found. At small separations, the system becomes unstable and the surfaces jump into contact. The comparison of force calculation methods demonstrates the superiority of the force approach proposed here.

    更新日期:2018-11-24
  • Hierarchical NiCo2S4@NiCoP core-shell nanocolumn arrays on nickel foam as a binder-free supercapacitor electrode with enhanced electrochemical performance
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-22
    Xinwei Chang, Weilong Li, Yinghong Liu, Mi He, Xinliang Zheng, Jinbo Bai, Zhaoyu Ren

    A novel hierarchical core-shell nanocolumn array, with NiCo2S4 hollow nanowire (NiCo2S4 H-NW) as the core and NiCoP nanosheet (NiCoP NS) as the shell, has been directly synthesized on nickel foam (NF) as self-supported, binder-free electrode for high-performance supercapacitors. The morphological characterizations reveal that the diameter of NiCo2S4 H-NW core is ∼100 nm and the diameter of single NiCo2S4@NiCoP core-shell nanocolumn is ∼250 nm. Through a series of electrochemical tests and the analysis of charge storage kinetics, hierarchical NiCo2S4@NiCoP/NF electrode presents high areal specific capacitance of 5.98 F/cm2 at 1 mA/cm2, outstanding rate capability (70.29 % capacitance retention with the current density increased from 1 to 50 mA/cm2) and superior cycling stability (92.94 % of original capacity is retained after 5000 cycles at 10 mA/cm2). The prominent performance of NiCo2S4@NiCoP/NF electrode could be resulted from their unique hierarchical core-shell nanocolumn structure, which could offer abundant active sites near the interface for fast electrochemical reaction, and validly avoid the collapse of internal structure for the stability of whole structure in the repeated electrochemical measurement. The novel NiCo2S4@NiCoP/NF electrode offers a new method for future electrochemical energy storage devices with high-stability.

    更新日期:2018-11-24
  • Amphiphilic bromelain-synthesized oligo-phenylalanine grafted with methoxypolyethylene glycol possessing stabilizing thermo-responsive emulsion properties
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-22
    Feng Wang, Jinwen Zhu, Tingting Yan, Xiaomei Pei, Fuming Zhang, Robert J. Linhardt

    A thermo-responsive amphiphile was developed from oligo-phenylalanine [oligo(Phe)]. The hydrophobic moiety of the amphilphile, oligo(Phe) was synthesized via reverse hydrolysis catalyzed by bromelain in dimethyl sulfoxide and dioxane solutions. The production of oligo(Phe) increased by 80.7% by screening suitable reaction conditions. The average degree of polymerization of oligo(Phe) was determined to be four by 1H NMR. By grafting with aldehyde-ended methoxypolyethylene glycol (mPEG), oligo(Phe) was converted to amphiphilic oligo(Phe)-mPEG. The surface tension of oligo(Phe)-mPEG solution increased with decreasing chain length of the mPEG moiety. Cytotoxicity studies showed oligo(Phe)-mPEGs are biocompatibile. On varying temperature, a reversible phase transition of oligo(Phe)-mPEG solutions could be observed. N-octane-in-water emulsions and 0.5% beta-carotene containing squalene-in-water emulsions stabilized by oligo(Phe)-mPEGs occurred at 25 oC but de-emulsification took place at >40 oC. Emulsification could be restored once the separated mixture cooled and re-homogenized. The emulsification/de-emulsification cycling could be repeated many times. The time required for de-emulsification decreased with elevated temperature but increased with a reduced concentration of oligo(Phe)-mPEGs and a reduction in the chain length of the mPEG moiety.

    更新日期:2018-11-24
  • An efficient study to reach physiological temperature with Poly(N-isopropylacrylamide) in presence of two differently behaving additives
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-22
    Payal Narang, Pannuru Venkatesu

