A Novel Method of Combining in Situ Polymerisation and Non–solvent Assisted Thermally Induced Micro–phase Separation to Improve Membrane Hydrophilicity

AbstractA method of obtaining hydrophilic and antifouling poly(vinylidene fluoride) (PVDF) membrane is developed via in situ polymerisation of 2–hydroxyethl methacrylate (HEMA) in PVDF solution and subsequent micro–phase separation. The immobilization of PHEMA in PVDF membrane was verified by Fourier Transform Infrared Spectroscopy (FTIR) and Hydrogen–1 Nuclear Magnetic Resonance Spectroscopy (1H–NMR). X–ray Photoelectron Spectroscopy (XPS) studies further unveiled the enrichment of PHEMA on 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 by in situ polymerisation and micro–phase separation possessed higher hydrophilicity than the control membrane 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 results above, a possible membrane formation mechanism for the in situ polymerisation and subsequent micro–phase separation was proposed