Highly sensitive and rapid biosensing on a three-dimensional polymer platform Polym. J. (IF 2.145) Pub Date : 2018-04-20 Madoka Takai
Increasing sensitivity and decreasing assay time are two of the most crucial goals in the development of biosensing devices, such as immunoassays, protein electrophoresis, and bioimaging nanoprobes. We have developed three-dimensional (3D) nano/microstructured platforms for biosensing devices aimed at highly sensitive and rapid immunoassays. One such platform is a nanosphere structure with poly[2-methacryloyloxyethyl phosphorylcholine-co-n-butyl methacrylate-co-p-nitrophenyloxycarbonyl poly(ethylene glycol) methacrylate] (PMBN) prepared by the electrospray deposition (ESD) method. Compared with flat PMBN, the 3D nanosphere surface enables the immobilization of a large amount of antibody to enhance the specific signal of the immunoassay. Furthermore, PMBN is resistant to non-specific protein adsorption. Thus, this 3D nanosphere structure can be applied in microchip environments, leading to highly sensitive and rapid immunoassays. To obtain a more rapid assay that takes at most 5 min, we utilized another platform: a 3D polystyrene (PS) microfiber structure prepared by ESD paired with vacuum pump pressurization to induce bulk flow. This system takes advantage of the increased amount of antibody immobilized on the 3D microfiber and the accelerated propagation of antigens through the microfiber induced by the vacuum pump to enable an efficient and rapid immunoassay.
Liquid-crystalline behavior and ion transport properties of block-structured molecules containing a perfluorinated ethylene oxide moiety complexed with a lithium salt Polym. J. (IF 2.145) Pub Date : 2018-04-18 Taira Onuma, Masafumi Yoshio, Masaki Obi, Kimiaki Kashiwagi, Shinya Tahara, Takashi Kato
The liquid-crystalline behavior of fluorinated block-structured molecules and the ion transport properties of their complexes with a Li salt have been examined. The block-structured molecules comprise a perfluorinated oligo (ethylene oxide) moiety containing a terminal methyl carbonate or a terminal hydroxyl group and an octadecyl moiety. These molecules exhibit highly ordered smectic phases. The fluorinated molecule with a terminal methyl carbonate possesses an isotropization temperature lower than that of the analogous non-fluorinated molecule. The fluorinated molecule complexed with a Li salt shows ionic conductivities on the order of 10−6 S cm−1 in the smectic phase formed at ambient temperature, while conductivities on the order of 10−5 S cm−1 are observed in the isotropic phase.
Preparation of nano- and microstructures through molecular assembly of cyclic oligosaccharides Polym. J. (IF 2.145) Pub Date : 2018-04-17 Hajime Shigemitsu, Toshiyuki Kida
The shape, size, and size distribution of nano- and microstructures formed by the self-assembly of small molecules are crucial factors that govern their chemical and physical properties. Understanding these factors can reveal the correlations between the supramolecular structure and the emergent properties and may realize innovative new materials. Hence, the formation processes and syntheses of nano- and microstructures consisting of various functional molecules have been actively studied. Herein, we report the bottom-up preparation and functions of nano- and microstructures formed by the self-assembly of cyclodextrins (CDs), which are cyclic oligosaccharides. Reprecipitation and electrospinning methods produce various supramolecular structures based on CDs. The assembly modes of CD molecules and their morphologies remarkably affect the properties and functions of the supramolecular structures. In particular, γ-CD-based supramolecular structures achieve the inclusion of guest molecules dissolved in oils, which is difficult to achieve with a single-CD molecule. Furthermore, cubic γ-CD structures show excellent dispersibility in oils, forming organogels in various oils, and organic solvents at ambient temperature. These studies indicate that the construction and morphological control of self-assembled CD structures can effectively realize the potential function of CD molecules and open new fields in oligosaccharide chemistry and supramolecular chemistry.
Mesomorphic glass-forming ionic complexes composed of a cholesterol phthalate and 1-Cn-3-methylimidazolium: phase transition and enthalpy relaxation behavior Polym. J. (IF 2.145) Pub Date : 2018-04-12 Itaru Nakajima, Taishi Kitaguchi, Kazuki Sugimura, Yoshikuni Teramoto, Yoshiyuki Nishio
Ionic complexes consisting of a mesogenic cholesterol derivative and 1-alkyl (Cn)-3-methylimidazolium (CnMim) (n = 6–18) were prepared from ethanol solutions containing an equimolar mixture of cholesterol hydrogen phthalate (CHP) and 1-Cn-3-methylimidazolium hydroxide; the imidazolium hydroxide was obtained by anion exchange of 1-Cn-3-methylimidazolium bromide. The complex samples, termed [CnMim][CHP], were examined to evaluate their thermal transition patterns. Excluding the two samples (n = 6, 8) that showed no definite ordered phase, the complexes with n ≥ 10 formed a cholesteric (n = 10, 12) or smectic (n = 14–18) mesophase in a considerably wide range of temperatures; this wide range reflects the additional thermotropic property of the salts of CnMim with longer alkyl chains. These fluid mesophases transformed into a mesomorphic vitreous solid without crystallization in a usual cooling process. For the glassy mesomorphic samples of selected complexes (n = 10, 18), the enthalpy relaxation behavior was followed as a function of the aging temperature and time, and the data were analyzed in terms of a Kohlrausch–Williams–Watts (KWW) type of stretched exponential equation. A very narrow distribution of relaxation times was observed for the “liquid crystalline glasses”, indicating the high uniformity of the relaxation mode.
Direct arylation polycondensation as conjugated polymer synthesis methodology Polym. J. (IF 2.145) Pub Date : 2018-04-09 Kazuhiro Nakabayashi
Direct arylation polymerization (DArP), which is a cross-coupling polymerization between a dihaloarene monomer and a non-substituted arene monomer, has attracted widespread attention for conjugated polymer synthesis. In DArP, no prior preparation of arene monomers with organometallic functionalities is necessary, in contrast to typical cross-coupling polymerizations such as the Suzuki and Stille reactions. Furthermore, the low toxicity of the byproducts of DArP contributes to green chemistry. In terms of efficiency and environmental friendliness, these advantages make DArP an attractive next-generation polymer synthetic method. To date, numerous conjugated polymers have been synthesized by DArP. However, many problems remain to be overcome, including better understanding of the correlation between polymer structure and DArP factors, the design of a more efficient DArP system, and so on. Addressing these problems could lead to the establishment of DArP as a viable alternative for conjugated polymer synthesis. We revealed that a variety of conjugated polymers such as donor–acceptor alternating copolymers (arylene diimide-based donor–acceptor alternating copolymers and thienoisoindigo-based donor-acceptor alternating copolymers) and regioregular poly(3-alkylselenophene)s were successfully synthesized by the DArP strategy based on appropriate molecular design and adjustment of the catalytic system. This focus review will describe our recent studies developing the synthesis of novel conjugated polymers via DArP.
Cellular behaviors on polymeric scaffolds with 2D-patterned mechanical properties Polym. J. (IF 2.145) Pub Date : 2018-04-06 Shinichiro Shimomura, Hisao Matsuno, Yohei Kinoshita, Satoshi Fujimura, Keiji Tanaka
We propose a novel concept for cellular scaffolds with 2D-patterned mechanical properties. Thin films of glassy polystyrene (PS) with thicknesses ranging from 100 nm to 1 μm were prepared on epoxy resin-based line and space (L&S) patterned substrates. Although the outermost surface of PS on the L- and S-regions was sufficiently flat at the same level, the mechanical responses differed depending on the presence of the underlying resin foundation. The initial cell adhesion and spreading and the proliferation on the scaffolds were affected by the 2D-patterned mechanical properties, that is, cellular behavior was suppressed on mechanically unstable S-regions.
Logic gate aggregation of poly(N-isopropylacrylamide) nanogels with catechol substituents that respond to body heat Polym. J. (IF 2.145) Pub Date : 2018-04-04 Shingo Tamesue, Shinji Abe, Takuo Endo, Takeshi Yamauchi
Smart hydrogel materials are a popular topic of investigation because they have the potential to be used as smart drug carriers and soft actuators. Hydrogel materials showing responsiveness to logic gate-type stimuli are of special interest because their responsiveness can be regulated more accurately than that of common stimuli-responsive materials. In this study, poly(N-isopropylacrylamide) nanogels containing catechol substituents in their polymer network structure were prepared via precipitation polymerization. The prepared nanogels showed AND-type logic gate thermal aggregation behavior. The possible use of this logic gate-type smart nanogel aggregating system was investigated in a smart valve system.