    Hyp**othesisThe new findings in the field of polymeric materials expanding their applications in improving the quality of health care are of primary concern. Undoubtedly, the alteration in surface properties of polymeric materials on addition of different additives may provide a step forward towards their better implications in many areas of science. In this regard, the interactions of poly(N-isopropylacrylamide) (PNIPAM) with two differently behaving additives may lead to a new method to carry the phase transition temperature of PNIPAM more near to body temperature so that it can be easily used in drug delivery through intravenous or oral insertion.ExperimentsIndividually, the addition of sodium dodceylsulfate (SDS) and trimethylamine N-oxide (TMAO) is increasing and decreasing the lower critical solution temperature (LCST) of PNIPAM as compared to classical LCST of PNIPAM in aqueous solution, respectively. In the present study, we try to emphasis the role of mixed SDS and TMAO environment in varying ratios on the phase transition behaviour of PNIPAM. Many biophysical techniques are employed such as UV-visible spectroscopy, fluorescence spectroscopy and dynamic light scattering (DLS), Laser Raman spectroscopy technique and Field emission scanning electron Microscopy (FESEM) for this part of work.FindingsThe SDS is observed to form globules with PNIPAM segments and do not lead to turbidity of solution for the concentration greater than 10 µM. The negatively charged SDS bound PNIPAM globules that do not allow PNIPAM to associate, however; TMAO leads to turbid solution resulted from the hydrophobic association of PNIPAM. SDS is found to be very effective in increasing the LCST up to 62.8 0C even at very low (7.5 mM) concentration as compared to decreasing efficiency of TMAO where LCST reaches up to 29.4 0C for 0.75 M however, their mixture in specified concentration (1 mM SDS and 0.1 M TMAO) can bring the LCST of PNIPAM very near to body temperature (i.e. ∼ 36 0C) that is quiet promising for its use in target delivery engineering. TMAO ability to counteract the adverse effect of SDS is the main core reason in getting LCST near to body temperature.

    更新日期:2018-11-24
  • Sandwich Layering in Binary Nanoparticle Films and Effect of Size Ratio on Stratification Behavior
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-23
    Weiping Liu, Amanda J. Carr, Kevin G. Yager, Alexander F. Routh, Surita R. Bhatia

    HypothesisStratification or self-segregation of multicomponent particle mixtures during drying is an important phenomenon to understand for the development of single-step deposition processes for complex coatings. We hypothesize that varying the ratio of particle Peclet numbers will lead to different types of stratification behavior.ExperimentsBinary colloidal films of polystyrene and silica were prepared by evaporative film formation, and stratification of nanoparticles of different size ratio (7.7 – 1.2) was studied using microbeam small-angle X-ray scattering (SAXS).FindingsSAXS spectra showed noticeable variations at different film depths, consistent with stratification. These results are quantified to obtain vertical composition profiles. We observe “sandwich”-type layered structures at different nanoparticle size ratios, which to our knowledge have not been previously observed experimentally or predicted by theory. For example, for films of larger particle size ratios (7.7∼4.8), large particles are enriched at the film top and bottom, leading to a large-small-large or “LSL” behavior; while within films of smaller particle size ratio (2.2∼1.2), small particles are enriched at the top and bottom of the film (small-large-small or “SLS” structures). The enrichment of particles at the top persists over several hundred particle layers and is not just a single monolayer pinned to the upper surface.

    更新日期:2018-11-24
  • Gravity-driven catalytic nanofibrous membrane with microsphere and nanofiber coordinated structure for ultrafast continuous reduction of 4-nitrophenol
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-23
    Jianwei Wang, Xiaoqiang Pei, Ge Liu, Jianfeng Bai, Yajie Ding, Jianqiang Wang, Fu Liu

    Silver loaded nanofibrous membrane with high catalytic performance for 4-nitrophenol under continuous gravity-driven filtration was developed in this study. A polydopamine (PDA) microsphere and nanofiber coordinated composite structure was fabricated through an in situ PDA synthesis to achieve a high catalyst loading and controllable residence time of 4-nitrophenol. The incorporated PDA microspheres played an important role for the enhancement of catalytic performance due to the increased surface area (23% increase compared with PAN and PAN-PDAs-Ag) and reduced membrane porosity. Silver loading amount and the residence time of 4-nitrophenol was increased by more than 108% (from 1.2 wt% to 2.5 wt%) and 45% (from 0.79 s to 1.15 s) when comparing with PAN-PDAc-Ag and PAN-PDAs-Ag nanofibrous membrane. The conversion rate of 4-nitrophenol in a gravity-driven filtration process was as high as 97% when PAN-PDAs-Ag nanofibrous membrane was used, which was much higher than the PAN-PDAc-Ag membrane (80%). In addition, the PAN-PDAs-Ag nanofibrous membrane exhibited excellent recycle performance, the conversion rate was maintained as high as 93% after five times of reuse. The microsphere and nanofiber coordinated structure with enhanced surface area and controllable residence time of contaminants proposed in this study might advance the real applications of electrospun nanofibrous membrane for catalytic removal of contaminants.

