Simulations and experiments of self-associating telechelic polymer solutions

Abstract

A Brownian dynamics computer simulation study of a highly coarse-grained model oftelechelic associating polymers has been carried out. In a critical concentration range themodel produces the so-called ‘loops-to-bridges’ transition, thought to exist in theexperimental systems, in which the two hydrophobic groups are in different micelles,thereby forming a highly interconnected, ultimately percolating, network. The fraction ofbridged polymers produced by the model correlates well with the experimental viscosity atcorresponding concentrations. The distribution of micelle sizes compares favorably with thepredictions of the Meng–Russell free energy theory. The mean cluster size scales well withvolume occupancy according to a simple mean-field theory. The stress relaxation function isa stretched exponential at short times and not too high concentrations but develops alonger time plateau in the percolation region, both in agreement with experiment. Newexperimental data for the concentration dependence of the self-diffusion coefficient,viscosity, elastic modulus and relaxation time of telechelic associative polymers arepresented, which show broad qualitative agreement with the simulation data.