Molecular weight-dependent physisorption of non-charged poly(9,9-dioctylfluorene) onto the neutral surface of cuboidal γ-alumina in toluene Polym. J. (IF 2.145) Pub Date : 2018-04-04 Kazuki Yamazaki, Ayako Nakao, Nozomu Suzuki, Michiya Fujiki
To understand how polymers physisorb onto solid surfaces, we investigated the physisorption behavior of non-charged, semiflexible poly(9,9-dioctylfluorene) (PF8) with three different number-average degrees of polymerization (DPn) as photoluminescent and chromophoric probes onto cuboidal γ-alumina in toluene at 5, 25, and 50 °C. PF8 revealed noticeable DPn and temperature dependencies in its physisorption behaviors. Molecular mechanics (MM)/molecular dynamics (MD) simulations [consistent valence force field (CVFF)] and Møller–Plesset second-order perturbation theory (MP2) with 6-31 G(d,p) calculations suggested that the PF8 in toluene has multiple interactions from CH/π to C–H/O interactions on the (110) surface of γ-alumina. The competition between multiple intermolecular CH/π and C–H/O interactions was crucial for the spontaneous physisorption of PF8 to occur in the presence of a solvent quantity of toluene. Calculations by time-dependent density functional theory (TD-DFT) with Becke three parameter Lee-Yang-Par (B3LYP) method and 6–31 G(d,p) basis set of a model fluorene 9-mer indicated that the π–π* absorption wavelength largely depends on the regularity of the dihedral angles between fluorene rings, while the intensity and spectral width of the π–π* absorption band are largely influenced by the regularity of the dihedral angles. Solution-phase physisorption systems are a result of the inherent nature of several competitive weak intermolecular interactions coexisting among the polymers, surface, and solvents.
Solvent-tuned dual emission of a helical poly[3,5-bis(hydroxymethyl)phenylacetylene] connected with a π-conjugated chromophore Polym. J. (IF 2.145) Pub Date : 2018-03-30 Zhichun Shi, Giseop Kwak, Young-Jae Jin, Masahiro Teraguchi, Toshiki Aoki, Takashi Kaneko
For THF solutions of an optically active helical poly[3,5-bis(hydroxymethyl)phenylacetylene] derivative bearing a biphenyl group, photoexcitation of the terphenyl moiety at 300 nm led to photoluminescence at 390 nm. On the other hand, the photoluminescence resulting from excitation at 280 nm caused dual emission at 310 and 390 nm, whose intensities were tuned by the polar-solvent stimuli which induced the collapse of the intramolecular stack structure of the side groups, and the change in the emission wavelength accompanied disappearance of the optical activity.
Studies on the phase transition of hydrogels and aqueous solutions of thermosensitive polymers Polym. J. (IF 2.145) Pub Date : 2018-03-26 Hiroyuki Kojima
In this review, our recent studies on the phase transition of hydrogels and aqueous solutions of thermosensitive homopolymers and copolymers are briefly summarized. On the basis of the concept of cooperative hydration, which is defined as the association-dissociation of water molecules bound to a polymer chain with a positive correlation between adjacent bound water molecules, we theoretically examine the following phenomena: (i) the high-temperature collapse of poly(N-isopropylacrylamide) (PNIPAM) gels in water; (ii) the reentrant volume phase transition of PNIPAM gels in mixed solvents of water/methanol; (iii) the temperature dependence of the swelling behavior of PNIPAM microgels in mixed solvents of water/methanol, the selective solvent adsorption of the gels and the selective solvent binding to the polymer chains; and (iv) the nonlinear depression of the lower critical solution temperature of thermosensitive copolymers in water as the monomer composition is varied. Our theoretical results are compared with the experimental data, and the molecular mechanisms are discussed.
Responsibility of lipid compositions for the amyloid ß assembly induced by ganglioside nanoclusters in mouse synaptosomal membranes Polym. J. (IF 2.145) Pub Date : 2018-03-22 Teruhiko Matsubara, Takahiro Kojima, Ryoto Fukuda, Kazutoshi Iijma, Miwa Hirai, Naoki Yamamoto, Katsuhiko Yanagisawa, Toshinori Sato
The assembly of amyloid ß protein (Aß) on ganglioside-enriched microdomains in presynaptic neuronal membranes is involved in the onset of Alzheimer’s disease. We previously found that a highly enriched ganglioside domain generated in a reconstituted lipid bilayer composed of synaptosomal lipids functioned as an Aß-sensitive ganglioside nanocluster (ASIGN) that may induce a spherical Aß assembly. In the present study, the major lipid components of a detergent-resistant membrane microdomain (DRM) fraction of synaptosomes prepared from an aged mouse brain were identified, and we demonstrate that the proportion of Aß-insensitive gangliosides such as GM3 directly affects the Aß assembly in synaptosomal membranes. Liquid chromatography coupled to mass spectrometry analyses indicated that ganglio a-series gangliosides (GM1, GM2, GM3, and GD1a) were abundant in DRM fractions. In addition, the GM3/GM1 ratio and the cholesterol content in the synaptosomal fraction differed from those in the non-synaptosomal fraction, in which GM1 and GM3 are sensitive and insensitive gangliosides, respectively. The highly enriched ganglioside nanocluster was identified by the surface topography of ternary mixed lipid bilayers composed of gangliosides, sphingomyelin, and cholesterol. Our results indicate that the composition of gangliosides is responsible for the characteristics of the nanocluster generated in the presynaptic neuronal membranes.
Reversible temperature-responsive and lectin-recognizing glycosylated block copolymers synthesized by RAFT polymerization Polym. J. (IF 2.145) Pub Date : 2018-03-20 Tomonari Tanaka, Masaru Okamoto
Reversible temperature-responsive and lectin-recognizing glycosylated block copolymers composed of polyacrylamide (PAAm) and poly(N-isopropylacrylamide) (PNIPAm) were synthesized by consecutive RAFT polymerization reactions. PAAm bearing maltose moieties was synthesized by RAFT polymerization with a trithiocarbonate derivative as a chain transfer agent for chain extension and with N-isopropylacrylamide to obtain block copolymers. The resulting glycosylated block copolymers were responsive to temperature at approximately 33 °C (lower critical solution temperature; LCST) and formed aggregates 100 nm in diameter in aqueous media above the LCST. The aggregates specifically interacted with lectin in aqueous media above the LCST, forming conjugates. When the temperature was decreased below the LCST, the conjugate dissociated into the aqueous medium. The conjugates of block copolymer and lectin were reversible in response to changes in temperature.
In situ synthesis of easily separable Au nanoparticles catalysts based on cellulose hydrogels Polym. J. (IF 2.145) Pub Date : 2018-03-20 Xiaobo Lin, Xing Han, Jiahao Wang
Cellulose hydrogels are “green” reductants and supports for Au nanoparticles (Au NPs). Herein, we report a facile method for synthesizing Au NPs based on alkali/urea regenerated cellulose hydrogels. By controlling the precursor concentration and the reaction temperature, the size of the Au NPs can be adjusted. We successfully demonstrate that the Au NP/cellulose hydrogels can be used as efficient heterogeneous catalysts in the reduction of 4-nitrophenol (4-NP). Au NPs with smaller sizes have higher catalytic activity. The highest turnover frequency (TOF) of the Au NPs/cellulose hydrogels is 19.4 h−1. The Au NP/cellulose hydrogels can be easily isolated after the catalytic reaction.
Multiamine-induced self-healing poly (Acrylic Acid) hydrogels with shape memory behavior Polym. J. (IF 2.145) Pub Date : 2018-03-19 Jun Lan, Xiuquan Ni, Chuanzhuang Zhao, Qiao Liu, Chongyi Chen
In this work, a versatile and simple strategy for building self-healing hydrogels with tunable mechanical properties and shape memory behavior is reported. A commercially available small molecule with three amino groups, diethylenetriamine (DETA), is applied to crosslink poly (acrylic acid) (PAAc) chains via ionic bonding, and the complexes of the PAAc chains with DETA form hydrophobic microdomains in the hydrogel network. The cooperation of ionic bonding and hydrophobic interactions drastically improves the mechanical properties, which can be modulated by adjusting the molar ratio of PAAc to DETA. Due to the physical interaction of the crosslinks, the hydrogels can self-heal rapidly in ambient conditions. The thermal responsiveness of the physical microdomain crosslinks endow the hydrogels with shape memory behavior. It is hoped that this novel strategy will provide new opportunities for the design of high-strength hydrogels with variable functionalities for a wide range of applications, such as artificial muscle and skin.
Tissue-engineered scaffold based on carboxymethyl chitin or chitosan for corneal epithelial transplantation Polym. J. (IF 2.145) Pub Date : 2018-03-16 Tong Li, Ye Liang, Zheying Wang, Wenhua Zhang, Liping Wang, Quan Zhou, Wenhua Xu
Blend membranes based on polysaccharides are used in tissue engineering. In this study, six groups of blend membranes were prepared with carboxymethyl chitosan (CMCTS) or carboxymethyl chitin (CMCT) as the main ingredient, blended with gelatin (Gel) and potassium acetate (KAc). Then, each group was screened and evaluated for light transmission, microstructure, and compatibility with corneal epithelial cells. The results showed that the CMCTS-Gel blend membrane (#1) and the CMCT-Gel blend membrane (#4) (volume ratio of 20:1), which had high transmittance and good surface properties, were more suitable for cell growth. Although the primary corneal epithelial cells (CECs) seeded on both blend membranes maintained marker protein expression and did not undergo cell fibrosis, the CECs on the CMCT-Gel blend membrane (#4) maintained the original epithelial morphology and showed substantially improved K12 protein levels. Studies on the potential mechanism of the anti-fibrosis effect also showed that both membranes could block the phosphorylation of Smad2 and Smad3. In addition, the CMCT-Gel blend membrane (#4) could depress the total expression of native Smad2 and Smad3.This study provides a potential corneal epithelial scaffold that will be applied in corneal epithelial reconstruction based on tissue engineering methods.
