Surface Modification of Polypropylene Microporous Membrane by Atmospheric-Pressure Plasma Immobilization of N,N-dimethylamino Ethyl Methacrylate

摘要

Surface modification of polypropylene microporous membrane (PPMM) was performedby atmospheric pressure dielectric barrier discharge plasma immobilization of N,Ndimethylaminoethyl methacrylate (DMAEMA). Structural and morphological changes on themembrane surface were characterized by attenuated total reflection-Fourier transform infraredspectroscopy (FT-IR/ATR), X-ray photoelectron spectroscope (XPS) and field emission scanningelectron microscopy (FE-SEM). Water contact angles of the membrane surfaces were also measuredby the sessile drop method. Results reveal that both the plasma-treating conditions and theadsorbed DMAEMA amount have remarkable effects on the immobilization degree of DMAEMA.Peroxide determination by 1,1-diphenyl-2-picrvlhydrazyl (DPPH) method verifies the exsistenceof radicals induced by plasma, which activize the immobilization reaction. Pure water contactangle on the membrane surface decreased with the increase of DMAEMA immobilization degree,which indicates an enhanced hydrophilicity for the modified membranes. The effects of immobilizationdegrees on pure water fluxes were also measured. It is shown that pure water fluxes firstincreased with immobilization degree and then decreased. Finally, permeation of bovine serumalbumin (BSA) and lysozyme solution were measured to evaluate the antifouling property of theDMAEMA-modified membranes, from which it is shown that both hydrophilicity and electrostaticrepulsion are beneficial for membrane antifouling.