Monte Carlo Simulation of Many-Chain Star Polymer Solutions

Abstract

Many-chain systems of star polymer molecules in a good solvent have been investigated using a dynamic Monte Carlo algorithm on a simple cubic lattice. Several bead−jump moves are proposed for the central part of stars with three and four arms, in addition to the usual combination of bends, crankshafts, and terminal moves also employed for linear chains. Static properties such as the chain size, or the mean square radius of gyration, are calculated. It is shown that the ratio of the star size to that of a linear chain with the same number of units does not change with concentration. The collective scattering functions are also obtained for different concentrations, and the interchain structure factors obtained from these functions are compared with those corresponding to linear chains. The dynamics generated from the Monte Carlo trajectories yields Rouse modes which exhibit the expected dependencies on the mode number and chain length. Finally, the elastic and rotational relaxation modes of individual chains are shown to obey dependencies on the arm length and the number of arms that are compatible with the predictions of scaling theory.