    更新日期:2018-11-24
  • Magnetic natural composite Fe3O4-chitosan@bentonite for removal of heavy metals from acid mine drainage
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-23
    Guorui Feng, Jianchao Ma, Xiaopeng Zhang, Qingfang Zhang, Yuqiang Xiao, Qingliang Ma, Shaobin Wang

    Magnetic Fe3O4-chitosan@bentonite (Fe3O4-CS@BT) composites using natural materials were synthesized and used to remediate acid mine drainage (AMD) for heavy metal removal. It was found that the composites had a good magnetism, high stability and good performance in removal of Cr(VI) in the synthetic aqueous solutions. The thermodynamic parameters showed that Cr(VI) adsorption onto Fe3O4-CS@BT was an exothermic and spontaneous process. The adsorption kinetics was well described by a pseudo-second-order model, and the adsorption isotherms fit the Langmuir model with a maximum adsorption capacity of 62.1 mg/g at 25 oC. Solution pH was a key factor for adsorption and the optimized pH was 2.0. Fe3O4-CS@BT could be easily recycled through an external magnetic field and the adsorption capacity reduced by only 3% after five consecutive adsorption–desorption processes. In addition, Fe3O4-CS@BT was found to be an excellent adsorbent for actual AMD remediation containing Cd, Cr, Cu, Fe Zn, Ni and Pb, suggesting that the Fe3O4-CS@BT was an effective and economical adsorbent for the treatment of AMD.

    更新日期:2018-11-24
  • Spherical Mesocrystals from Self-assembly of Folic Acid and Nickel(II) Ion for High-performance Supercapacitors
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-23
    Jing Zhao, Qin Li, Lei Han, Rui Liu

    The formation of spherical mesocrystalline microparticles (FA-Ni) was achieved through the self-assembly between folic acid and nickel ions. Such favorable structure and the existence of abundant active sites within FA-Ni were responsible for the high specific capacitance (912 F g−1 at 0.5 A g−1) and energy density (27.81 Wh kg-1) of the material when used as a supercapacitor. Meanwhile, the as-synthesized FA-Ni showed excellent stability (97.6 % capacitance retention over 8000 cycles at 10 A g-1). This facile method would be expected to benefit for the preparation of mesocrystals based on biological ligands and their use as the promising electrode materials for high performance supercapacitors.

    更新日期:2018-11-24
  • An Acid-Pasting Approach Towards Perylenetetracarboxylic Diimide Based Lithium/Sodium Ion Battery Cathodes with High Rate Performances
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-23
    Dongqing Wu, Fan Jing, Xin Xi, Lie Ma, Deng Lu, Peng Yang, Ruili Liu

    An acid-pasting approach is developed in this work to fabricate the composite of perylenetetracarboxylic diimide (PTCDI) and carbon black in concentrated sulfuric acid. Different from traditional mechanical mixing, the solution-based fabrication strategy enables the sufficient blending of PTCDI as active component and carbon black as conductive agent in the PTCDI/CB composite. Serving as the cathode material, the PTCDI/CB composite shows excellent electrochemical performances in both lithium ion battery (137 mAh g-1 at 100 mA g-1 and 110 mAh g-1 at 2000 mA g-1) and sodium ion battery (134 mAh g-1 at 100 mA g-1 and 99 mAh g-1 at 1000 mA g-1), which are comparable to the state-of-art organic/inorganic cathode materials. Considering the simplicity of the processing procedures and the low cost of the starting materials, the acid-pasting approach is a highly attractive method for the solution-based manufacturing of organic secondary battery electrodes.

    更新日期:2018-11-24
  • Bioinspired crystallization, sensitized luminescence and cytocompatibility of citrate-functionalized Ca-substituted europium phosphate monohydrate nanophosphors
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-23
    Jaime Gómez-Morales, Cristóbal Verdugo-Escamilla, Raquel Fernández-Penas, Carmen Maria Parra-Milla, Christophe Drouet, Michele Iafisco, Francesca Oltolina, Maria Prat, Jorge Fernando Fernández-Sánchez

