Structure and nanomechanics of linear dendronised polymers: a molecular simulation study

Abstract

We use Monte Carlo algorithms to simulate, on the atomistic scale, the structure and rigidity of model linear dendronised polymers (LDPs) consisting of a poly(para-phenylene) backbone with laterally substituted Fréchet type dendritic units. A coarse-grained representation of united atoms interacting via steric repulsions is employed for the study of the equilibrium structure of single LDPs as a function of dendron generation, g. Backbone conformation averages and dendron mass distributions are calculated for g = 0 to 5 and are used to elucidate the mechanism of stiffening of the LDP with increasing g. Congestion-induced stiffening, reflecting on the response of the backbone to linear extension as well as to bend and torsion deformations, is clearly detected for g = 4 and is dramatically intensified at g = 5 where, in addition, strongly bent and twisted structures develop along the backbone contour and reduce appreciably the equilibrium elongation of the LDP.