Rod-like crystal growth of dioctyl substituted polyfluorene from nematic and isotropic states

The growth behavior of the rod-like α-form crystals from both the liquid crystal and the isotropic melt state was studied in situ and in real time using a hot-stage atomic force microscopy. The growth rate and direction of the poly(9,9-dioctylfluorene) (PFO) α-form crystals are greatly affected by the orientation of the polymer chains in the liquid crystal matrix. The pre-existence of chain alignment in the liquid crystal matrix serves as a precursor for crystallization, which greatly reduces the growth energy barrier and promotes the overall growth rate of PFO α-form crystals. Our results provide some valuable information for understanding the relationship between morphology and photoexcited emission behaviors.