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Download fileSelf-Propelled Motion of a Coumarin Disk Characteristically Changed in Couple with Hydrolysis on an Aqueous Phase
journal contribution
posted on 2019-04-22, 00:00 authored by Satoshi Nakata, Yasutaka Irie, Nobuhiko J. SuematsuIn this study, a
coumarin disk was examined as a simple self-propelled
object under a chemical reaction. A coumarin disk placed on an aqueous
phase containing Na3PO4 as a base exhibited
continuous and oscillatory motion at lower and higher initial concentrations
of Na3PO4, [Na3PO4]0, respectively. In addition, the period of the oscillation
between rest and motion increased with increasing [Na3PO4]0. The mechanism of mode bifurcation between continuous
and oscillatory motion and a change in the period of oscillation were
discussed in terms of hydrolysis of coumarin and the surface tension
of the aqueous solution as a driving force. A reduced mathematical
model based on the reaction kinetics of coumarin around the air/aqueous
interface, which adequately reproduced the experimental observation,
was constructed. These results suggest that the characteristics of
the self-propelled motion were determined by the kinetics of hydrolysis.