RIS Metropolis Monte Carlo studies of some aliphatic main chain and side group polyesters

Abstract

Structure related single chain properties of polyesters with isolated carboxyl groups have been studied to test the performance of the RIS Metropolis Monte Carlo (RMMC) method. The mean square end-to-end distances, radii of gyration, characteristic ratios and persistence lengths have been calculated for poly(methyl acrylate), poly(methyl metacrylate), poly(vinyl acetate) and for some aliphatic main chain polyesters having alkyl chains of various lengths between the carboxyl groups. The PCFF force field, modified by the authors in a recent study on some model molecules for the polyesters in question, has been used in the generation of chain conformations. The effect of the choice of run parameters (i.e. the cut-off limit for nonbonded interactions and chain length) on the results is discussed in more detail. The characteristic ratios calculated with the RMMC method using the PCFF force field with the refined torsion potentials agree well with the experimental values. The dependence of the calculated characteristic ratios on the tacticity of the chain in poly(methyl metacrylate) is found to follow experimental behavior.