title: Thermal processing as a means to prepare durable, submicron thickness ionomer films for study by transmission infrared spectroscopy.
abstract: A high temperature solution processing method was adapted to prepare durable, freestanding, submicrometer thickness films for transmission infrared spectroscopy studies of ionomer membrane. The materials retain structural integrity following cleaning and ion-exchange steps in boiling solutions, similar to a commercial fuel cell membrane. Unlike commercial membrane, which typically has thicknesses of >25 μm, the structural properties of the submicrometer thickness materials can be probed in mid-infrared spectral measurements with the use of transmission sampling. Relative to the infrared attenuated total reflection (ATR) technique, transmission measurements can sample ionomer membrane materials more uniformly and suffer less distortion from optical effects. Spectra are reported for thermally processed Nafion and related perfluoroalkyl ionomer materials containing phosphonate and phosphinate moieties substituted for the sulfonate end group on the side chain. Band assignments for complex or unexpected features are aided by density functional theory (DFT) calculations.
authors.affiliation: Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, USA.
authors.forename: Chang Kyu
authors.initials: CK
authors.lastname: Byun
authors.forename: Tifani
authors.initials: T
authors.lastname: Parker
authors.forename: Chunchao
authors.initials: C
authors.lastname: Liang
authors.forename: Ian
authors.initials: I
authors.lastname: Kendrick
authors.forename: Nicholas
authors.initials: N
authors.lastname: Dimakis
authors.forename: Eugene S
authors.initials: ES
authors.lastname: Smotkin
authors.forename: Li-Mei
authors.initials: LM
authors.lastname: Jin
authors.forename: Dongqing
authors.initials: D
authors.lastname: Zhuang
authors.forename: Darryl D
authors.initials: DD
authors.lastname: DesMarteau
authors.forename: Stephen E
authors.initials: SE
authors.lastname: Creager
authors.forename: Carol
authors.initials: C
authors.lastname: Korzeniewski
mesh_terms: D017738:Alkanesulfonic Acids / Q000138:chemical synthesis / Q000737:chemistry*; D005466:Fluorocarbons / Q000138:chemical synthesis / Q000737:chemistry*; D011789:Quantum Theory; D013055:Spectrophotometry, Infrared; D013696:Temperature
chemical_list: D017738:Alkanesulfonic Acids; D005466:Fluorocarbons; C076994:perfluorooctane sulfonic acid