    Biocompatible nanosystems exhibiting long-lifetime (∼millisecond) luminescence features are particularly relevant in the field of bioimaging. In this study, citrate-functionalized calcium-doped europium phosphates nanophosphors of the rhabdophane type were prepared at different synthesis times by a bioinspired crystallization route, consisting in thermal decomplexing of Ca2+/Eu3+ /citrate/phosphate/carbonate solutions. The general formula of this material is CaαEu1-α(PO4)1-α(HPO4)α·nH2O, with α ranging from 0 to 0.58 and n∼1. A thorough characterization of the nanoparticles has been carried out by XRD (including data processing with Topas 6.0), HR-TEM, TEM, FTIR, TG/DTA, ICP, dynamic light scattering (DLS), electrophoretic mobility, and fluorescence spectroscopy. Based on these results a crystallization mechanism involving the filling of cationic sites with Ca2+ ions associated to a concomitant adjustment of the PO4/HPO4 ratio was proposed. Upon calcium doping, the aspect ratio of the nanoparticles as well as of the crystalline domains decreased and the relative luminescence intensity (R.L.I.) could be modulated. Neither the pH nor the ionic strength, nor the temperature (from 25 to 37 °C) affected significantly the R.L.I. of particles after resuspension in water, leading to rather steady luminescence features usable in a large domain of conditions. This new class of luminescent compounds has been proved to be fully cytocompatible relative to GTL-16 human carcinoma cells and showed an improved cytocompatibility as the Ca2+ content increased when contacted with the more sensitive m17.ASC murine mesenchymal stem cells. These biocompatible nanoparticles thus appear as promising new tailorable tools for biomedical applications as luminescent nanoprobes.

    更新日期:2018-11-24
  • Fabrication of Co3O4 NPs-graphene oxide nanocomposites as an efficient catalyst towards oxygen reduction and its catalytic applications
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-23
    Wenjuan Lv, Wenjie Qin, Yonglei Chen, Xingguo Chen

    Co3O4 nanoparticles-graphene oxide (Co3O4 NPs-GO) nanocomposites with good solubility were successfully synthesized and well characterized. As a nanocatalyst with oxidase-mimicking activity, the nanocomposites can catalyze the oxidation of 3′,5,5′-tetramethylbenzidine (TMB) with high efficiency. The catalyzing reaction was rapid and no extra H2O2 was needed compared with other similar TMB oxidation reactions. The catalyzing reaction mechanism of the system was investigated in detail. And it was demonstrated that the oxygen involved in the reaction came from the oxygen absorbed on the nanocomposites which oxidized TMB. Based on this reaction, a colorimetric system for vitamin C detection in vegetable and fruits was established. Under the optimum conditions, the detection can be achieved within 10 min and a linear relationship in concentration range of 2.5×10-6~1.8×10-5 M and 3.4×10-5~1.7×10-4 M was obtained with a detection limit of 7.0×10-7 M. The colorimetric system exhibited good selectivity, sensitivity and satisfactory recoveries ranged from 93.1% to 101.1%.

    更新日期:2018-11-24
  • Type II heterojunction in hierarchically porous zinc oxide/graphitic carbon nitride microspheres promoting photocatalytic activity
    J. Colloid Interface Sci. (IF 5.091) Pub Date : 2018-11-20
    Sijia Wu, Hong-Juan Zhao, Chao-Fan Li, Jing Liu, Wenda Dong, Heng Zhao, Chao Wang, Yang Liu, Zhi-Yi Hu, Lihua Chen, Yu Li, Bao-Lian Su

    Graphitic carbon nitride (g-C3N4) is a visible light active semiconductor. However, low conductivity and high recombination rate of photogenerated electrons and holes limit its application in photocatalysis. In this work, we design and synthesize hierarchically porous zinc oxide/ graphitic carbon nitride (ZnO/g-C3N4) microspheres with type-II heterojunction to effectively degrade rhodamine B (RhB) via increasing the charge-separation efficiency. The ultraviolet-visible (UV-Vis) absorption spectra, Mott-Schottky plots and valence band X-ray photoelectron spectroscope confirm the formation of type-II heterojunction between ZnO nanocrystals and g-C3N4 nanosheets. As a result, the 1.5-ZnO/g-C3N4 composite (the mass ratio of zinc acetate dihydrate to g-C3N4 is 1.5) exhibits the highest photocatalytic activity with good stability and higher photocatalytic degradation rate comparing to pure g-C3N4 and pure ZnO. In addition, our results confirm that •O2- and h+ are the main active species for ZnO/g-C3N4 in degradation of RhB.

    更新日期:2018-11-21
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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