Preparation of Super-Hydrophobic Polyethersulphone Membrane by Sol-Gel Method

Abstract

Super-hydrophobic membrane has received extensive attention from basic theories and practical applications. The properties of the super-hydrophobicity of membrane are strongly dependent on the prepared method, which is attracting increasing concerns worldwide. The properties of super-hydrophobic membrane are dominated by many factors including the chemical composition and the morphology of the surface. In this work, a simple method to fabricate super-hydrophobic membrane with weak hydrophilic polyethersulphone (PES) via a sol-gel process is reported. The weak hydrophilic PES membrane was used as a membrane-based, which was dipped into precursor Sol firstly. After heat treatment, the membrane was dipped into the fluoroalkylsilane solution and then dried by again a heat treatment. The super-hydrophobic and porous PES membrane was characterized by Fourier-Transform Infrared Spectrometers (FTIR), contact angle goniometer, atomic force microscope (AFM). The results showed that the contact angle of super-hydrophobic membrane was up to 154°treated by precursor sol for 20min and fluorinated for 20h. The hydrophobic functional groups on the membrane surface were fluorinated groups (-CF3, -CF2, and -CF) and -CH3. The AFM images results showed the membrane surfaces have micro-/nanometer crater-like protrusions. Those protrusions contributed for the rough surface of membrane, and the root mean square (rms) roughness was about 350.9nm. The hydrophobic groups and the surface roughness structure together lead to the super-hydrophobicity of the porous membrane.