Социально-экономическое развитие г. Юрги в рамках ТОСЭР

В статье представлен анализ положительных и отрицательных сторон территории опережающего развития на примере города Юрги Кемеровской области. Ознакомление международной и российской историю становления стратегии ТОСЭР

Steric Repulsion by Adsorbed Polymer Layers Studied with Total Internal Reflection Microscopy

Total internal reflection microscopy (TIRM) was applied to measure the interaction potential between charge-stabilized polystyrene latex spheres and a glass wall in dependence on the concentration of additional poly(ethylene oxide). The influence of the polymer can be described by steric repulsion between polymer layers, which are physically adsorbed onto the surfaces of the polystyrene sphere and the glass wall. The expected attractive contribution to the potential due to polymer depletion was not observed. An increase of the polymer bulk concentration is shown to strengthen the steric repulsion. At the highest polymer concentrations studied, it is possible to accurately describe the experimental data for the steric contribution to the total interaction potential with the Alexander-de Gennes model for brush repulsion

Direct measurement of polymer-induced forces

Colloid-polymer mixtures are found in dispersions that are an important part of people's everyday lives. The dynamics and phase stability of colloid-polymer mixtures depend on the interactions that are present in these systems. Therefore, knowledge of interactions is of basic interest. Depending on their adsorption affinity polymers added to the colloidal suspension can cause steric stabilization or flocculation due to depletion or adsorption (bridging). This paper reviews theoretical and experimental work performed on polymer-induced interactions in colloidal suspensions. Theoretically, polymers have mainly been treated as ideal flexible chains or even generalized as non-interacting (phantom) spheres. Many relevant experiments, however, have been performed with polymer chains, which are polydisperse and/or charged and/or self-interacting. These cases are challenging for theoreticians: a limited amount of work performed on these systems is also discussed here. We particularly concentrate in this review on the direct experimental measurement of polymer-induced interactions. A brief description of techniques which enable these measurements is given and their strengths and weaknesses are discussed

Interaction potential and near wall dynamics of spherical colloids in suspensions of rod-like fd-virus

Averaged diffusivities of spherical colloids in solutions of rod-like particles, i.e. fd-virus, were measured with EWDLS and TIRM. While the experimentally observed near wall dynamics of the spheres in the absence of fd are well described by standard hydrodynamic theories, there are significant deviations at finite fd concentrations. Both experimental methods yield data which are significantly smaller than the theoretical predictions

Interactions and two-phase coexistence in nonionic micellar solutions as determined by static light scattering

We suggest semi-phenomenological approaches for the pair interaction potential in aqueous C(m)E(n) solutions. These expressions are non-linear least squares fitted to static light scattering data from solutions of C(m)E4 and C(m)E8 surfactants in the long wavelength limit. From the resulting interaction parameters we calculate the location of the liquid/liquid two phase coexistence curves, which are in very good agreement with experimental data reported by others

Depletion Interaction Mediated by a Polydisperse Polymer Studied with Total Internal Reflection Microscopy

Total internal reflection microscopy (TIRM) was applied to measure depletion forces between a charged colloidal sphere and a charged solid wall induced by dextran, a nonionic nonadsorbing polydisperse polysaccharide. The polymer size polydispersity is shown to greatly influence the depletion potential. Using the theory for the depletion interaction due to ideal polydisperse polymer chains, we could accurately describe the experimental data with a single adjustable parameter

Lyotropic Smectic B Phase Formed in Suspensions of Charged Colloidal Platelets

Here, we present the first observation of a smectic B (Sm(B)) phase in a system of charged colloidal gibbsite platelets suspended in dimethyl sulfoxide (DMSO). The use of DMSO, a polar aprotic solvent, leads to a long range of the electrostatic Coulomb repulsion between platelets. We believe this to be responsible for the formation of the layered liquid crystalline phase consisting of hexagonally ordered particles, that is, the Sm(B) phase. We support our finding by high-resolution X-ray scattering experiments, which additionally indicate a high degree of ordering in the Sm(B) phase