Angular correlations in linear copolymers from the compositional dependence of their dipole moments. I. Random copolymerization

Abstract

A theory is developed, without recourse to a detailed model, for evaluating certain linear combinations of the average cosines of the angles between dipole moments of pairs of structural units that are closely spaced along the chain contour. Measurements of the compositional dependence of the effective dipole moment per structural unit together with a knowledge of the compositional dependence of the probabilities for various types of sequences of structural units provide the required information. The theory offers a possibility for testing the validity of certain restrictive assumptions that are implicit in earlier treatments of the problem. Additionally, the theory provides a basis for determining unequivocally from experimental measurements whether angular correlations exist among the structural units that contribute to the orientational part of the polarization and whether the angular correlation parameters, if they exist, depend on the types of structural units involved.