Abstract By the example of highly concentrated water-in-oil emulsions, in which droplets of a supersaturated aqueous ammonium nitrate solution are dispersed in industrial oil, it has been shown that a thermodynamically stable state is possible due to the limited volume of dispersed phase particles.

Abstract— Enzymes play significant roles in both life and industry, and increasing enzymatic activity has been a long-term goal of the biochemical science. Recently, it has been reported that nanomaterials can enhance both the specificity and yield of polymerase chain reaction (PCR) though the mechanism of this enhancement remained unclear. By using gold nanoparticles (AuNPs) as model nanomaterials

Abstract An analytic solution for the two-layered model of pulsatile blood flow in stenotic arteries is discussed. The blood flow in narrow arteries is assumed to obey the two-fluid model: non-Newtonian viscoelastic as Jeffrey fluid in core region, and Newtonian as plasma fluid in peripheral region. The present study is aimed to develop an oscillatory viscoelastic model of blood flow and obtain the

Abstract The kinetics of adsorption of two polylysine samples with different molecular weights from aqueous solutions on the surface of fused quartz has been studied by the capillary electrokinetics method. It has been found that the adsorption of positively charged polylysine on the negatively charged quartz surface decreases the absolute value of the initial ζ potential; moreover, in the case of

Abstract It has been shown that, when passing from the Becker–Döring finite-difference equations to the differential kinetic equation for the function of aggregate distribution over aggregation numbers, the value of the error in the calculation of the times of fast relaxation in a micellar solution is primarily determined by the approximation used for the behavior of the aggregation work in the vicinity

Abstract Water may be involved in reverse micelle formation either in the form of a hydration shell or as a solubilisate. Both cases have been analyzed within the framework of a theory based on the mass action law and the definition of the critical micelle concentration (CMC) via the constant of this law. In the first case, it is supposed that a surfactant is primordially hydrated, and water is a priori

Abstract The goal of this work is the experimental verification of a recently formulated thermodynamic theory of the temperature dependence of sessile bubble contact angle [Rusanov, A.I., Colloid J., 2020, vol. 82, p. 303]. In particular, the possibilities of an increase in small contact angles and a decrease in large ones (larger than 90°) are tested. The experiments are carried out with a bubble

Abstract The influence of a magnetic field on the features of photoinduced thermocapillary deformation of the free surface of a magnetic fluid layer is considered for the first time. Deformation occurs as a result of local heating of the surface under the action of an incident laser beam and manifests itself as a curvature of the fluid surface profile. The laser beam reflected from the deformed surface

Abstract To date, it has been reliably shown by direct methods that a sessile droplet on a solid surface causes deformation of the substrate. For solids with rather low elasticity moduli, in particular, elastomers, this phenomenon becomes observable, and the deformation work reaches values sufficiently large to take it into account in the theory when necessary. Within the framework of the current theory

Abstract A boundary perturbation method is presented to investigate the modified micropolar Brinkman model. A slightly micro-corrugated cylindrical tube is filled with a porous medium in which a micropolar fluid flows through its pores. Stationary random model is used to mimic the surface roughness of the tube. The amplitude of the corrugations, which are perpendicular to the flow, is assumed to be

Abstract The review analyzes the general trends of the studies devoted to the encapsulation of various functional compounds (from drugs to corrosion inhibitors) in silica mesoporous container particles (MCPs). The main focus is on discussing new approaches to creating such structures. Primarily, they are approaches that allow one to combine the stages of the synthesis of MCPs and their loading with

Abstract The droplet coalescence theory, which implies the refinement and further development of the Frenkel approach, has, for the first time, been used for predicting the characteristic time of coalescence of nanodroplets. The coalescence times obtained for gold nanodroplets agree, in the order of magnitude, with the results of our molecular-dynamics experiments. In addition, the characteristic times

Abstract Surface properties of aqueous dispersions of bovine serum albumin complexes with silica nanoparticles have been studied using a set of methods that are sensitive to changes in the structure and composition of surface layers. In spite of the similar charges of the components, their interaction leads to changes in the surface properties of the dispersions; namely, the rates of variations in