Supramolecular gel electrophoresis Polym. J. (IF 2.145) Pub Date : 2018-03-15 Masamichi Yamanaka
Amphiphilic C3-symmetric tris-ureas self-assemble into supramolecular hydrogels in aqueous solution. These supramolecular hydrogels were used as matrices for the electrophoresis of biopolymers such as proteins and nucleic acids. A unique separation mode in comparison to that of typical sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS–PAGE) was found during the electrophoresis of denatured proteins. Native proteins were separated on the basis of their isoelectric points and retained their activities. Affinity electrophoresis was realized by exploiting interactions between gelator glucosides and carbohydrate-binding proteins. Protein samples were efficiently recovered through an extremely simple operation, and up to 50% of the protein was extracted by centrifugation, which is a remarkable feature of electrophoresis using supramolecular hydrogels. Large DNA fragments that previously had been separated only by pulsed-field gel electrophoresis were separated using a supramolecular hydrogel matrix and a typical continuous-field electrophoresis apparatus. In this focus review, the author summarizes the electrophoresis of proteins and nucleic acids using our developed supramolecular hydrogel matrix.
Light-driven molecular switching of atropisomeric polymers containing azo-binaphthyl groups in their side chains Polym. J. (IF 2.145) Pub Date : 2018-03-14 Fathy Hassan, Takafumi Sassa, Takuji Hirose, Yoshihiro Ito, Masuki Kawamoto
Light-driven atropisomeric polymers containing azo and binaphthyl units with a conjugated structure were designed and synthesized. The polymers exhibit a glass transition temperature higher than 75 °C with thermal stability above 280 °C and form uniform and smooth thin films without grain boundaries. The trans-cis isomerization is efficiently reversible upon alternating photoirradiation with UV and visible light or with heat. The photoisomerization of the chiral polymer results in photomodulation of the ellipticity and optical rotation ( [α]25D [ α ] D 25 ), owing to a chiroptical switching behavior. The maximum changes in the dihedral angle and [α]25D [ α ] D 25 are 21% and 700°, respectively, from the initial state owing to a photoinduced molecular twisting motion of the binaphthyl moiety. The polymer also displays photoswitchable fluorescence with a maximum at 409 nm. A photoinduced change in the refractive index of the formed film is also observed after irradiation with linearly polarized light at 532 nm according to the anisotropic molecular orientation. These results suggest that atropisomeric polymers are potential candidates for light-driven chiroptical switches.
Modification of polyethylene using side-chain crystalline block copolymer and evaluation of hydrophilicity Polym. J. (IF 2.145) Pub Date : 2018-03-09 Yuga Miho, Sho Hirai, Ryoko Nakano, Hiroshi Sekiguchi, Shigeru Yao
We synthesized side-chain crystalline block copolymer that exhibit an adsorptive interaction with polyethylene (PE) using a monomer with a long alkane side chain and a hydrophilic monomer. By coating PE with a dilute solution of these block copolymers, the PE surface can easily be endowed with hydrophilicity in a uniform manner. This method does not require a special experimental apparatus or reagents and is more viable than conventional methods in terms of energy efficiency and cost, which means it has a lower environmental impact. Based on the measured contact angle on the modified PE surface, we also evaluated the effects of copolymer concentration in the coating solution and the degree of polymerization in the functional region of the copolymer. The results suggest that the hydrophilicity of the PE surface can be controlled by adjusting these parameters.
Photosensitive engineering plastics based on reaction development patterning Polym. J. (IF 2.145) Pub Date : 2018-03-05 Toshiyuki Oyama
Photosensitive engineering plastics as typified by photosensitive polyimides are mainly used in the electronics industry to form fine patterns for uses in which they will not be removed for a long time. However, to impart photosensitivity, it is necessary to introduce a functional group into a polymer or to use a precursor polymer, which hinders further applications of these polymers. We have developed reaction development patterning (RDP) as a method of forming a fine pattern by promoting the reaction between carboxylic acid derivatives in a polymer chain and nucleophiles in a developer selectively at the exposed or unexposed area. Since engineering plastics such as polyimide and polycarbonate inherently have carboxylic acid derivative groups in their main chain, RDP can easily impart photosensitivity to a wide range of polymers, including commercially available engineering plastics. By using RDP, it is possible to form both positive- and negative-tone patterns from the same polymer. In this review, I will describe recent developments in the study of photosensitive engineering plastics by focusing on RDP.
Synthesis and high refractive index properties of poly(thiophosphonate)s Polym. J. (IF 2.145) Pub Date : 2018-03-05 Ryoyu Hifumi, Ikuyoshi Tomita
Synthesis and high refractive index properties of poly(thiophosphonate)s Synthesis and high refractive index properties of poly(thiophosphonate)s, Published online: 05 March 2018; doi:10.1038/s41428-018-0032-z Novel high-refractive-index materials consisting of poly(thiophosphonate)s were developed by the polycondensation of phenylthiophosphonic dichloride with various bisphenols. These polymers exhibit excellent thermal stability (Td5 > 420 °C), moderate to high glass transition temperatures (117–204 °C) and high transparency in the visible light region. Furthermore, they achieve high refractive indices of 1.626–1.687 owing to the highly polarizable sulfur and phosphorous atoms in their backbones and relatively high Abbe numbers of 21.3–27.5.
Inducing defects in ordered mesoporous carbons via the block copolymer-templated high-temperature carbonization of nitrogen-containing polymeric precursors Polym. J. (IF 2.145) Pub Date : 2018-03-05 Ling Gao, Alvin Chandra, Yuta Nabae, Teruaki Hayakawa
Structural defects in graphene directly influence its electronic structure and can lead to the development of unique properties. However, the introduction of defects into ordered mesoporous graphitic carbons has yet to be demonstrated. Herein, defects were successfully introduced into the graphitic carbon lattice of well-ordered hexagonal mesoporous carbons via a block copolymer soft-template method and high-temperature carbonization. Small-angle X-ray scattering, scanning electron microscopy, and nitrogen adsorption measurements revealed that well-ordered ~4 nm cylindrical mesoporous structures with high surface areas (532 m2g−1) and good mesoporosity were maintained after high-temperature carbonization up to 1500 °C and mechanical milling. Raman and CHN elemental analyses suggested that defects were introduced into the graphitic carbon lattice through surface reconstruction induced by N-atom removal during heat treatment. The obtained robust and well-ordered N-containing mesoporous carbons with deliberately introduced defects are considered promising materials for electrochemical reactions and as catalyst supports.
Preparation of temperature-responsive, cationized, poly(ε-caprolactone)-based, cross-linked materials by a macromonomer design and positive charge control on the surface Polym. J. (IF 2.145) Pub Date : 2018-02-26 Kohei Iwamatsu, Koichiro Uto, Yuta Takeuchi, Toru Hoshi, Takao Aoyagi
In this study, a convenient method to synthesize cationic macromonomers containing branched poly(ε-caprolactone) (PCL) was developed, and stable materials were derived by photo-cross-linking reactions. In fact, a bromomethyl-terminated modification was carried out at the hydroxyl end groups of the starting PCL; then, the terminal groups reacted with 2,2′-dimethylaminoethyl methacrylate to afford the objective macromonomers, which had N,N′-dimethylmethacrylamino groups at the chain ends. The resulting PCL-based materials were cross-linked by UV light irradiation and were stable against exposure to organic solvents and heating above the softening points. The surface properties of the cationic, PCL, cross-linked membrane were evaluated by measuring the zeta potentials and performing anionic dye adsorption tests using Acid Red 87. As expected, the cationic, PCL, cross-linked membrane surfaces showed a positive charge and greater dye adsorption than the naked PCL, which depended on the cationic contents and temperature. Over the softening point, the positive charge steeply increased. The morphologies of adhered human mesenchymal stem cells on the PCL materials with lower cationic contents were preliminarily observed and shown to be well dispersed. The PCL-based materials in this study could enhance cell interaction and be useful for scaffold or mechanobiology studies.
The degree of crystallinity and segmental mobility in interpenetrating spherulites of poly(butylene succinate) and poly(ethylene oxide) Polym. J. (IF 2.145) Pub Date : 2018-02-21 Takayuki Ikehara, Toshiyuki Kataoka
The influence of poly(butylene succinate) (PBS) crystals on the crystallinity of poly(ethylene oxide) (PEO) in PBS/PEO blends, which exhibit interpenetrating spherulites, was examined. The degree of crystallinity, ϕ, of each component was obtained by pulsed nuclear magnetic resonance (NMR). The value of ϕ of PBS exhibited a maximum that was larger than that of the homopolymer, whereas PEO exhibited a nearly constant ϕ throughout the composition. The dilution effect, order of crystallization, and change in the glass transition temperature upon blending were discussed as factors contributing to the ϕ. PEO exhibited an apparent secondary crystallization, where ϕ gradually increased and the mobility of the chain segments was suppressed. The secondary process of PBS, on the other hand, was nearly negligible.
