The interaction of Toluidine blue with Sodium Alginate has been investigated by spectrophotometric method. The polymer induces metachromasy in the dye as evidenced from the considerable blue shift in the absorption maxima of the dye. The interaction constant and thermodynamic parameters of polymer-dye interaction have been determined. The effect of alcohols on the reversal of metachromasy has b...

The addition of a macromolecular crowding agent to a dilute solution of polymer exerts a compressive force that tends to reduce the size of the chain. We study here the effect of changing the size ratio between the random coil and the crowding agent. The compression occurs at lower crowding agent concentration, Φ when polymer molecular weight increases. The Flory exponent ν(Φ) decreases from ν(...

The diffusion of water in mixtures of water and poly(vinyl alcohol) (0-97%) has been investigated using atomistic molecular dynamics simulation. The dependence of the calculated diffusion coefficients on the polymer concentration follows the Mackie-Meares equation to a good approximation. It is found that the pattern of water diffusion undergoes a pronounced change with concentration and temper...

We present a neutron-scattering study of depletion interactions in a mixture of a hard-sphere-like colloid and a nonadsorbing polymer. By matching the scattering length density of the solvent with that of the polymer, we measured the partial structure factor Sc(Q) for the colloidal particles. It is found that the measured Sc(Q) for different colloid and polymer concentrations can be well descri...

If we could realize an autonomous polymer system driven under biological conditions by a tailor-made molecular design, human beings could create unprecedented biomimetic functions and materials such as heartbeats, autonomous peristaltic pumps, etc. In order to achieve this objective, we have investigated the molecular design of such a polymer system. As a result, we were the first to demonstrat...

Using a model colloidal system of alumina and polyacrylic acid (PAA), the kinetics of flocculation was investigated at low polymer concentrations and short durations (on the order of seconds). The polymer-induced flocculation processes obeyed Von Smoluchowski's bimolecular rate equation. Increases in the concentration of the polymer resulted in higher rate constants for the flocculation process...

The interaction between a flexible polymer in a good solvent and smaller associating solute molecules such as amphiphiles (surfactants) is considered theoretically. Attractive correlations, induced in the polymer because of the interaction, compete with intra-chain repulsion and eventually drive a joint self-assembly of the two species, accompanied by partial collapse of the chain. Results of t...

Porous hydrogels of poly(ethylene glycol) (PEG) have been shown to facilitate vascularized tissue formation. However, PEG hydrogels exhibit limited degradation under physiological conditions which hinders their ultimate applicability for tissue engineering therapies. Introduction of poly(L-lactic acid) (PLLA) chains into the PEG backbone results in copolymers that exhibit degradation via hydrol...