Abstract The resistance model has been employed to derive an expression for the permeability of a composite membrane taking into account the viscous flow of a gas and the porous structure of a membrane support. Mathematical simulation has been used to show that, when the material of a selective layer does not penetrate into the pores of the skin layer of the support, the viscous flow of a gas in the

Abstract The basic factors influencing the quality of thin films prepared by the spin-coating technique from thermosetting stoichiometric epoxy-amine mixtures have been studied. It has been shown that films 2.5–3.0 nm thick are formed on silicon supports from a 0.025 wt % solution of the stoichiometric mixture of epoxy resin and amine in toluene. Multilayer polymer coatings with thickness up to 40

Abstract Polydopamine is formed via dopamine hydrochloride (DAH) polymerization in a slightly alkaline medium (pH 8.5) both in a solution bulk and at a liquid–gas interface. Atmospheric oxygen and oxygen dissolved in the bulk solution serves as an oxidizing agent. Compression isotherms of polydopamine films formed at the interface for different times at different initial DAH concentrations have been

Abstract Approaches have been proposed for determining the dispersity of a gold organosol with an AOT concentration of 0.25 M by examining the surface of an Au–AOT composite film by scanning electron microscopy (SEM) and atomic force microscopy (AFM) methods. The film has been obtained from a concentrated sol by the Doctor Blade method and subjected to thermolysis at 523 K for 2 h. The composite consists

AbstractThe mechanical characteristics of bacterial cellulose (one of the most promising cellulose-based nanomaterials) fundamentally depend on its moisture content. It has been found that the effect of aqueous solutions of alkali metal chlorides on its strength and deformation properties is determined by the mobility of water molecules in the near coordination spheres of cation hydration shells.

AbstractThe structure-related morphological characteristics and fractional composition of Al–2B composite powders obtained by mechanical alloying have been studied as depending on the physicochemical conditions of the process. Quantitative data on the morphology, microstructure, and particle size distribution functions of the composite powders have been obtained at different stages of their mechanical

AbstractThe main colloid-chemical properties have been determined for Ce0.5Zr0.5O2 hydrosols, the particles of which consist of a solid solution of cerium and zirconium dioxides. It has been shown that these hydrosols have aggregative stability close to that of ZrO2 hydrosols, although their particles contain 50 mol % cerium dioxide, which is less hydrophilic than zirconium dioxide. The sizes, densities

AbstractThe rheological properties of concentrated suspensions containing 55 and 60 vol % aluminum particles are studied. This concentration range corresponds to the transition from the viscoelastic to the elastoplastic behavior of the suspensions. Moreover, this range is most favorable for powder injection molding of metals and ceramics. The measurements are performed in a rheometer at different shear

AbstractDimensionally stable aerogels that retain their shapes and geometric sizes in solutions have been formed from cellulose subjected to an intense mechanical treatment in combination with freeze-thawing. This treatment has resulted in partial separation of numerous micro/nanosized fibrils that surround residual fibers. Their entanglement promotes an increase in the mechanical strength and stability

AbstractIn connection with the development of methods for the delivery of lipophilic drugs in a bioavailable form, we have employed an integrated approach to the investigation of the adsorption of an antihypertensive drug, felodipine, at interfaces that simulate the surfaces of different carriers. Isotherms have been plotted for felodipine adsorption from solutions in heptane (C = 2.13 × 10–5 − 4.26

AbstractIn addition to our previous work [1], a detailed analysis has been carried out for the angular dependences of all components of the pressure tensor in a wedge-shaped cavity of a solid with dispersion forces. It has been shown that the pressure tensor components satisfy the conditions of mechanical equilibrium as a function of the distance from the walls of the wedge-shaped cavity and the angular

AbstractA vacancy has been formed in a crystal lattice by removing an iodine anion from the crystallographic layer nearest to the surface on the basal face of the β-modification of silver iodide. The Monte Carlo method has been employed to study the molecular structure of condensed water phase nuclei growing in the field of the vacancy from a vapor at 260 K. The images and spatial correlation functions