Multivariate analysis of 13C NMR spectra to extract information about monomer sequences in poly(methyl methacrylate-co-benzyl methacrylate)s prepared by various polymer reactions Polym. J. (IF 2.145) Pub Date : 2018-02-21 Yuchin Hsu, Mingyeh Chuang, Tomohiro Hirano, Koichi Ute
The 13C NMR spectra of atactic copolymers of methyl methacrylate (MMA) and benzyl methacrylate (BnMA) show complicated resonance patterns due to variations in their configurational sequences and monomer sequences in the macromolecular chains. Principal component analysis (PCA) was found to be useful for extracting information regarding the chemical composition and monomer sequence from the complicated resonances of the copolymers. To assess the feasibility for monomer sequence analysis, a PCA approach was applied to the spectra of MMA-BnMA copolymers prepared by partial modification of atactic poly(benzyl methacrylate) through catalytic hydrogenolysis, acidic debenzylation, saponification, and transesterification and by two-step esterification of atactic poly(methacrylic acid) (PMAa). The analysis clearly showed the formation of highly blocky copolymers via hydrogenolysis, as well as the formation of copolymers with a somewhat alternating tendency via acidic debenzylation, saponification, and transesterification in the late processes of the reactions. The copolymers formed in early processes of these reactions were essentially random sequences. The analysis also revealed that the copolymer prepared through partial methylation of PMAa with diazomethane was a random copolymer, while the copolymer prepared through partial benzylation of PMAa with benzyl bromide was a blocky copolymer.
Gel-emulsions prepared using a low-molecular-weight gelator and their use in the synthesis of porous polymers Polym. J. (IF 2.145) Pub Date : 2018-02-19 Yudai Imasaka, Mayu Sano, Masahiro Suzuki, Kenji Hanabusa
Water-in-oil (W/O) gel-emulsions consisting of water and a monomer were successfully prepared using N-3-hydroxypropylcarbonyl-L-isoleucyl-aminooctadecane as a gelator. Low-temperature polymerization of the gel-emulsions with a redox initiator was performed to obtain the corresponding porous polymers. Furthermore, polymerization of gel-emulsions containing bifunctional monomers gave crosslinked porous PMMA-HDODA, PMMA-EGDMA, PMMA-DVB, and PSt-DVB, which were found to be mechanically robust and solvent resistant. The microstructures of the porous polymers and crosslinked porous polymers were observed by scanning electron microscopy. The adsorption capacities of the polymers toward methanol, dichloromethane, acetone, tetrahydrofuran, toluene, hexane, and kerosene were assessed and rationalized in terms of the surface microstructures of the polymers. The time courses of the adsorptions were investigated, revealing a two-step adsorption process comprising rapid permeation into the cavities of the porous polymers followed by a slow swelling step. The high water-repellency of the crosslinked porous polymers was confirmed by contact angle measurement. The reusabilities of the polymers as solvent absorbents were evaluated through repeated adsorption and drying.
Polymer coating glass to improve the protein antifouling effect Polym. J. (IF 2.145) Pub Date : 2018-02-19 Tomoko Honda, Aiko Nakao, Kazuhiko Ishihara, Yuji Higaki, Keiko Higaki, Atsushi Takahara, Yasuhiko Iwasaki, Shin-ichi Yusa
Random copolymers (P(M100-m/T m )) composed of 2-methacryloyloxyethyl phosphorylcholine (MPC), which suppresses protein adsorption, and 3-(triethoxysilyl)propyl methacrylate (MTEOS), which can be covalently fixed on a glass surface, were prepared via photoinitiated radical polymerization. When P(M100-m/T m ) was coated on a glass surface, a protein antifouling effect could be observed because of the presence of MPC units on the glass surface. To confirm the coating of the glass surface with P(M100-m/T m ) by fluorescence microscopy, pyrene-labeled P(M100-m/T m ) was also prepared. An ethanol solution of P(M100-m/T m ) was spin-coated on the glass, which was exposed to NH3 vapor to promote the reaction of the pendant triethoxysilyl groups in P(M100-m/T m ) with silanol groups on the glass. The coating of the glass with MPC was confirmed by fluorescence microscopy. The protein antifouling effects of the P(M100-m/T m )-coated glass were confirmed using fluorescence-labeled proteins. It is expected that P(M100-m/T m ) can be applied as a surface-coating agent on glass containers for protein formulations.
Microwave-assisted rapid synthesis of poly(butylene succinate): principal effect of microwave irradiation of accelerating the polycondensation reaction Polym. J. (IF 2.145) Pub Date : 2018-02-14 Ritsuko Nagahata, Takashi Nakamura, Kazuhiko Takeuchi
To determine the origin of the reaction rate acceleration in the synthesis of poly(butylene succinate) (PBS) upon microwave irradiation, we herein investigated the effect of the microwave-assisted activation of the reactants, viz. the monomers 1,4-butanediol (BD) and succinic acid (SA), and of the water produced as a by-product during the reaction. The rate of removal of the water by-product from the reaction solution was precisely measured under equivalent reaction conditions (i.e., time and temperature) using both microwave and conventional heating methods. Microwave heating selectively activated and removed the water from the reaction solution more rapidly and to a greater extent than oil bath heating. Measurement of the temperature-dependent dielectric properties of the reactants revealed that the dielectric loss factor (εʹʹ) of BD increased with increasing temperature, peaking at 80 °C. In contrast, the εʹʹ of the mixture of BD and SA was significantly lower than that of BD alone from 70–140 °C. These results indicate that the principal effect of microwave irradiation in the synthesis of PBS was the accelerated removal of the water by-product.
Metastable interface formation in isotactic poly(methyl methacrylate)/alumina nanoparticle mixtures Polym. J. (IF 2.145) Pub Date : 2018-02-13 Kazuki Matsuura, Yasuhiro Matsuda, Shigeru Tasaka
The interface structures of isotactic poly(methyl methacrylate) (it-PMMA)/alumina nanoparticle (Al2O3; ~40 nm) mixtures from tetrahydrofuran (THF) solutions were investigated by X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, and differential scanning calorimetry (DSC). The mixtures of it-PMMA can form two amorphous phases with different crystallinities depending on casting conditions from THF. These structures are metastable and have different activation energies for crystal nucleus formation. The polymer interface on Al2O3 particles changes into a crystallizable amorphous phase with a trans-gauche-rich chain conformation.
Functional polymers in nonpolar solvents induced by dissociation of macromolecular complexes Polym. J. (IF 2.145) Pub Date : 2018-02-07 Kazuki Sada
This review demonstrates our approaches for developing functional polymer systems using dissociation processes in nonpolar media. One is the molecular design of highly swellable gels known as superabsorbent polymers in nonpolar organic solvents, and the other is the supramolecular design of thermo-responsive polymers. Both of them are well documented in water, but no practical molecular design for other media have ever been proposed. For designing these behaviors, the dissociation or release of the low-molecular component from macromolecular complexes should play a key role. Therefore, controlling the dissociation processes in supramolecular chemistry should be another important strategy for developing functional polymer materials.
Self-association behavior of amphiphilic molecules based on incompletely condensed cage silsesquioxanes and poly(ethylene glycol)s Polym. J. (IF 2.145) Pub Date : 2018-02-06 Hiroaki Imoto, Ryoichi Katoh, Tomoko Honda, Shin-ichi Yusa, Kensuke Naka
Polyhedral oligomeric silsesquioxane (POSS) is an important building block for constructing organic-inorganic hybrid molecules or polymers. In this work, we report amphiphilic, incompletely condensed POSSs (IC-POSSs) possessing various substituents on the seven silicon atoms and two kinds of poly(ethylene glycol)s (PEGs) with different chain lengths. The IC-POSS cores possessed comparable thermal stability to that of the completely condensed POSS (CC-POSS) analogs, despite their open cage structure. The amphiphilic IC-POSSs formed micelles of different sizes and had polydispersity indices (PDIs) that were dependent on the substituents and the PEG chain length. Additionally, the lower critical solution temperatures (LCSTs) were observed for amphiphilic IC-POSSs possessing shorter PEG chains, while aqueous solutions of those with longer PEG chains showed high transmittance even at 80 °C.
Emergence of temperature-dependent and reversible color-changing properties by the stabilization of layered polydiacetylene through intercalation Polym. J. (IF 2.145) Pub Date : 2018-01-29 Yuya Oaki, Yukiko Ishijima, Hiroaki Imai
The stimuli-responsive color-changing properties of functional polymers are applied to the development of sensing and imaging devices. Tuning the stimuli responsivity is required for a wide range of applications. Polydiacetylene (PDA) derivatives show color changes with the application of external stimuli, such as heat and mechanical stress. Our group has focused on the layered crystal structure of PDA and its intercalation chemistry. The original layered PDA shows an irreversible color transition from blue to red upon heating to the threshold temperature. Here, we found that alkyldiamine-intercalated PDA possessed different color-changing properties, such as a higher color transition temperature and a temperature-dependent and reversible color change, than the original PDA. As the alkyl-chain length increased, the color-changing behavior gradually converted from the irreversible color transition type to the reversible temperature-dependent one. Since the intercalated diamine had a stabilizing effect on the layered structure, the stimuli responsivity varied according to the type of diamine. The results suggest that the stimuli-responsive color-changing properties of layered PDA can be finely and systematically tuned by the intercalation of organic guests.
