Hydrophilic poly(vinylidene fluoride) (PVDF) membrane by in situpolymerisation of 2-hydroxyethyl methacrylate (HEMA) and micro-phase separation

Abstract

A method of obtaining a hydrophilic and antifouling poly(vinylidene fluoride) (PVDF) membrane is developed via in situ polymerisation of 2-hydroxyethyl methacrylate (HEMA) in PVDF solution and subsequent micro-phase separation. The immobilization of PHEMA in a PVDF membrane was verified by Fourier Transform Infrared Spectroscopy (FTIR) and ¹H Nuclear Magnetic Resonance Spectroscopy (¹H-NMR). X-ray Photoelectron Spectroscopy (XPS) studies further unveiled the enrichment of PHEMA on the PVDF membrane surfaces. Scanning Electron Microscopy (SEM) and Atomic Force Microscopy (AFM) images revealed that the modified membrane had a fibrous-like microstructure in the cross section and a porous top surface. Water contact angle measurement suggested that the modified membrane formed by in situ polymerisation and micro-phase separation possessed higher hydrophilicity than the control membrane formed by blending PVDF and pre-polymerised PHEMA. The protein fouling of the modified membrane was considerably alleviated and the dried membrane showed spontaneous wettability and excellent permeability. Based on Wide-Angle X-ray Diffraction (WAXD) and the above results, a possible membrane formation mechanism for the in situ polymerisation and subsequent micro-phase separation was proposed.