Polymorphism and crystallization in poly(vinylidene fluoride)/ poly(ϵ-caprolactone)–block–poly(dimethylsiloxane)–block–poly(ϵ-caprolactone) blends

The miscibility, crystallization kinetics and crystalline morphology of a new system of poly(vinylidene fluoride)/poly(ϵ-caprolactone)-block-poly(dimethylsiloxane)-block-poly(ϵ-caprolactone) (PVDF/PCL-b-PDMS-b-PCL) triblock copolymer were investigated by a variety of techniques. The miscibility and phase behaviour of PVDF/PCL-b-PDMS-b-PCL were studied by determination of the melting point temperature, crystallization kinetics and Fourier transform infrared (FTIR) mapping. Chemical imaging was used as a new technique to characterize the interaction of polymer blends in crystalline morphology. The results demonstrate the existence of characteristic peaks of both PVDF and PCL in the chosen crystalline area. The crystalline structures of PVDF were affected by the PCL-b-PDMS-b-PCL triblock copolymer and facilitate the formation of the β polymorph which was illustrated by FTIR analysis. The β crystal phase fraction increases significantly on increasing the composition of the PCL-b-PDMS-b-PCL triblock copolymer. In addition, confined crystallization of PCL within PVDF inter-lamellar and/or inter-fibrillar regions was confirmed through polarizing optical microscopy, wide-angle X-ray diffraction and small-angle X-ray scattering analysis. © 2019 Society of Chemical Industry.