Hydration structure of reverse osmosis membranes studied via neutron scattering and atomistic molecular simulation Polym. J. (IF 2.145) Pub Date : 2018-01-29 Tomonori Kawakami, Masaru Nakada, Harutoki Shimura, Kazuyuki Okada, Masahiro Kimura
Reverse osmosis (RO) membranes are becoming popular as energy saving and environmentally friendly materials for the desalination of water. Toward the rational design of RO membranes, we performed contrast-variation neutron scattering measurements and atomistic molecular dynamics (MD) simulations on polyamide/water systems with various water contents and deuteration ratios. The experimental and computational structure factors showed good agreement for all the systems examined. The structure of the water-rich polyamide/water system obtained from MD calculation showed that the water clusters are well connected to each other, and a relatively large number of water molecules are present at a distance over 3 Å from the polyamide. The partial radial distribution functions were calculated, and strong interactions were observed between water and the carboxyl group in polyamide. Thus, the water permeability of the RO membrane can be expected to improve when more carboxyl groups are introduced. In addition, the polyamide–polyamide interaction was found to be equal to or smaller than the polyamide–water interactions and relatively weak in the water-rich system.
Secondary crystallisation and degradation in P(3HB-co-3HV): an assessment of long-term stability Polym. J. (IF 2.145) Pub Date : 2018-01-25 Mike J. Jenkins, Kate E. Robbins, Catherine A. Kelly
The effect of long-term storage, at a range of temperatures, on the thermal and mechanical properties of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (P(3HB-co-3HV)) is reported. P(3HB-co-3HV) was stored at −22, 7, 20, 50, 75, 100, 125 and 150 °C for 672 h. Below 100 °C, the observed increase in melting point, glass transition temperature, modulus and strength are due to the development of crystallinity via a secondary process and facilitated by increasing temperature. At 125 °C, the processes of secondary crystallisation and degradation occur in parallel and there is an interplay between these processes, with the effects of degradation masked by the continuation of secondary crystallisation. At 150 °C there is a deterioration in all the properties noted above and given the reduction in molecular weight (and discolouration), this can be attributed to degradation. The significant observation from these results is that the degradation process remains active well below the melting point and long-term stability of P(3HB-co-3HV) is not only affected by secondary crystallisation, but also degradation. In addition, as no significant changes to the thermal or mechanical properties were observed during storage at −22 and 7 °C it suggests that P(3HB-co-3HV) may be a suitable packaging material for frozen or refrigerated products.
Preparation of molecularly imprinted hydrogel layer SPR sensor chips with lectin-recognition sites via SI-ATRP Polym. J. (IF 2.145) Pub Date : 2018-01-25 Rinyarat Naraprawatphong, Akifumi Kawamura, Takashi Miyata
Molecularly imprinted hydrogel layers with lectin-recognition sites were prepared on surface plasmon resonance (SPR) sensor chips via surface-initiated atom transfer radical polymerization (SI-ATRP) combined with molecular imprinting. The lectin-imprinted hydrogel layer sensor chips showed larger SPR signal change in response to a target lectin than nonimprinted hydrogel layer sensor chips. The larger SPR signal change was attributed to the strong affinity constant of the lectin-imprinted hydrogel layer for the target lectin. These results suggest that molecular recognition sites for the lectin were formed within the hydrogel layers by molecular imprinting. On the other hand, the SPR signal change of the lectin-imprinted hydrogel layer chip in the presence of other lectin was very small. Poly(2-methacryloxyethyl phosphorylcholine) as a main chain of the hydrogel layer inhibited nonspecific adsorption of other lectin. This paper describes that SI-ATRP with biomolecular imprinting is a useful method to design highly sensitive and selective SPR sensor chips with molecular recognition sites for a target lectin.
Synthesis of a near-infrared light-absorbing polymer based on thiophene-substituted Aza-BODIPY Polym. J. (IF 2.145) Pub Date : 2018-01-23 Honami Yamane, Kazuo Tanaka, Yoshiki Chujo
An alternating conjugated polymer with thiophene-substituted aza-boron dipyrromethene (BODIPY) was synthesized in which the carbon atom at the meso-position in the ligand moiety was replaced by nitrogen. Initially, it was found that the synthesized polymer had a significant near-infrared (NIR) light-absorbing ability. In the absorption spectrum, a large absorption band (molar extinct coefficient εmax = 48,000 M−1 cm−1) with a peak at 864 nm was detected in the deep NIR region, even above 1300 nm. From cyclic voltammetry (CV) data, the energy levels of the frontier orbitals were determined. Accordingly, the polymer had a deep lowest unoccupied molecular orbital (LUMO) level (−4.01 eV), and this value was similar to that of the monomer. This result indicates that extension of π-conjugation throughout the polymer main-chain influenced only the highest occupied molecular orbital (HOMO) level while preserving the LUMO.
Perpendicular orientation between dispersed rubber and polypropylene molecules in an oriented sheet Polym. J. (IF 2.145) Pub Date : 2018-01-23 Panitha Phulkerd, Yoshiaki Funahashi, Asae Ito, Shohei Iwasaki, Masayuki Yamaguchi
An immiscible blend of isotactic polypropylene (PP) and ethylene-butene-1 copolymer (EB) (PP/EB = 70/30) containing a small amount of N,N'-dicyclohexyl-2,6-naphthalene dicarboxamide as a nucleating agent for β-form crystals was prepared by T-die extrusion. We successfully prepared an extruded sheet in which the orientation of the PP molecules is perpendicular to the deformation of the EB particles, i.e., the β-form crystals of PP are predominantly oriented perpendicular to the flow direction of the sheet plane (the transverse direction, TD), whereas the EB droplets are strongly deformed in the flow direction. It should be noted that EB barely affects the crystalline form and orientation of PP. This extraordinary structure provides unique mechanical anisotropy. The tear strength of the TD sample is significantly enhanced by the anomalous crack propagation in the machine direction (MD). Moreover, the anisotropy in tensile properties, such as the Young’s modulus, yield stress, strain at break, and dynamic tensile modulus, is reduced.
Transparent and super-gas-barrier PET film with surface coated by a polyelectrolyte and Borax Polym. J. (IF 2.145) Pub Date : 2018-01-15 Mengze Lu, Sheng Huang, Shou Chen, Qing Ju, Min Xiao, Xiaohua Peng, Shuanjin Wang, Yuezhong Meng
Thin films of polyacrylic acid (PAA), 4,4‘-diphenylmethane diisocyanate (MDI) and borax were separately grown on a poly (ethylene terephthalate) (PET) film to afford a transparent film material with super gas barrier performance. Unlike electrostatic interactions or clay-loaded barrier thin films, which were easily peeled when subjected to exoteric force, excellent peel strength was obtained due to the formation of high density urethane chemical bonds. The gas vapor barrier value is dramatically decreased to the detection limit of commercial instrumentation (<0.005 cc/m2/day). These outstanding performances are attributed to the reaction between sodium metaborate and PAA, which is confirmed using online infrared radiation (IR) and X-ray photoelectron spectroscopy (XPS). The XPS of the multilayer film revealed that borax can permeate the PAA thin layer to completely crosslink the carboxyl group of PAA. The gas barrier properties are obviously improved by the permeating borax solution. In particular, compared to commercial PET film, the oxygen transmission rate (OTR) is reduced from 75 to <0.005 cc/m2/day. Moreover, the OTR value is almost same as that of poly(ethylene-co-vinyl alcohol) (EVOH) film, which is currently the best gas barrier plastic. Therefore, the PET/MDI/PAA/borax composite films show great potential for various packaging materials due to their excellent oxygen and moisture barrier characteristics, as well as other performance.
Synthesis of CO2-derived polycarbonates with high glass transition temperatures Polym. J. (IF 2.145) Pub Date : 2018-01-15 Rie Arai, Keitaro Seto, Andrew Bell, Hiroshi Sugimoto
To synthesize CO2-derived polycarbonates with high Tg values, epoxides having rigid and bulky 2-norbornyl or 1-adamantyl substituents were selected as comonomers. The alternating copolymer obtained from 1-adamantylethylene oxide showed a Tg above 150 °C. This is the highest Tg among those observed for alternating copolymers obtained from CO2 and a terminal epoxide.
Synthesis and characterization of poly(2,6-dialkoxy-1,5-naphthylene)s with low dielectric constants Polym. J. (IF 2.145) Pub Date : 2018-01-15 Li-Che Hsu, Min Chi Yang, Tomoya Higashihara, Wen-Chang Chen, Mitsuru Ueda
An efficient method to decrease dielectric constant (ε) of poly(2,6-dihydroxy-1,5-naphthylene) (PDHN) by introducing bulky alkyl side chains was reported. Poly(2,6-dialkoxy-1,5-naphthylene)s (PDANs) were prepared by the O-alkylation of PDHN with alkyl halides. The ε values of PDANs at 10 GHz decreased as the length and size of side chains increased. Especially, PDCHMN exhibited the lowest dielectric constant (ε = 2.29). The ε value results were also supported by refractive index measurement.
