Conformational properties of the bisphenol-A polycarbonate using the RMMC method

Abstract

The conformational properties of the bisphenol-A polycarbonate (PC) were studied using the rotational-isomeric-state metropolis Monte Carlo (RMMC) simulations adopting a polymer consistent forcefield (pcff). The conformations of a single PC chain were generated at theta condition in a wide range of molar mass. When the maximum bond number for non-bonded interactions is set to 5, the conformation corresponds to the unperturbed state. The probability that the dihedral bond pairs of diphenyl propane (DPP) groups exist at two minima of energy where the bond angles are (50.5, 50.5) and (−49.5, 129.5) is 3.4×10−4 at 300K. The probability of the trans–trans form of diphenyl carbonate (DPC) groups is 6.3×10−4 at 300K, and is reduced to 2.1×10−4 as temperature increases to 600K. The limiting unperturbed dimension in terms of mean-square end-to-end distance over molar mass (〈r2〉/M) is 1.01Å2mol/g. From intrinsic viscosity calculated with the radius of gyration (S), it was found that the gyration or the conformation of the PC chain at 300K is closer to that of dilute solutions in chloroform at 293K or in p-dioxane at 303K than in tetrahydrofuran (THF) solution at 297K. In future studies, the conformation obtained from the RMMC method here will be used as an initial structure to perform the molecular dynamics simulation in order to investigate interfacial properties of the PC bulk.