Study of poly(acrylic acid) grafted onto polymer surfaces modified by gas phase oxidation techniques.

摘要

Polystyrene (PS) has a wide range of technological applications due to the excellent bulk properties, but does not possess the unique surface properties for applications that require wettability, printability or cell adhesion. The following work focuses on surface modification of polystyrene by different techniques to increase the surface energy and hydrophilicity. UV photo-oxidation of polystyrene was achieved with 253.7 nm and 253.7/184.9 nm radiation in the presence of an atmospheric pressure of oxygen. Contact angle measurements were performed to confirm the surface hydrophilicity with increase in treatment times. Ozone treatment of polystyrene surface was also performed in absence of radiation.;International need for both renewable energy sources and reduction in emission levels has increased interest in a number of electrochemical devices, including batteries and fuel cells, that often use ionic conducting polymer electrolyte membranes such as NafionRTM which is a copolymer of tetrafluoroethylene and perfluoro[2-(fluorosulfonylethoxy) vinyl]ether. One disadvantage of Nafion, when applied to a direct methanol fuel cell, is methanol permeation from the anode to the cathode side resulting in poor cell performance. This thesis reports the incorporation of oxygen atoms onto the surface of Nafion-117 using vacuum UV (VUV) photo-oxidation. Acrylic acid, which is hydrophilic, was grafted to the modified PS and Nafion surface. An in-depth chemical state analysis of the surface was studied by X-ray Photoelectron Spectroscopy.