An In situ Study on the Orderly Crystal Growth of Pluronic F127 Block Copolymer Blended with and without Ionic Liquid during Isothermal Crystallization

Abstract

Isothermal crystallization behavior of Pluronic F127 blended with and without an ionic liquid (IL) was investigated by in situ polarized optical microscopy (POM) and Fourier transform infrared spectroscopy (FTIR). For the pure F127, the POM and FTIR results showed that the spherulite size and crystallinity of F127 increased with the melting temperature increasing to 60, 80, and 135°C. This could be explained by the flexibility of the polymer chain at high melting temperatures. For the F127 blended with IL, the POM results showed that the morphology of F127 evolved from spherulite to dendritic segregation and fibrous crystal with the increasing IL content. FTIR results indicated that hydrogen bonds were formed between F127 and IL, and the intensity of the hydrogen bonds became strengthened gradually with increasing IL content. The effect of hydrogen bonds on the morphology evolution of F127/IL is discussed.