Molten globule state in homopolymers: A Monte Carlo study

Simple models of polymer chains were based on a simple cubic lattice. The m odel chains were star-branched with f = 3 and f = 6 branches. The attractiv e potential between polymer segments was introduced to study the properties of polymer chains in the different temperature regimes. The computer simul ations were carried out by means of the dynamic Monte Carlo method. It was found that contrary to recent real experiments, the ratio of the radius of gyration to the hydrodynamic radius did not exhibit a maximum near the coil -globule transition but decreased monotonically with the temperature. The d istribution of polymer-polymer contacts and their lifetimes were also studi ed. It appeared that in homopolymer chains the lifetimes of these contacts were very short. At low temperatures contacts were distributed over the ent ire chain and at high temperatures only contacts that were close to the cha in survived longer times.