Bae, B Kim, D Kim, HJ Lim, TH Oh, IH Ha, HY 2024-01-21T03:32:50Z 2024-01-21T03:32:50Z 2021-09-02 2006-03-09 1520-6106 https://pubs.kist.re.kr/handle/201004/135659 The perfluorosulfonic acid membranes which are used in direct methanol fuel cells were modified with argon plasma under various conditions, and the physicochemical and transport properties of the resulting membranes were investigated using various analytical techniques. The plasma treatment was found to change the surface morphology and physicochemical properties of the membranes. The surface roughness of the membranes was increased by the etching effect of plasma. From the FTIR and XPS analyses, the incorporation of new oxygen functionalities, such as the peroxide group, was confirmed. The breakage of both the sulfonic acid groups and ether linkages were also found to cause an increase in the equivalent weight of the modified skin layer of the membrane. The incident water contact angle of the modified membrane in a dry state decreased with an increased plasma treatment, because of the hydrophilic groups that developed on the membrane surface. The time-dependent water contact angle, however, increased in proportion to the extent of the plasma treatment, due to the reduced concentration of sulfonic acid groups. Although the equilibrium water uptake of the modified membrane was almost invariable because of the negligible thickness of the modified skin layer, the transport properties of the membrane such as methanol permeability and proton conductivity were significantly reduced. English AMER CHEMICAL SOC PROTON TRANSPORT NAFION XPS FILMS WATER Surface characterization of argon-plasma-modified perfluorosulfonic acid membranes Article 10.1021/jp055159i 1 JOURNAL OF PHYSICAL CHEMISTRY B, v.110, no.9, pp.4240 - 4246 JOURNAL OF PHYSICAL CHEMISTRY B 110 9 4240 4246 scie scopus 000235944500059 2-s2.0-33645746650 Chemistry, Physical Chemistry Article PROTON TRANSPORT NAFION XPS FILMS WATER Direct methanol fuel cell Nafion membrane plasma modification methanol crossover water uptake