The interplay between the chain stiffness and the local structure of fluorine containing polymers in the melt

Abstract

A detailed study of the relationship between chain stiffness and the local structural arrangements in a series of molten Fluorine containing polymers is presented. Four polymers of the form -(CF2CFX)n- are considered with X = F, Cl, Br and D together with poly(ethylene), -(CH2CH2)n-. By comparing the experimental structure factor with those obtained from atomistic models quantitative structural parameters are obtained which describe the intrachain structure. The introduction of differing substituents into these Fluorine containing polymers has a marked impact on the nature of the local chain conformation. Using these models of the intrachain structure as a starting point, we have utilised reverse Monte Carlo techniques to derive information on the spatial and orientational correlations between these chains segments in the melt. Somewhat surprisingly the rather anisotropic chains segments of -(CF2CF2)n- show less orientational correlations between near neighbour segments than the rather flexible -(CH2CH2)n- system.