Editors: | F. Kongoli, M. Haumann, P. Wasserscheid, T. Welton, M. Gaune-Escard, A. Angell, A. Riisager |
Publisher: | Flogen Star OUTREACH |
Publication Year: | 2018 |
Pages: | 154 pages |
ISBN: | 978-1-987820-86-7 |
ISSN: | 2291-1227 (Metals and Materials Processing in a Clean Environment Series) |
Application of functional elements and nanostructures on flexible substrates is a promising trend in electronics. Textiles represent material with great potential, whose mechanical properties (high strength, large surface area, lightness, flexibility, easy integrability into clothing) make it unique even in comparison with other flexible substrates [1,2]. Polymerized ionic liquids (PILs) was first reported in 1998, and a brief overview of their properties can be found in [3]. Their electrotransport properties are unique (when compared with other organic substances), as they are purely ionic conductors. Moreover, a majority of them can be considered to be single-ion conductors. PILs are characterized by a large capacity to absorb gases (analytes) with small molecules, especially CO<sub>2</sub> and water. On such absorption, the internal volume of the polymer is modified, and hence mobility of ions changes [4]. In the field of sensing, PILs are often employed in electrochemical sensors [5], but much rarely for sorbents in QCM sensors [6]<br />This work deals with textile chemiresistors with sensitive layers based on two types of cationic PILs / poly(tetrabutylphosphonium 3-sulfopropylacrylate) and poly(tributylhexylphosphonium 3-sulfopropyl acrylate). It includes: (i) investigation of sensitive layer - electrode contact phenomena by measuring current voltage characteristics; (ii) general characterization of these PILs by impedance spectroscopy; (iii) overview and analysis of DC- and AC- responses of PILs sensors to 10 ppm of methanol (MeOH), nitrogen dioxide (NO<sub>2</sub>), 4-bromoacetophenone (4-BAP), diethylmalonate (DEM) and yperite; and (iv) FTIR spectra of PILs— exposed and unexposed— to analyte vapours [7]. <br />Under these circumstances, the DC- responses (SDC) varied from 0.48 to 1.36, and maximum AC- responses (Spa) from 8 to 26 deg. It was shown that sensor dynamics depend mainly on molecular weight of the analyte. Moreover, the magnitude of AC-responses correlates both qualitatively and quantitatively with the dipole moment of the analysed molecule.