Enhanced physical, mechanical and protein adsorption properties of PVDF composite films prepared via thermally-induced phase separation (TIPS): Effect of SiO2@PDA nanoparticles

Abstract

In this work, SiO2@PDA nanoparticles obtained by in-situ coating polydopamine (PDA) on the surface of spherical SiO2 nanoparticles were adopted to prepare the polyvinylidene fluoride (PVDF) composite films via thermally-induced phase separation (TIPS) method with diphenyl carbonate (DPC) as the diluent. PDA was proved to cover evenly on the surface of SiO2 nanoparticles, which was favorable to the dispersion of hydrophilic nanoparticles in the matrix. Effect of the presence of SiO2@PDA nanoparticles on crystallization behavior, thermal stability, mechanical properties and hydrophilicity of the composite films was intensively investigated. Heterogeneous nucleating effect on the crystallization of PVDF coupled with elevated crystallinity was found upon the incorporation of SiO2@PDA without altering the crystal form of PVDF. The rigidity, tensile strength as well as thermal stability of the composite films containing SiO2@PDA were significantly improved in comparison to both neat film and those containing unmodified nanoparticles. In addition, the hydrophilicity of PVDF composite films’ surface was remarkably enhanced with an increasing SiO2@PDA content, which helped to reduce the protein adsorption of the composite films considerably. The present study would supply an insight into the fabrication of PVDF composite films with desirable performance and capabilities.