Nanophase morphology and crystallization in poly(vinylidene fluoride)/polydimethylsiloxane-block-poly(methyl methacrylate) blends

A polydimethylsiloxane-block-poly(methyl methacrylate) (PDMS-b-PMMA) diblock copolymer was synthesized by the atom transfer radical polymerization method and blended with a high-molecular-weight poly(vinylidene fluoride) (PVDF). In this A-b-B/C type of diblock copolymer/homopolymer system, semi-crystallizable PVDF (C) and PMMA (B) block are miscible due to favorable intermolecular interactions. However, the A block (PDMS) is immiscible with PVDF and therefore generates nanostructured morphology via self-assembly. Crystallization study reveals that both alpha and gamma crystalline phases of PVDF are present in the blends with up to 30 wt% of PDMS-b-PMMA block copolymer. Adding 10 wt% of PVDF to PDMS-b-PMMA diblock copolymer leads to worm-like micelle morphology of PDMS of 10 nm in diameter and tens of nanometers in length. Moreover, morphological results show that PDMS nanostructures are localized in the inter-fibrillar region of PVDF with the addition of up to 20 wt% of the block copolymer. Increase of PVDF long period by 45% and decrease of degree of crystallization by 34% confirm the localization of PDMS in the PVDF inter-fibrillar region. (c) 2018 Society of Chemical Industry