Crystallization of conjugated polymers*

The final semicrystalline morphology of a polymer strongly depends on the processing conditions under which crystallization occurs. Even small variations in the degree of crystallinity, size/orientation of crystallites, and connectivity between crystalline aggregates can lead to significant changes in final properties. For conjugated polymers, the basic interplay between molecular structure, processing parameters and structure development remains particularly elusive because, typically, the crystallization process occurs under ill-defined flow and thermal conditions while a solvent evaporates relatively quickly. Here, we explore the crystallization behavior of poly-3-hexylthiophene of various molecular weights under well-defined conditions. The results suggest that memory and self-nucleation can play an important role in the way crystallization proceeds.