Polymer Crystals and Crystallization: A Rediscovered and Challenging Research Field

Polymer crystal and polymer crystallization is a field that historically represents a significant development of polymer physics researches. It expands the research activities from thermodynamic equilibrium behaviors in polymer dilute solution to non-equilibrium thermodynamic properties in polymer semicrystalline solids. Analyzing and understanding the structure and morphology of crystalline polymers, polymer nucleation processes and growth models have been and remain to be major challenges. Some of the issues have resisted analyses for decades. A very large number of contributions in polymer crystals and polymer crystallization has helped to build a solid body of knowledge that must cover length scales ranging from sub-molecular units to morphology and correlates them with bulk properties. In this talk, a few specifically critical issues are paid attentions such as initial stage of primary nucleation and growth model of surface nucleation; the enthalpic and entropic origins of polymer nucleation barriers; polymer crystallization under confined environments; the correlation between crystal structure and morphology; the role of metastable states in polymer crystals and pathways of polymer crystallization; and relationships among the multiple phase transformations. Emphasis is put on structures and morphologies as formed spontaneously. Possible extension of the research area to connected fields is illustrated with a development on supramolecular crystals.