Synthesis, properties and structure of borafluorene-based conjugated polymers with kinetically and thermodynamically stabilized tetracoordinated boron atoms Polym. J. (IF 2.145) Pub Date : 2018-01-09 Takuya Matsumoto, Shunichiro Ito, Kazuo Tanaka, Yoshiki Chujo
Herein, borafluorene-conjugated polymers with a dibromoborafluorene monomer and various boronic acid ester comonomers are reported. By employing the Suzuki−Miyaura cross-coupling reaction, a series of copolymers was prepared with the boron atoms in tetracoordinated states. Based on comparison to the optical properties of gallafluorene copolymers, higher luminescence quantum yields were obtained from the synthesized borafluorene copolymers due to the weak spin-orbit interaction of boron compared to that of gallium. Additionally, the results from the electrochemical measurements indicated that the electron-withdrawing property of the boron atoms led to stabilization of the lowest unoccupied molecular orbitals (LUMOs) of the borafluorene copolymers. In the X-ray diffraction profiles, significant peaks originating from π−π stacking and assembly of the side chains were observed. The borafluorene copolymers were more crystalline than the gallafluorene polymers.
A facile method for the controlled polymerization of biocompatible and thermoresponsive oligo(ethylene glycol) methyl ether methacrylate copolymers Polym. J. (IF 2.145) Pub Date : 2018-01-09 Teresa Alejo, Martín Prieto, Hugo García-Juan, Vanesa Andreu, Gracia Mendoza, Víctor Sebastián, Manuel Arruebo
Photochemically controlled ATRP-like polymerization is successfully used to prepare a thermoresponsive copolymer of oligo(ethylene glycol) methyl ether methacrylate (OEGMA) and di(ethylene glycol) methyl ether methacrylate (MEO2MA). The photochemically controlled method described here provides good control over the polymer structure, architecture, and properties. This photopolymerization renders polymers with narrow molecular weight distributions (Mw/Mn = 1.3) and high monomer conversions (>90%) while using a very low iridium-based catalyst concentration (25 ppm). In addition, the reaction rate of this polymerization is fast, reaching 50% monomer conversion in less than 1 h of reaction. The lower critical solution temperature (LCST) of the prepared polymer was also adjusted to be in the range of physiological temperatures, undergoing a coil-to-globule transition at 43 °C. In addition, the resulting polymer showed no cytotoxicity on four mammalian cell lines at the highest concentration tested (0.4 mg/ml), which highlights its potential use in different biomedical applications.
Producing a magnetically anisotropic soft material: synthesis of iron oxide nanoparticles in a carrageenan/PVA matrix and stretching of the hybrid gelatinous bulk Polym. J. (IF 2.145) Pub Date : 2017-12-22 Rie Sakai, Yoshikuni Teramoto, Yoshiyuki Nishio
Abstract We propose a method for preparing magnetically anisotropic soft materials that includes chemical loading (in situ synthesis) of iron oxide nanoparticles in a matrix composed of κ-carrageenan (Car) and poly(vinyl alcohol) (PVA) followed by mechanical stretching of the hybrid in a wet process. Anionic Car was used to accommodate the iron oxide nanoparticles and was blended in advance with PVA, which has the ability of high orientation. Scanning electron microscopy revealed that the loaded granular iron oxide nanoparticles (50–100 nm) formed elliptical clusters upon stretching of the hybrid composite. Wide-angle X-ray diffraction measurements indicated that the PVA constituent was oriented in the draw direction. With the orientation of the composite matrix, the incorporated iron oxide nanoparticles gathered to form elliptical clusters. The drawn samples showed different amplitudes in the magnetization (M|| > M⊥) when measured in two setups in which the applied field was parallel (||) or perpendicular (⊥) to the draw direction. The specific responses of the drawn sheets to an external magnetic stimulus were visualized and were reasonably attributed to an effect of the magnetic anisotropy created by the preferred orientation of the nanoparticle aggregates. Graphical abstract We prepared magnetically anisotropic soft materials by in situ synthesis of iron oxide nanoparticles in a matrix composed of κ-carrageenan and PVA followed by mechanical stretching of the hybrid in a wet process. With the orientation of the composite matrix, the incorporated iron oxide nanoparticles gathered to form elliptical clusters. The drawn samples showed different magnetizations depending on the direction of magnetic field application. The specific responses were macroscopically visualized and were attributed to the magnetic anisotropy created by the preferred orientation of the nanoparticle aggregates.
Alkylated alkali lignin for compatibilizing agents of carbon fiber-reinforced plastics with polypropylene Polym. J. (IF 2.145) Pub Date : 2017-12-22 Hiroki Sakai, Kosuke Kuroda, Shiori Muroyama, Takayuki Tsukegi, Ryohei Kakuchi, Kenji Takada, Ayano Hata, Ryosuke Kojima, Tomoki Ogoshi, Masaaki Omichi, Kazuaki Ninomiya, Kenji Takahashi
As an alternative to petroleum-based compatibilizing agents, we developed lignin derivatives for compatibilizing agents of carbon fiber-reinforced plastics that have thermoplasticity. In this study, alkyl chains were introduced into alkali lignin at various ratios to optimize the compatibility of the lignin derivatives with both polypropylene and carbon fiber. The interfacial shear strength between the two materials was improved from 8.2 to 17.2 MPa by mixing with the optimized lignin derivative. The value is comparable to that achieved with a typical petroleum-based compatibilizing agent (18.3 MPa).
Synthesis of non-ionic poly(ester-sulfone) via low-temperature polycondensation for anode-selective electrophoretic deposition and subsequent photo cross-linking Polym. J. (IF 2.145) Pub Date : 2017-12-22 Yoshifumi Matsumoto, Akinori Takasu
Abstract Non-ionic aliphatic polymers containing ester and sulfonyl moieties, poly(ester-sulfones) were found to show anode-selective electrophoresis under electrophoretic deposition (EPD) conditions. Various polyesters containing a sulfide linkage were prepared via low-temperature polycondensation using scandium trifluoromethanesulfonate [Sc(OTf)3] as a catalyst in order to clarify the relationship between the chemical structure and the electrophoresis. Subsequently, oxone oxidation was carried out in order to obtain the expected saturated and unsaturated poly(ester-sulfone)s, and electrophoretic deposition (EPD) of the poly(ester-sulfone) onto stainless steel was performed. For unsaturated poly(ester-sulfone) onto stainless steel, subsequent UV irradiation cured the deposited film, improving the peeling strength of the coating. Graphical Abstract Various polyesters containing a sulfide linkage were prepared via low-temperature polycondensation using scandium trifluoromethanesulfonate [Sc(OTf)3] as a catalyst in order to clarify the relationship between the chemical structure and the electrophoresis. Subsequently, oxone oxidation was carried out in order to obtain the expected saturated and unsaturated poly(ester-sulfone)s, and electrophoretic deposition (EPD) of the poly(ester-sulfone) onto stainless steel was performed. For unsaturated poly(ester-sulfone) onto stainless steel, subsequent UV irradiation cured the deposited film, improving the peeling strength of the coating.
Enhanced self-assembly of block copolymers by surface modification of a guiding template Polym. J. (IF 2.145) Pub Date : 2017-12-19 Woon Ik Park, Young Joong Choi, Jong Min Yuk, Hyeon Kook Seo, Kwang Ho Kim
The formation of highly ordered patterns of block copolymers (BCPs) with high χ is important for next-generation lithography applications. We demonstrate here a surface-engineering methodology to enhance the self-assembly of poly(styrene-b-dimethylsiloxane) (PS-b-PDMS) BCPs with high χ by employing a hydroxyl-terminated polystyrene (PS-OH) brush. By precisely controlling the molecular weight (MW) and weight percent of PS-OH, well-ordered sub-20-nm BCP patterns were obtained over a large area in a short annealing time (<10 min) with the use of guiding templates. We systemically analyzed how the PS-OH brush affects the self-assembly kinetics of BCPs with various MWs and volume fractions. Moreover, the transmission electron microscopy (TEM) results strongly support that the PS-modulated surface plays an important role in the ordering of BCP patterns. We also achieved well-aligned 12 nm line and 18 nm dot patterns within 3 min by means of binary solvent vapor annealing at a moderate temperature under the optimum PS-OH brush conditions. These results provide a new platform for effective engineering and manipulation of the self-assembly of other BCPs for advanced BCP nanotechnologies.
3D structure of nano-oriented crystals of poly(ethylene terephthalate) formed by elongational crystallization from the melt Polym. J. (IF 2.145) Pub Date : 2017-12-14 Kiyoka Okada, Yoshitaka Tanaka, Hiroyasu Masunaga, Masamichi Hikosaka
We studied the elongational crystallization of poly(ethylene terephthalate) (PET) from the melt using polarizing optical microscope and X-ray observation. We verified that the structure and morphology discontinuously changed from conventional stacked lamellae of folded chain crystals (FCCs) to nano-oriented crystals (NOCs) when the elongational strain rate ( ε° ε ° ) exceeded a critical value of (ε°∗)≅102s−1 ( ε ° * ) ≅ 1 0 2 s - 1 . Therefore, the universality of NOC formation was verified. We found that the NOCs of PET show a novel three-dimensional (3D) structure and morphology: (i) nanocrystals (NCs) were arranged in a monoclinic lattice, which is a specific morphology for NOCs of PET, compared to iPP, and (ii) the unit cell structure of NOCs was a triclinic system with biaxial orientation. We showed the important role of the primary structure of the plate, such as a benzene ring, in the formation of a novel 3D structure and the morphology of the NOCs of PET. We also clarified that the NOCs of PET showed high performance, such as a high heat resistance temperature (Th) ≅ ≅ 281 °C, a high melting temperature (Tm) ≅ ≅ 285 °C, high maximum tensile stresses for the machine direction (MD) and transverse direction (TD) ≅ ≅ 2.8 × 102 and 74 MPa, respectively, and high Young’s moduli for MD and TD ≅ ≅ 5.4 and 1.7 GPa, respectively.
