Self-Oscillation of Polymer Chains with Rhythmical Soluble-Insoluble Changes

Abstract

Self-oscillation of polymer chains in an aqueous solution has been achieved. The ruthenium catalyst for the Belousov-Zhabotinsky reaction was polymerized by using N-isopropylacrylamide and dissolved into the solution containing the BZ substrates. Periodical soluble-insoluble changes of the polymer chain were spontaneously induced by the BZ reaction. The conformational oscillations of the polymer were measured as the optical transmittance changes of the solution. This is the first report that rhythmical and reversible soluble-insoluble changes of polymer chains are realized under constant and homogeneous conditions. The transducing system from chemical energy of the BZ reaction to optical information has been constructed.

Bifurcation of self-motion depending on the reaction order

“…Several artificial systems that exhibit self-motion under conditions of chemical nonequilibrium have been studied experimentally [2][3][4][5][6][7][8][9][10][11][12][13][14][15] and theoretically [16][17][18][19] under almost isothermal conditions.…”

Development of self-oscillating polymers and gels with autonomous function

“…32 Figure 9A shows the oscillation profiles of transmittance for a polymer solution that consists of linear poly(NIPAAmco-Ru(bpy) 3 2+ ), MA, NaBrO 3 and HNO 3 at constant temperatures. The wavelength (570 nm) at the isosbestic point of reduced and oxidized states was used to detect the optical transmittance changes based on soluble-insoluble changes of the polymer and not on the redox changes of the Ru(bpy) 3 moiety.…”

“…[28][29][30] In the case of the uncrosslinked linear polymer, the polymer undergoes spontaneous cyclic solubleinsoluble changes, and the transmittance of the polymer solution oscillates autonomously. 32 In addition, submicron-sized self-oscillating microgel beads were prepared by a precipitation polymerization method. [35][36][37][38][39][40] To realize nanoactuators that exhibit autonomous oscillation on a nanometer scale (nanooscillator), using the linear polymer chain or microgels, their oscillating behavior was investigated through the optical transmittance or viscosity changes [39][40][41] of the polymer solution or microgel dispersions.…”

Effect of polymer concentration on the lifetime and transmittance behavior of a self-oscillating polymer chain with a high lower critical solution temperature

“…In this study, we synthesized a self-oscillating polymer chain, covalently bonded to the transition-metal catalyst moiety [Ru(bpy)3], to undergo a periodical transmittance change induced by the BZ reaction [9][10][11][12][13][14][15][16][17][18][19][20][21]. In this latter reaction, a periodical change in the solubility of the polymer chain was synchronized with the periodical redox change in the Ru(bpy)3 moiety.…”

“…This polymer chain undergoes transmittance self-oscillation in a wide temperature range when compared to the conventional self-oscillating polymer chain comprising a poly(Nisopropylacrylamide) [poly(NIPAAm)] main-chain [22][23]. Previous investigations have employed the latter self-oscillating main-chain with an LCST of ~32 ℃ [10][11][12][13][14][15][16][17][18][19][20][21]. Moreover, for the NIPAAm-based self-oscillating polymer chain {poly[NIPAAm-co-Ru(bpy)3]}, the LCST in the reduced state is lower than that of poly(NIPAAm) because of the low solubility of the reduced Ru(bpy)3 moiety [19].…”