title: Thin films exhibiting multicolor changes induced by formaldehyde-responsive release of anionic dyes.
abstract: A novel methodology for the sensing of formaldehyde that displays a response using distinct and diverse color changes is reported. Through copolymerization of a primary amine monomer with additional co-monomers on a pattern-printed microscope slide, primary amine-containing thin films were obtained. After the absorption of a range of colors of anionic dyes, the thin films were immersed in aqueous formaldehyde solutions. It was demonstrated that the color of the thin films changed depending on the formaldehyde concentration in the solution. As the anionic dyes were released from the thin films at varying formaldehyde concentrations, a set of thin films exhibiting a range of color-change patterns was observed. The response selectivity of the thin films towards carbonyl compounds was examined, and sensitivity in the order of formaldehyde»acetaldehyde>acetone was observed. In addition, the effect of amine structure was examined, and it was found that thin films bearing tertiary amino groups show virtually no formaldehyde response. These observations clearly indicate that the existence of primary amino groups is essential for color changes to be observed, and that the formation of an imine is the crucial step in generating a response against formaldehyde. The formaldehyde-responsive system presented herein is advantageous, as its preparation is relatively simple and does not require complex organic synthesis. In addition, a wide range of anionic dyes is compatible with the system, and can be selected in terms of color, charge, toxicology profile, and cost, for example.
authors.affiliation: Department of Biotechnology and Environmental Chemistry, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Denda
authors.affiliation: Department of Biotechnology and Environmental Chemistry, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Mizutani
authors.affiliation: Department of Biotechnology and Environmental Chemistry, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507, Japan.
authors.forename: Mizuki
authors.initials: M
authors.lastname: Iijima
authors.affiliation: Department of Biotechnology and Environmental Chemistry, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Nakahashi
authors.affiliation: Department of Biotechnology and Environmental Chemistry, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507, Japan.
authors.forename: Hiroki
authors.initials: H
authors.lastname: Yamamoto
authors.affiliation: Department of Biotechnology and Environmental Chemistry, Kitami Institute of Technology, 165 Koen-cho, Kitami, Hokkaido 090-8507, Japan. Electronic address: kanekiyo@mail.kitami-it.ac.jp.
authors.forename: Yasumasa
authors.initials: Y
authors.lastname: Kanekiyo
mesh_terms: D000588:Amines / Q000737:chemistry; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation*; D003116:Color; D004396:Coloring Agents / Q000737:chemistry*; D005557:Formaldehyde / Q000032:analysis* / Q000737:chemistry*; D058105:Polymerization
chemical_list: D000588:Amines; D004396:Coloring Agents; D005557:Formaldehyde
keywords: Colorimetric; Dye; Formaldehyde; Imine; Sensor; Thin film