Difference in dilute aqueous solution behavior between poly(ethylene glycol) and poly(ethylene oxide) Polym. J. (IF 2.145) Pub Date : 2017-12-14 Akihisa Nakamura, Yutaka Aoki, Masashi Osa, Daichi Ida, Takenao Yoshizaki
Static light scattering behavior was examined for poly(ethylene glycol) (PEG) and poly(ethylene oxide) (PEO) of small weight-average molecular weight Mw (3 × 103−2 × 104), in methanol and water at 25.0 °C, the former polymer having hydroxy groups at both ends and the latter having a methoxy group at one end and a hydroxy group at the other. It was found that some aggregates of large size are formed in aqueous solutions of the PEO samples with Mw = 3.81 × 103 and 7.00 × 103, while all PEG and PEO samples are isolated in methanol solutions, and the PEG samples and the PEO sample of the largest Mw (=1.60 × 104) are also isolated even in the aqueous solutions. From the results of dynamic light scattering measurements for the aqueous solution of the PEO sample with Mw = 3.81 × 103 at 25.0 °C, there were detected two classes of scatterers having different sizes, i.e., the isolated chains and aggregates, the apparent hydrodynamic radius of the latter being ca. twenty times as large as that of the former.
3D-polythiophene foam on a TiO2 nanotube array as a substrate for photogenerated Pt nanoparticles as an advanced catalyst for the oxygen reduction reaction Polym. J. (IF 2.145) Pub Date : 2017-12-14 Rajashekar Badam, Raman Vedarajan, Noriyoshi Matsumi
The development of novel substrates that possess high durability, strong anchoring to catalytic metal nanoparticles and low charge transfer resistance as well as that can replace conventional carbon is of great importance. To improve the durability and reduce the cost of various energy devices, new methodologies are necessary. Therefore, we report the preparation of a macroporous hybrid material containing polythiophene electropolymerized onto TiO2 nanotubes (TNT). The prepared foam-like hybrid material exhibited a very low charge transfer resistance and was further modified with novel and green photogenerated Pt nanoparticles. The material exhibited very strong metal substrate interactions, resulting in high durability during the oxygen reduction reaction (ORR). This study proposes a novel macroporous organic/inorganic hybrid material for use as an alternative material to replace conventional carbon substrates in ORR catalysts.
Gas transport properties of polybenzoxazole–silica hybrid membranes prepared with different alkoxysilanes Polym. J. (IF 2.145) Pub Date : 2017-12-07 Tomoyuki Suzuki, Yusuke Otsuki
The gas transport properties of polybenzoxazole (PBO)–silica hybrid membranes were investigated. The PBO–silica hybrid membranes were prepared with poly(o-hydroxy amide) (PHA) as a precursor and various alkoxysilanes via thermal oxazolization and sol–gel processes. The thermal decomposition temperature of the hybrid membranes increased with increasing silica content, indicating that the thermal stability was improved by hybridization with silica. The gas permeabilities of the PBO–silica hybrid membranes also increased with increasing silica content and thermal treatment temperature. It is worth noting that the hybrid membranes prepared with tetraethoxysilane (TEOS) as the selected alkoxysilane showed simultaneous enhancements in CO2 permeability and CO2/CH4 selectivity with increasing silica content and thermal treatment temperature. The prominent CO2/CH4 separation ability of the PBO–silica hybrid membranes prepared with TEOS might be attributable to free volume holes created around the polymer/silica interfacial area and increased intermolecular chain distance, which improved size-selective CO2/CH4 separation.
In pursuit of Moore’s Law: polymer chemistry in action Polym. J. (IF 2.145) Pub Date : 2017-11-01 Hong Xu, Vasiliki Kosma, Emmanuel P Giannelis, Christopher K Ober
In pursuit of Moore’s Law: polymer chemistry in action In pursuit of Moore’s Law: polymer chemistry in action, Published online: 01 November 2017; doi:10.1038/pj.2017.64 A focused review of photoresist strategies that have been studied over the past few decades driven by the demands of Moore’s law. Selected results are discussed with emphasis on the choice of photoresist chemistry depending on the particulars of each radiation type or patterning strategy, while we present special architectures of photoresists that have attracted a great interest in the semiconductor field.
Antimicrobial cationic polymers: from structural design to functional control Polym. J. (IF 2.145) Pub Date : 2017-11-01 Yuchong Yang, Zhengguo Cai, Zehuan Huang, Xiaoyan Tang, Xi Zhang
Antimicrobial cationic polymers: from structural design to functional control Antimicrobial cationic polymers: from structural design to functional control, Published online: 01 November 2017; doi:10.1038/pj.2017.72 Antimicrobial cationic polymers mainly contain two functional components: the cationic groups and the hydrophobic groups. The antimicrobial activity is influenced by the type, amount, location and distribution of these two components. This review summarizes the structural designs of antimicrobial cationic polymers from primary to secondary structures, from covalent to noncovalent syntheses and from bulk to surface. It will provide some guidelines for developing molecular engineering of antimicrobial cationic polymers with tailor-made structures and functions.
Diels–Alder polymerization: a versatile synthetic method toward functional polyphenylenes, ladder polymers and graphene nanoribbons Polym. J. (IF 2.145) Pub Date : 2017-11-01 Ian Cheng-Yi Hou, Yunbin Hu, Akimitsu Narita, Klaus Müllen
Diels–Alder polymerization: a versatile synthetic method toward functional polyphenylenes, ladder polymers and graphene nanoribbons Diels–Alder polymerization: a versatile synthetic method toward functional polyphenylenes, ladder polymers and graphene nanoribbons, Published online: 01 November 2017; doi:10.1038/pj.2017.69 In this review, we summarize the use of Diels–Alder reaction in the synthesis of arylene-based polymers, including polyphenylenes and ladder polymers, as well as graphene nanoribbons. These polymer materials are structurally related to each other, but rarely discussed all together in a same context. The importance and versatility of the Diels–Alder polymerization is highlighted for the synthesis of such polymers with various potential applications, for example, as polymer electrolyte membrane and organic semiconductors.
Sequence-controlled polymers via reversible-deactivation radical polymerization Polym. J. (IF 2.145) Pub Date : 2017-10-25 Makoto Ouchi, Mitsuo Sawamoto
Sequence-controlled polymers via reversible-deactivation radical polymerization Sequence-controlled polymers via reversible-deactivation radical polymerization, Published online: 25 October 2017; doi:10.1038/pj.2017.66 The development of reversible-deactivation radical polymerization (RDRP) has made a great contribution not only to control of molecular weight and terminal structures but also to precise syntheses of copolymers. In particular, introducing a new concept into RDRP allows ‘sequence control’, which might lead to construction of ‘alphabet polymer’ bearing well-defined sequence like peptides in nature. Herein, some methodologies to realize sequence control based on RDRP are reviewed.
Polymers for carrying and storing hydrogen Polym. J. (IF 2.145) Pub Date : 2017-10-25 Ryo Kato, Hiroyuki Nishide
Polymers for carrying and storing hydrogen Polymers for carrying and storing hydrogen, Published online: 25 October 2017; doi:10.1038/pj.2017.70 Organic polymers for hydrogen storage and their molecular design were reviewed. Porous organic polymers reversibly stored and released hydrogen through hydrogen physisorption on their highly porous structures. Polymers containing ketone or N-heterocycle groups fixed and stored hydrogen under atmospheric pressure through the formation of chemical bonds: the hydrogenated polymers released hydrogen in the presence of catalysts at mild conditions. The advantages of the polymers enable easy handling and provide portable hydrogen-carrying materials for use in, for example, a home/on-site or pocketable hydrogen-supply system.
Polyion complex micelle formation from double-hydrophilic block copolymers composed of charged and non-charged segments in aqueous media Polym. J. (IF 2.145) Pub Date : 2017-10-25 Atsushi Harada, Kazunori Kataoka
Polyion complex micelle formation from double-hydrophilic block copolymers composed of charged and non-charged segments in aqueous media Polyion complex micelle formation from double-hydrophilic block copolymers composed of charged and non-charged segments in aqueous media, Published online: 25 October 2017; doi:10.1038/pj.2017.67 This review focuses on the physicochemical characterization of polyion complex (PIC) micelles, particularly addressing the critical molecular factors to determine the self-assembly scheme of double-hydrophilic block copolymers composed of charged and non-charged segments into micelle structures. The process of PIC micelle formation provides new insights on the block copolymer self-assembly in thermodynamically equilibrium condition in aqueous medium, such as chain length recognition and transition from uPIC, which is the PIC of smallest neutralizing unit, to PIC micelle structures.
