Simulation study of a polymer in dilute solution

We employ Molecular Dynamics simulations to study the phase behavior and equilibrium dynamics of a fully flexible Lennard-Jones chain immersed in a Lennard-Jones solvent at high solvent densities. The hydrophobicity of the model polymer is adjusted by varying the attractive component of either the monomer-monomer or monomer-solvent potential. >From an analysis of the static structure factor of the chain, we determine the coil-globule transition point. We study the effects of solvent density, chain length and solvent finite-size effects on the coil-globule transition, and quantify the degree to which depletion forces contribute to stabilizing the globule state. In addition, we study the dynamics of the polymer chain under good solvent conditions by analyzing the Rouse mode correlation functions within the context of a refined version of the Zimm theory of polymer dynamics. We compare the effects of chain length, solvent viscosity and system size on the correlation times measured in the simulation with those predicted by the theory. Discrepancies between simulation and theoretical results are accounted for by an analysis of various approximations employed in the theory for the model system studied in the simulation.