Simulation studies of polymeric and colloidal systems

Abstract

In this thesis we investigated two different problems using computer simulations. First we employed Monte Carlo simulations for the study of the conformations of polymer chains in bulk and close to surfaces near the ‘coil-to-globule’ transition as a function of solvent quality and surface energy. We provided a satisfactory insight into the peculiarities of the ‘coil-to-globule’ transition and the effect of the presence of an attractive surface to it. Our results are in close agreement with theoretical predictions in bulk, whereas, they supply useful information on the competition between chain adsorption and chain collapse. The second problem was the investigation of the temperature induced changes in the colloidal superstructure and star-polymer dynamics in suspensions, under marginal solvent conditions, by means of Molecular Dynamics simulations. Star polymers were modeled as ‘soft-spheres’, whose size increased with temperature, interacting via a theoretically developed potential of mean field. Our results show a transition towards a ‘glassy’ state at a temperature very close to the one reported experimentally. Furthermore, our findings illustrate the road to vitrification for these soft colloidal suspensions.