Simulations and experiments of self-associating telechelic polymer solutions

Abstract

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