The interactions between spherical colloids covered with end-grafted polymers (brushes) immersed in a polymer melt are studied theoretically. We show that attractive enthalpic interactions between the two polymer species, characterized by a negative Flory parameter (chi<0), can stabilize the colloidal dispersion. The stabilizing mechanism is a result of a structural change from a dry brush, whe...

The swelling of polyelectrolyte hydrogels has been often explained using simple models derived from the Flory–Rehner model. While these qualitatively predict experimentally observed trends, they also introduce strong approximations and neglect some important contributions. Consequently, sometimes incorrectly ascribe trends to contributions which are minor importance under given conditions. In t...

The scaling properties of self-avoiding polymerized 2-dimensional membranes are studied via renormalization group methods based on a multilocal operator product expansion. The renormalization group functions are calculated to second order. This yields the scaling exponent ν to order ε2. Our extrapolations for ν agree with the Gaussian variational estimate for large space dimension d and are clo...

The Flory-Reimer t heory for isotropic swelling of rubber crosslinked in t he dry state is extended to an anisotropic system crosslinked in t he dry, oriented state . The new parameters introduced into t he equation can be readily determined from dimensional changes of the fiber in a s ui table solvent using a photomicrographic te::hnique. Unlike other method3, s uch as the cathetometric and we...

A modification of the extended UNIQUAC model is proposed for the description of the non-ideality of protein solutions. Here, the Staverman–Guggenheim combinatorial contribution used in extended UNIQUAC model is replaced by the Flory–Huggins term to take into account the size differences between the protein and solvent. This new model allows an excellent description of the activity coefficients ...

The scaling properties of DNA knots of different complexities were studied by atomic force microscope. Following two different protocols DNA knots are adsorbed onto a mica surface in regimes of (i) strong binding, that induces a kinetic trapping of the three-dimensional (3D) configuration, and of (ii) weak binding, that permits (partial) relaxation on the surface. In (i) the radius of gyration ...

Here, we present a new method to model lateral phase separation in mixed polymer brushes physisorbed to a planar surface with mobile grafting points. The model is based on a local mean field theory that combines a Flory-Huggins approximation for interaction enthalpies with an Alexander-de Gennes brush entropy contribution. Using Monte Carlo sampling, the application of these two interactions to...

Some thermodynamic quantities were obtained for the interactions of poly [2-(3-mesityl-3-methylcyclobutyl)2-hydroxyethyl methacrylate] with alcohols, ketones, acetates, aromatics and alkanes by inverse gas chromatography in the temperature range 160-200◦C. The specific retention volumes, V ◦ g , weight fraction activity coefficients of solute probes at infinite dilution, Ω1 , Flory-Huggins ther...

The sorption of carbon dioxide in poly(lactic acid) (PLA) was studied by quartz crystal microbalance at high pressures. To address the effect of the D isomer present in the polymer on the gas sorption, measurements were performed in PLA with two different L:D contents, 80:20 and 98:2. New data for the solubility of carbon dioxide in PLA 80:20 and PLA 98:2 over a temperature range from 303.2 to ...