Study Of Polyvinylidene Fluoride Membrane Modified With Collagen By Plasma

Poly(vinylidene fluoride)(PVDF)is a burgeoning and preferred membrane material because of its high mechanical stability,excellent chemical resistance,well-controlled porosity and excellent electrical resistance.Collagen has excellent physical properties and biological characteristics,which makes it suitable for many applications,such as medicine,biomedical material and food.The basic collagen molecule has three intertwined polypeptide chains to form a triple helix,and contains a lot of amino acids.Collagen immobilization on PVDF membrane can improve the hydrophilicity and biocompatibility of membrane.In this work,PVDF membrane was modified by He low-temperature plasma polymerization with collagen.The effects of plasma treatment and grafting treatment on the structure and properties of PVDF membrane were studied.The surface modification of PVDF membrane was investigated by using pure water flux,contact angle measurement,graft degree,Fourier Transform Infrared Spectroscopy(FTIR)and bovine serum albumin(BSA)adsorption.The article contents are as follows:1.Plasma exposure time,plasma RF power,graft temperature,collagen concentration and graft time were studied in this part.The hydrophilicity of modified PVDF membrane(P-PVDF)and PVDF membrane grafted with collagen(G-PVDF)was investigated.The results show that P-PVDF membrane has the maximum pure water flux of 149.1 Lm-1·h-1 and the minimum contact angle of 59.8°.The P-PVDF membrane was prepared in plasma exposure time of 90s and plasma radio frequency power of 50W.C-PVDF membrane has the maximum pure water flux of 197.4 L·m-2·h-1 and the minimum contact angle of 47.8°.The C-PVDF membrane was prepared in plasma exposure time of 90s,plasma radio frequency power of 50W,graft temperature of 35 ℃,collagen concentration of 15 g/L and graft time of lh.2.Collagen was cross-linked by glutaraldehyde on PVDF membranes(C-PVDF).The pure water flux of C-PVDF membrane first increases and then decreases with increasing glutaraldehyde concentration,and the pure water flux reaches the maximum of 245.6 L·m-2·h-1 at the concentration of 0.4%.The pure water flux of C-PVDF membrane first increases and then decreases with increasing cross-linking time,and the pure water flux reaches the maximum at Ih.The pure water flux of C-PVDF membrane reaches the maximum of 271.9 L·m-2·j-1 at the cross-linking temperature of 35℃ and decreases after 35℃.3.Effects of pH value on pure water flux,removal rate of BSA and BSA adsorption capacity of PVDF flat membranes and the PVDF hollow fiber membranes were discussed in this part.The pH values of pure water and BSA solution were changed.The water flux of the PVDF flat membranes decreases gradually with pH value increasing.The water flux becomes stable when pure water is alkaline.The removal rate of BSA of the C-PVDF membrane decreases from 97.4%to 85.2%with pH value increasing,and the other flat membranes have less influence on the removal rate of BSA.BSA adsorption capacity of C-PVDF flat membrane is the lowest compared to other flat membranes.The water flux of C-PVDF hollow fiber membrane is higher than that of G-PVDF,and that of original PVDF hollow fiber membrane is the lowest.Cell culture of the different PVDF plat membranes by using MTT colorimetric method was investigated.MTT assay shows C-PVDF membrane display good biocompatibility.The research results provide a new method to improve the hydrophilicity of PVDF membrane.It also provides a possible method to graft PVDF membrane with collagen and this membrane can be applied in biomedical field.