Conformations of attractive, repulsive, and amphiphilic polymer chains in a simle supercritical solvent: Molecular simulation study

摘要

Using the configurational-bias Monte Carlo method combined with the parallel tempering technique, solvent driven changes in polymer conformations in a supercritical solvent are systematically investigated using simple molecular models. The solvent is modelled as a square-well fluid, and the polymer is made up of a flexible chain of tangentially touching hard spheres and/or square-well spheres. The mean square end-to-end distance and radius of gyration are computed for various ratios of square-well and hard-sphere segments and a range of thermodynamic conditions. The simulation results show that conformation behavior of amphiphilic chins is rather complex and it is not a simple combination of the conformation behavior of the attractive and repulsive chains. The main finding is that the conformations of amphiphilic chains is determined primarily by attractive intermolecular interactions between the polymer segments and molecules of the solvent.