THE CRYSTALLOGRAPHY OF POLYMER FOLDS. ITS IMPACT ON SPHERULITE MORPHOLOGY AND STRUCTURE

摘要

@@Introduction The structure and morphology of crystalline polymers involves different length scales. They range from sub-nanometers up to micrometers or even millimeters and deal with chain conformation, unit-cell, chain-folded lamellae and spherulites. Elucidation of these various levels of organization relies heavily on specific and wellestablished investigation techniques: X-ray fiber analysis to determine the chain conformation and crystallography, optical and electron microscopy to analyze larger scale features. The most elusive part of this analysis remains the correlation between spherulite structure and the smaller scale structural features. As an illustration, several research groups have attempted to correlate the sense, right or left, of lamellar twist in spherulites (giving rise to concentric bands in spherulites examined under polarized light) with the molecular chirality, R or S, in chiral polymers and biopolymers. These attempts have not been successful: no meaningful correlation