Study of structure formation during phase transitions in poly-p-phenyleneterephthalamide solutions

Structure Formation Phenomena During Phase Inversion. II. Semiflexible Polymers and Liquid Crystallinity

“…In the absence of any orientation, both a flexible polymer and a stiff polymer can form spherulites [34,35]. In the presence of orientation (with the minimum necessary strength and application time of an externally imposed orientational field being different for each case), both stiff polymers [34,35] and the highly flexible polyethylene can develop fibrillar morphology; the comparison can also be extended to include shish-kebab and row nucleation type of morphologies [34][35][36][37][38]. The main difference between the flexible and lyotropic behavior, at least at size scales of a few hundred angstrom or higher, pertains to the magnitude of the orienting field necessary to create a long-range axial orientation and the lifetime of that orientation in case the orienting field is turned off while the viscosity of the solidifying system is finite.…”

“…The comparison applies to the melt, reversible gel, and solution starting states for flexible polymers and to reversible gel and solution starting states for lyotropic polymers. In the absence of any orientation, both a flexible polymer and a stiff polymer can form spherulites [34,35]. In the presence of orientation (with the minimum necessary strength and application time of an externally imposed orientational field being different for each case), both stiff polymers [34,35] and the highly flexible polyethylene can develop fibrillar morphology; the comparison can also be extended to include shish-kebab and row nucleation type of morphologies [34][35][36][37][38].…”