Improving the order of crystalline regions of poly(3-hexylthiophene) by crystallization from the self-nucleation domains

Abstract

To obtain well-defined crystalline structures starting from an isotropic melt state, we crystallized poly(3-hexlylthiophene) isothermally at high temperatures, using various multi-step thermal protocols and profiting from a self-nucleation process. We explored the possible impact of self-nuclei from the melt memory domain and of remaining crystalline seeds from the self-seeding domain on isothermal crystallization at high temperatures. Depending on the thermal protocol, self-seeding allowed to obtain crystals grown from nuclei formed at the isothermal crystallization temperature and from crystalline seeds remaining after annealing at the self-nucleation temperature. Isothermal annealing of samples crystallized by rapid cooling from the isotropic melt allowed to significantly improve their crystallinity but to a lesser extent enhanced the crystalline quality, characterized by the value of the melting temperature.