Monte Carlo studies of the conformational statistics of polymers. Polyethylene

Abstract

The conformational distribution of unperturbed polyethylene (PE) has been studied utilizing the Monte Carlo approach. The results are in excellent agreement with experiments on the average dimensions of PE chains, as well as with the molecular scattering function obtained in mixtures of deuterated and hydrogenous PE at 400 K. Maps of the free energy as a function of two consecutive torsional angles confirm that an approximate description of the conformational distribution of PE can be given in terms of three rotational isomeric (RIS) states. The location of the states and the corresponding energy and entropy parameters, which can be separately evaluated from the Monte Carlo results, are compared with literature results obtained by internal energy calculations for butane and pentane.