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Supported and Free‐Standing Sulfonic Acid Functionalized Mesostructured Silica Films with High Proton Conductivity
Author(s) -
Supplit Ralf,
Sugawara Ayae,
Peterlik Herwig,
Kikuchi Ryuji,
Okubo Tatsuya
Publication year - 2010
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201000293
Subject(s) - thermogravimetric analysis , sulfonic acid , chemistry , fourier transform infrared spectroscopy , thermal stability , conductivity , small angle x ray scattering , silane , polymer chemistry , chemical engineering , organic chemistry , scattering , physics , optics , engineering
Sulfonic acid functionalized silica films with 2D‐hexagonal mesostructures of various channel sizes are prepared in a one‐step synthesis. A successful combination of in situ oxidation of a mercapto‐functionalized silane with an evaporation induced self‐assembly (EISA) process in the presence of amphiphilic block copolymers allows the formation of a highly structured material with a sulfonation degree of 33 %. Analysis of the mesostructure by a combination of XRD, grazing‐incidence small‐angle X‐ray scattering (GI‐SAXS), and TEM shows that 2D‐hexagonally ordered mesostructured films are obtained by optimization of the surfactant to silica precursor ratio. The tuneability of the mesochannel size is demonstrated by the use of three different surfactants. The complete oxidation of the mercapto group to sulfonic acid is confirmed by Fourier transform infrared spectroscopy (FTIR). The thermal stability of the material is investigated by coupled thermogravimetric analysis, differential temperature analysis, and mass spectrometry (TGA‐DTA‐MS). Alternating current (AC) impedance analysis of humidified samples shows high proton conductivity of up to 0.18 S cm –1 at 60 °C and 95 % relative humidity.