Diversification of spherulite patterns in poly(ethylene succinate) crystallized with strongly interacting poly(4-vinyl phenol)

Poly(ethylene succinate) (PESu) blend with amorphous poly(vinyl phenol) (PVPh) in thin films were investigated on the crystalline spherulites patterns and crystalline lamellar arrangements by using polarized optical microscopic (POM) and atomic-force microscopy (AFM). A total of nine different types of crystalline morphology were identified in the PESu/PVPh blend with amorphous contents from 10 to 35 wt.% and T-c = 40-70 degrees C in ultra-thin film thickness. Multiple types of PESu crystalline morphology at the same crystallization temperature (Tc) are never seen in neat PESu, but only occur in PESu/PVPh blend with amorphous PVPh higher than 20 wt.%. Crystalline morphology diagrams are summarized to display various spherulite types in the PESu/PVPh blend confined in thin films as a function of crystallization temperature and blend composition. Crystallization temperature, thickness/space confinement, and presence of interacting amorphous PVPh are the main factors for multiple types of spherulites in the blends, partly due to strong interactions via hydrogen bonding between PESu and PVPh and likely extra nucleation capacity from the diffusion interfaces.