AbstractTwo modifications of the mass action law are considered as applied to defining the critical micelle concentration (CMC) via constant K of the law. The first, traditional, modification defines the CMC as \({{K}^{{1/(1 - n)}}},\) where n is the aggregation number, and the second one—as \({{(Kn)}^{{1/(1 - n)}}}.\) In both cases, the formulation of the mass action law is extremely simplified due

AbstractThe deposition of aerosol particles in diffusion batteries composed of model screens oriented perpendicularly to a Stokes flow has been considered. The particle collection efficiencies have been calculated as depending on screens parameters and the Peclet diffusion number. It has been shown that, at large Peclet numbers, the particle penetration through dense screens is independent of the interscreen

AbstractThe electrosurface properties have been experimentally studied for different monodisperse fractions of hydrosol particles of detonation nanodiamond (DND) obtained by air annealing of particle agglomerates, their deagglomeration by sonication in demineralized water, and subsequent centrifugation of resulting hydrosols. The acid-base potentiometric titration and laser Doppler electrophoresis

AbstractThe laws and mechanisms of adsorption of Cu(II) ions by well characterized and oxidized N‑doped multi-walled carbon nanotubes (N-CNTs) are discussed. The samples were synthesized by catalytic chemical vapour deposition method using n-butylamine as a carbon source and their surface was functionalized by oxidation with mixture of concentrated H2SO4 and HNO3. The morphology, chemistry and charge

AbstractMolecular dynamics has been employed to study conformational rearrangements of polyampholytic polypeptides adsorbed on the surface of a metal nanoparticle, with the rearrangements being caused by changes in the direction of particle polarization at a frequency corresponding to microwave electric field. The time dependences of the dipole moments, as well the radial and angular density distributions

AbstractThe effect of the concentration and of the composition of mixtures of a traditional surfactant sodium dodecyl sulphate (SDS) and of linalool (LL), a volatile fragrance with surface-active properties, on the surface tension of their aqueous solutions has been studied. Surface tension was measured both under equilibrium and under dynamic conditions of the surface formation (in a time range of

AbstractThe dependence of liquid contact angle on the pressure in a gaseous mixture occurring in contact with the liquid has been considered on the basis of the general thermodynamic relations reported in the previous work for small although macroscopic bubbles and droplets. The cases of a sessile droplet brought in a direct contact with a gas occurring under a certain pressure and a sessile bubble

AbstractResults of studying the electric polarizability of colloidal graphite particles in an aqueous 1 : 1 electrolyte solution at frequencies of 100 Hz to 2.5 MHz have been presented. The polarizability anisotropy, surface conductivity, and electrokinetic potential of graphite particles have been investigated in aqueous KCl solutions with concentrations lower than 0.2 mmol/L. The dispersion of polarizability

AbstractSorption of histidine in the cationic and zwitterionic forms on a framework aluminosilicate, clinoptilolite, has been investigated. The contributions of the exchange and nonexchange mechanisms of sorption to the sorption capacity have been determined. It has been shown that monolayer histidine sorption on clinoptilolite by the ion-exchange mechanism proceeds due to the electrostatic interaction

AbstractThe peculiarities of the synthesis of silica-based mesoporous container particles with the use of sodium oleate as a templating agent have been discussed. Sodium oleate is an anionic surfactant and an efficient corrosion inhibitor. It has been shown that the container particles obtained as a result of combining the stages of their synthesis and loading contain a very large amount of the inhibitor

AbstractA review of the theoretical data accumulated for the last decade on the diffusion kinetics of the stage of homogeneous nucleation of liquid droplets and gas bubbles in multicomponent systems has been presented. In addition to the previously known results, the review contains new relations and discussions that represent the further development of own studies. Thermodynamic expressions that relate