Topology-transformable polymers: linear–branched polymer structural transformation via the mechanical linking of polymer chains Polym. J. (IF 2.145) Pub Date : 2017-10-25 Toshikazu Takata, Daisuke Aoki
Topology-transformable polymers: linear–branched polymer structural transformation via the mechanical linking of polymer chains Topology-transformable polymers: linear–branched polymer structural transformation via the mechanical linking of polymer chains, Published online: 25 October 2017; doi:10.1038/pj.2017.60 Synthesis and dynamic nature of macromolecular systems having mechanically linked polymer chains, which can undertake the topology transformation, are described. The rotaxane linking of polymer chains plays a crucial role in these systems. Successful syntheses of macromolecular rotaxane (M2R) possessing single polymer axle and one crown ether wheel made possible the development of topology-transformable polymers from star to linear. Furthermore, rotaxane-linked ABC triblock copolymer and 4-arm and 6-arm star polymers were also synthesized and transformed to other topological polymers along with the property change.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
- Acc. Chem. Res.
- ACS Appl. Mater. Interfaces
- ACS Biomater. Sci. Eng.
- ACS Catal.
- ACS Cent. Sci.
- ACS Chem. Biol.
- ACS Chem. Neurosci.
- ACS Comb. Sci.
- ACS Earth Space Chem.
- ACS Energy Lett.
- ACS Infect. Dis.
- ACS Macro Lett.
- ACS Med. Chem. Lett.
- ACS Nano
- ACS Omega
- ACS Photonics
- ACS Sens.
- ACS Sustainable Chem. Eng.
- ACS Synth. Biol.
- Acta Biomater.
- Acta Crystallogr. A Found. Adv.
- Acta Mater.
- Adv. Colloid Interface Sci.
- Adv. Electron. Mater.
- Adv. Energy Mater.
- Adv. Funct. Mater.
- Adv. Healthcare Mater.
- Adv. Mater.
- Adv. Mater. Interfaces
- Adv. Opt. Mater.
- Adv. Sci.
- Adv. Synth. Catal.
- AlChE J.
- Anal. Bioanal. Chem.
- Anal. Chem.
- Anal. Chim. Acta
- Anal. Methods
- Angew. Chem. Int. Ed.
- Annu. Rev. Anal. Chem.
- Annu. Rev. Biochem.
- Annu. Rev. Environ. Resour.
- Annu. Rev. Food Sci. Technol.
- Annu. Rev. Mater. Res.
- Annu. Rev. Phys. Chem.
- Appl. Catal. A Gen.
- Appl. Catal. B Environ.
- Appl. Clay. Sci.
- Appl. Energy
- Aquat. Toxicol.
- Arab. J. Chem.
- Asian J. Org. Chem.
- Atmos. Environ.
- Carbohydr. Polym.
- Catal. Commun.
- Catal. Rev. Sci. Eng.
- Catal. Sci. Technol.
- Catal. Today
- Cell Chem. Bio.
- Cem. Concr. Res.
- Ceram. Int.
- Chem. Asian J.
- Chem. Bio. Drug Des.
- Chem. Biol. Interact.
- Chem. Commun.
- Chem. Educ. Res. Pract.
- Chem. Eng. J.
- Chem. Eng. Sci.
- Chem. Eur. J.
- Chem. Mater.
- Chem. Phys.
- Chem. Phys. Lett.
- Chem. Phys. Lipids
- Chem. Rev.
- Chem. Sci.
- Chem. Soc. Rev.
- Chin. J. Chem.
- Combust. Flame
- Compos. Part A Appl. Sci. Manuf.
- Compos. Sci. Technol.
- Compr. Rev. Food Sci. Food Saf.
- Comput. Chem. Eng.
- Constr. Build. Mater.
- Coordin. Chem. Rev.
- Corros. Sci.
- Crit. Rev. Food Sci. Nutr.
- Crit. Rev. Solid State Mater. Sci.
- Cryst. Growth Des.
- Curr. Opin. Chem. Eng.
- Curr. Opin. Colloid Interface Sci.
- Curr. Opin. Environ. Sustain
- Curr. Opin. Solid State Mater. Sci.
- Ecotox. Environ. Safe.
- Electrochem. Commun.
- Electrochim. Acta
- Energy Environ. Sci.
- Energy Fuels
- Energy Storage Mater.
- Environ. Impact Assess. Rev.
- Environ. Int.
- Environ. Model. Softw.
- Environ. Pollut.
- Environ. Res.
- Environ. Sci. Policy
- Environ. Sci. Technol.
- Environ. Sci. Technol. Lett.
- Environ. Sci.: Nano
- Environ. Sci.: Processes Impacts
- Environ. Sci.: Water Res. Technol.
- Eur. J. Inorg. Chem.
- Eur. J. Med. Chem.
- Eur. J. Org. Chem.
- Eur. Polym. J.
- J. Acad. Nutr. Diet.
- J. Agric. Food Chem.
- J. Alloys Compd.
- J. Am. Ceram. Soc.
- J. Am. Chem. Soc.
- J. Am. Soc. Mass Spectrom.
- J. Anal. Appl. Pyrol.
- J. Anal. At. Spectrom.
- J. Antibiot.
- J. Catal.
- J. Chem. Educ.
- J. Chem. Eng. Data
- J. Chem. Inf. Model.
- J. Chem. Phys.
- J. Chem. Theory Comput.
- J. Chromatogr. A
- J. Chromatogr. B
- J. Clean. Prod.
- J. CO2 UTIL.
- J. Colloid Interface Sci.
- J. Comput. Chem.
- J. Cryst. Growth
- J. Dairy Sci.
- J. Electroanal. Chem.
- J. Electrochem. Soc.
- J. Environ. Manage.
- J. Eur. Ceram. Soc.
- J. Fluorine Chem.
- J. Food Drug Anal.
- J. Food Eng.
- J. Food Sci.
- J. Funct. Foods
- J. Hazard. Mater.
- J. Heterocycl. Chem.
- J. Hydrol.
- J. Ind. Eng. Chem.
- J. Inorg. Biochem.
- J. Magn. Magn. Mater.
- J. Mater. Chem. A
- J. Mater. Chem. B
- J. Mater. Chem. C
- J. Mater. Process. Tech.
- J. Mech. Behav. Biomed. Mater.
- J. Med. Chem.
- J. Membr. Sci.
- J. Mol. Catal. A Chem.
- J. Mol. Liq.
- J. Nat. Gas Sci. Eng.
- J. Nat. Prod.
- J. Nucl. Mater.
- J. Org. Chem.
- J. Photochem. Photobiol. C Photochem. Rev.
- J. Phys. Chem. A
- J. Phys. Chem. B
- J. Phys. Chem. C
- J. Phys. Chem. Lett.
- J. Polym. Sci. A Polym. Chem.
- J. Porphyr. Phthalocyanines
- J. Power Sources
- J. Solid State Chem.
- J. Taiwan Inst. Chem. E.
- Macromol. Rapid Commun.
- Mass Spectrom. Rev.
- Mater. Chem. Front.
- Mater. Des.
- Mater. Horiz.
- Mater. Lett.
- Mater. Sci. Eng. A
- Mater. Sci. Eng. R Rep.
- Mater. Today
- Meat Sci.
- Med. Chem. Commun.
- Microchem. J.
- Microchim. Acta
- Micropor. Mesopor. Mater.
- Mol. Biosyst.
- Mol. Cancer Ther.
- Mol. Catal.
- Mol. Nutr. Food Res.
- Mol. Pharmaceutics
- Mol. Syst. Des. Eng.
- Nano Energy
- Nano Lett.
- Nano Res.
- Nano Today
- Nano-Micro Lett.
- Nanomed. Nanotech. Biol. Med.
- Nanoscale Horiz.
- Nat. Catal.
- Nat. Chem.
- Nat. Chem. Biol.
- Nat. Commun.
- Nat. Energy
- Nat. Mater.
- Nat. Med.
- Nat. Methods
- Nat. Nanotech.
- Nat. Photon.
- Nat. Prod. Rep.
- Nat. Protoc.
- Nat. Rev. Chem.
- Nat. Rev. Drug. Disc.
- Nat. Rev. Mater.
- Natl. Sci. Rev.
- Neurochem. Int.
- New J. Chem.
- NPG Asia Mater.
- npj 2D Mater. Appl.
- npj Comput. Mater.
- npj Flex. Electron.
- npj Mater. Degrad.
- npj Sci. Food
- Pharmacol. Rev.
- Pharmacol. Therapeut.
- Photochem. Photobiol. Sci.
- Phys. Chem. Chem. Phys.
- Phys. Life Rev.
- PLOS ONE
- Polym. Chem.
- Polym. Degrad. Stabil.
- Polym. J.
- Polym. Rev.
- Powder Technol.
- Proc. Combust. Inst.
- Prog. Cryst. Growth Ch. Mater.
- Prog. Energy Combust. Sci.
- Prog. Mater. Sci.
- Prog. Photovoltaics
- Prog. Polym. Sci.
- Prog. Solid State Chem.
- Sci. Adv.
- Sci. Bull.
- Sci. Rep.
- Sci. Total Environ.
- Sci. Transl. Med.
- Scr. Mater.
- Sens Actuators B Chem.
- Sep. Purif. Technol.
- Small Methods
- Soft Matter
- Sol. Energy
- Sol. Energy Mater. Sol. Cells
- Solar PRL
- Spectrochim. Acta. A Mol. Biomol. Spectrosc.
- Surf. Sci. Rep.
- Sustainable Energy Fuels