Synchronized Self-Motion of Two Camphor Boats

Abstract

The synchronized self-motion of two camphor boats was investigated on a circular water route. Two kinds of synchronization, phase-locking and phase-oscillatory modes, could be produced by changing the temperature, the radius of the circular cell, and the mass of each boat. The nature of the synchronization is discussed in relation to the distribution of the camphor layer, which is an important factor in the driving force of self-motion. The essential features of synchronized motion were reproduced by a numerical calculation regarding the spatial distribution of the camphor layer at the air/water interface. We believe that the present results may be useful for realizing artificial motors or chemomechanical transducers, which mimic motor organs or organelles in living organisms under nonlinear and isothermal conditions.

Bifurcation of self-motion depending on the reaction order

“…20 Recently, we reported that the nature of the self-motion of a camphor scraping changes depending on both the internal conditions (e.g., scraping morphology and chemical structure of the camphor derivative) [21][22][23][24] and external conditions (e.g., temperature, surface tension, and the shape of the cell), [24][25][26][27][28] and the essential features of self-motion could be reproduced by a computer simulation. [21][22][23][24][25][26][27][28] In one of these studies, we reported that the mode of self-motion of a camphoric acid boat characteristically changes depending on the concentration of phosphate ion or pH in the aqueous phase, and that the characteristic mode-change between uniform, oscillatory, and no motion is coupled with the acid -base reaction. 22 In this study, we investigated the nature of self-motion depending on the reaction order of the acid-base reaction.…”

Synchronized motion of a mobile boundary driven by a camphor fragment

“…The self-motion of a camphor fragment at an air/water interface is driven by the heterogeneous distribution of the camphor molecular layer that develops from the solid fragment [18][19][20][21][22][23][24][25]. That is, the concentration of a camphor layer at a concave area of the camphor fragment is generally higher than that at a convex one; therefore the heterogeneous density distribution of a camphor layer due to the shape of a camphor fragment determines the direction of motion [18].…”

Theoretical study on the translation and rotation of an elliptic camphor particle

“…In the last decade, motions of surfactant particles, almost undeformable droplets, and that of "camphor boats" as well, have been investigated by means of mathematical modelling under certain conditions [14,20,21]. As mentioned above, they can explain the spontaneous symmetry breaking and many other phenomena, such as oscillatory motions in a linear chamber [13] and jamming in an annular channel [22][23][24].…”