AbstractA high-productivity method has been proposed for the synthesis of silver nanoparticles with sizes of 11.2 ± 0.3 nm in water-in-oil emulsions stabilized with sorbitan monooleate (Span 80). It has been shown that, in the course of the synthesis, initial reagents are transferred from emulsion droplets into Span 80 micelles. As a result, nanoparticles are formed due to the intermicellar exchange

AbstractThe structural characteristics (structural resistance coefficient, volume porosity, tortuosity coefficient, average pore radius, specific surface area) and specific electrical conductivity of high-silica micro- and macroporous glasses with different compositions (basic magnetite-free and magnetite-containing glasses) have been studied in solutions of sodium, lanthanum, and iron(III) chlorides

AbstractHydrogels have been prepared by mixing chitosan and pectin solutions, as well as solutions of their modified derivatives, in aqueous media at room temperature. The gels are obtained within a time period from several seconds to half an hour or more, depending on the process conditions. The hydrogels are formed due to both the covalent bonding between functional groups and the formation of interpolyelectrolyte

AbstractConvincing arguments have been presented testifying that that the surface tension of a small spherical droplet must decrease upon diminishing droplet radius in correspondence with a positive constant Tolman length. The solution of the Gibbs–Tolman–Koenig–Buff equation has been found in the most compact form. The surface tension of a small spherical droplet has been calculated within the framework

AbstractIn this work we present a mathematical model for the flow of two fluids (micropolar and Newtonian ) through concentric cylinders having porous space of different permeability. The Poiseuille flow of micropolar fluid takes place in core region while Newtonian fluid in the annular region of concentric cylinders respectively. An analytical expression of velocity, flow rate, micro rotational velocity

AbstractUniform silver nanoparticles with diameters smaller than 10 nm have been synthesized by the hydrothermal method on micro/nanofibrils of cellulose, which is used as a substrate, in a solution consisting of a water/ethylene glycol (reductant) mixture, a silver salt, poly(vinylpyrrolidone), and silver chloride used as a seed. Cellulose plays the role of an additional mild reductant, which prevents

AbstractIt has been shown that the adsorption of inorganic phosphates, the molecules of which contain one to three phosphorus atoms, on the surface of nanocrystalline titanium dioxide may be interpreted as the formation of complexes of two types, i.e., outer-sphere electrostatic and inner-sphere covalent complexes. The stability constants of the adsorption complexes of both types have been calculated

AbstractNumerous experimental data are available on contact angles. However, the majority of them concern sessile droplets, although bubbles are more interesting from the point of view of colloid science, because a sessile bubble is distinguished by the existence of an equilibrium thin liquid film at a gas–solid interface. This paper presents the totality of modern thermodynamic equations necessary

AbstractHydroxyapatite nanoparticles (NPs) have been synthesized by controlled precipitation in the presence of a surfactant, sodium dodecyl sulfate. The sizes, shapes, and structures of the NPs depend on the sequence of mixing the reagents . When the addition of sodium phosphate to a surfactant solution is followed by the addition of calcium nitrate, rodlike hydroxyapatite NPs are formed, the length

AbstractA magnetic fluid has been synthesized on the basis of magnetite particles stabilized with poly(dimethylsiloxane) (PDMS) having a molecular weight of 4670. PDMS-stabilized particles retain their mobility after the twofold dilution of this fluid with n-pentane and cooling to a temperature of –95°C. A concentrated sample of the magnetic fluid containing only particles with stabilizing shells has

AbstractFlow around a Reiner–Rivlin non-Newtonian liquid particle, which is surrounded with a Newtonian liquid shell and placed into a permeable medium, is studied. This formulation of the problem is typical for, e.g., studying the motion of an oil droplet surrounded with an aqueous medium (oil-in-water emulsion) in a porous collector under the action of an external pressure drop. An analogous problem

AbstractPalladium nanoparticles catalyze the reduction of Ag+ ions with hydrogen on their surface, thereby leading to the formation of bimetallic particles with the “core–shell” structure. The catalytic reaction of methylviologen reduction with hydrogen at ratio [Ag] : [Pd] > 1 is suppressed by silver atoms located on the surface of palladium nanoparticles. At [Ag] : [Pd] ≤ 1, the reduction takes place;

