AVS 49th International Symposium
    Plasma Science Wednesday Sessions
       Session PS+BI-WeA

Paper PS+BI-WeA8
Permanent Hydrophilic Modification of Porous Membranes Using Low-Temperature Plasmas

Wednesday, November 6, 2002, 4:20 pm, Room C-103

Session: Plasma Processing for Biocompatible Surfaces
Presenter: D.S. Wavhal, Colorado State University
Authors: D.S. Wavhal, Colorado State University
E.R. Fisher, Colorado State University
Correspondent: Click to Email
We have explored the use of low-temperature plasmas to modify porous polymeric membranes with the goal of creating hydrophilic surface throughout the membrane structure. One motivation for this work is to decrease membrane fouling and to eliminate the need for wetting agents in a variety of applications. Porous polyethersulfone (PES) membranes were modified by CO@sub 2@ plasma treatment and Ar-plasma treatment followed by grafting of hydrophilic monomers (acrylic acid and acrylamide), in the vapor phase. Plasma treatment and plasma induced grafting rendered a complete hydrophilicity to the entire PES membrane cross section. The hydrophilicity of the membranes treated with only the Ar-plasma is not, however, permanent. In contrast, the PES membranes treated with CO@sub 2@ plasma and the grafted membranes are found to be permanently hydrophilic (for a minimum of six months). Chemical changes to the modified PES membranes were determined with FTIR and XPS measurements. Furthermore, water bubble point measurements and electron microscopy results reveal that pore sizes of the modified membranes are slightly affected. The pore sizes of the grafted membranes at higher grafting yield are slightly decreased. Due to incorporation of polar functionalities, the glass transition temperature (T@sub g@) of modified membranes also increases. A moderate change in tensile strength of the modified membranes was observed. Most importantly, the surface of the modified membrane are less susceptible to absorbtion by bovine serum albumin (BSA) proteins and give greater flux recoveries. This suggests that the protein fouling layer is reversible because of hydrophilic nature of the modified membranes.