Chemomechanical Motion of a Self-Oscillating Gel in a Protic Ionic Liquid

Tsukuru Masuda; Takeshi Ueki; Ryota Tamate; Ko Matsukawa; Ryo Yoshida

doi:10.1002/anie.201809413

Chemomechanical Motion of a Self-Oscillating Gel in a Protic Ionic Liquid

Angew Chem Int Ed Engl. 2018 Dec 17;57(51):16693-16697. doi: 10.1002/anie.201809413. Epub 2018 Nov 20.

Authors

Tsukuru Masuda^{1

2}, Takeshi Ueki³, Ryota Tamate^{1

4}, Ko Matsukawa¹, Ryo Yoshida¹

Affiliations

¹ Department of Materials Engineering, School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-8656, Japan.
² Present address: Department of Life Science and Technology, Tokyo Institute of Technology, 4259 B-57, Nagatsuta, Yokohama, 226-8501, Japan.
³ WPI Research Center International Center for Materials Nanoarchitectonics (MANA), National Institute of Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan.
⁴ Present address: Department of Chemistry and Biotechnology, Yokohama National University, 79-5 Tokiwadai, Hodogaya-ku, Yokohama, 240-8501, Japan.

PMID: 30378225
DOI: 10.1002/anie.201809413

Abstract

An autonomous swelling-deswelling oscillation of polymer gels in a hydrated protic ionic liquid (PIL) as a proton source for the Belousov-Zhabotinsky (BZ) reaction is presented. Methylammonium hydrogen sulfate ([maH⁺ ][HSO₄ ^- ]) was employed as the PIL because it provides stable redox oscillation in the BZ reaction. Due to the significantly higher pK_a for [maH⁺ ][HSO₄ ^- ] than those for conventional proton sources for the BZ reaction, chemomechanical oscillation can be expected under weaker acidic conditions. The self-oscillating polymer was designed as a ternary random copolymer of N-isopropylacrylamide, N-(3-aminopropyl)methacrylamide, and the Ru(bpy)₃ moiety as a catalyst for the BZ reaction. The copolymer exhibited spontaneous soluble-insoluble oscillation in hydrated [maH⁺ ][HSO₄ ^- ] containing NaBrO₃ and malonic acid. Macroscopic swelling-deswelling oscillation of the porous bulk gel prepared by covalently connecting microgel particles was also observed.

Keywords: gels; oscillating chemical reactions; polymers; protic ionic liquids; ruthenium.

Abstract

Grants and funding