AbstractThe mechanism of montmorillonite modification with sodium metasilicate for inversing its ion-exchange characteristics has been studied. The blockage of the interlayer space in montmorillonite by amorphous silicon–oxygen clusters, which are formed as a result of sodium metasilicate hydrolysis, hinders the access of ions to the internal negatively charged surface of the mineral and increases

AbstractA methodological approach has been proposed for studying the effect of solvent nature on the adhesive properties of films of binary copolymers with different chain microstructures. The approach is based on a complex analysis of the thermodynamic work of adhesion in polymer–liquid model systems and the results of mechanical tests in combination with quantum-chemical calculations. The approach

AbstractGas transfer through a composite has been studied. The main parameters affecting the membrane permeability have been determined. It has been shown that, in the presence of a viscous flow of a gas through a porous support, its flow rate through the composite membrane depends on the direction of transfer. The intensity of this effect increases with an increase in the support resistance to the

AbstractA method has been proposed for calculating linear dynamic magnetization of a viscoelastic ferrocolloid in a constant magnetic field (displacement field). The magnetic phase of the colloid consists of Brownian ferromagnetic nanoparticles placed into a Jeffry’s fluid. Therefore, each particle, upon its rotation induced by an alternating (probe) field, dissipates energy via two friction “channels”

AbstractThe stability of spherical nanoclusters of methane and carbon dioxide hydrates in the environment of supercooled water has been studied by the molecular dynamics method under the isochoric and isobaric conditions. The process of system melting has been considered within a temperature range of 180–280 K and at pressures of 1, 50, and 100 atm (under isobaric conditions). It has been shown that

AbstractThe nonexchange sorption of diverse electrolytes by an MK-40 sulfonic cation-exchange membrane has been studied by conductometry without separating solution and membrane phases. The data of sorption experiments performed within the framework of the two-phase microheterogeneous model of an ion-exchange material have been used to find the Donnan constant for the MK-40 membrane in solutions of

AbstractStable silver nanoparticles have been obtained in reverse micelles of known and available nonionic surfactants, sorbitan monooleate (Span 80) and tetraethoxylated dodecanol and p-nonylphenol (Brij 30 and Tergitol NP-4, respectively), in n-decane. The obtained nanoparticles have been characterized using a number of physicochemical methods. The stability, hydrodynamic diameter, and electrokinetic

AbstractA comparative analysis has been performed for the structure of ring deposits resulting from the evaporation of droplets of aqueous dispersions of gold nanorods and composite nanoparticles with a gold core/organosilica shell structure based thereon. The nature of the particles has been shown to have a key effect on the character of their packing near a three-phase contact line. The study of

AbstractCross-linked cationic particles 150–300 nm in diameter have been synthesized via single-stage emulsifier-free copolymerization of methyl methacrylate and 2-aminoethyl methacrylate hydrochloride in the presence of cross-linking agents (ethylene glycol dimethacrylate and N,N'-methylenebisacrylamide). Factors that enable one to control the morphology and polydispersity of the resulting particles

AbstractMolecular dynamics has been employed to study rearrangements in the conformational structure of polyampholytic macrochains with different distributions of charged units in the electric field of a polarized metal nanoparticle. The angular and radial distributions have been calculated for the average densities of polypeptide atoms. The radial distributions of the average density of polypeptide

AbstractA method has been developed for the synthesis of calcium carbonate particles with the use of mesoporous silica particles as a template. Hydrosols of the synthesized CaCO3 particles are unstable with respect to aggregation at neutral pH values and coagulate to yield aggregates with submicron sizes. A procedure of electrostatic stabilization by adding an aqueous FeCl3 solution has been proposed

AbstractA model approach is developed, which enables one, using the concentration dependences of the diffusion permeability for individual layers, to estimate the density of a diffusion flux through a bilayer membrane, determine the concentration of a virtual solution at the interface between the membrane layers, and find the thickness of each layer that has constant diffusion characteristics. The