Computer Simulation Studies of Polymer Adsorption and Aggregation – From Flexible to Stiff

Abstract

This mini-review gives a brief overview of our recent Monte Carlo computer simulations of polymer adsorption and aggregation based on coarse-grained continuum models of theta polymers focusing on excluded volume, short-range attraction and bending stiffness. The simulations are performed in generalized ensembles (multicanonical and parallel tempering) and analyzed with canonical and microcanonical methods. For flexible polymers, besides plane adsorbing surfaces also the curved inner wall of a spherical cage has been considered. For semiflexible polymers, the dependence on bending stiffness is quite intricate and was recently found to lead to phases with stable knots of unique characteristics. For the special case of P3HT chains interacting with a gold surface, we have employed a chemically realistic coarse-grained model and compared the simulation results with scanning tunneling microscopy (STM) experiments under ultra-high vacuum conditions. The paper concludes with recent results on the aggregation process of semiflexible polymers. Our data shows that the bending stiffness plays a key role as to whether the polymer system forms amorphous aggregates or twisted bundle-like motifs.