Self-Rotation of a Camphor Scraping on Water:  New Insight into the Old Problem

Nakata, Satoshi; Iguchi, Yasutaka; Ose, Sachie; Kuboyama, Makiko; Ishii, Toshio; Yoshikawa, Kunio

doi:10.1021/la970196p

Cited by 224 publications

(279 citation statements)

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“…We also include a dissipation term in Eq. (8). This term, written as αu t , is given to stabilize the oscillatory motions.…”

Section: Mathematical Modelmentioning

confidence: 99%

“…Spontaneous motion driven by inhomogeneity in interfacial tension is an area of study relating to active matter. [5][6][7][8][9][10][11][12][13][14][15][16] For example, alcohol droplets placed on water move spontaneously while exhibiting deformations to their shape. 17,18 Since such systems are relatively simple, it is possible to perform experiments under a broad parameter space; therefore, such a setting provides a preferable experimental framework for investigations of general aspects.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Mathematical model for self-propelled droplets driven by interfacial tension

Nagai

Tachibana

Tobe

et al. 2016

The Journal of Chemical Physics

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Articles you may be interested inNumerical study on the effects of non-dimensional parameters on drop-on-demand droplet formation dynamics and printability range in the up-scaled model Phys. Fluids 24, 082103 (2012) We propose a model for the spontaneous motion of a droplet induced by inhomogeneity in interfacial tension. The model is derived from a variation of the Lagrangian of the system and we use a time-discretized Morse flow scheme to perform its numerical simulations. Our model can naturally simulate the dynamics of a single droplet, as well as that of multiple droplets, where the volume of each droplet is conserved. We reproduced the ballistic motion and fission of a droplet, and the collision of two droplets was also examined numerically. C 2016 AIP Publishing LLC. [http://dx

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“…We also include a dissipation term in Eq. (8). This term, written as αu t , is given to stabilize the oscillatory motions.…”

Section: Mathematical Modelmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Mathematical model for self-propelled droplets driven by interfacial tension

Nagai

Tachibana

Tobe

et al. 2016

The Journal of Chemical Physics

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“…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.…”

Section: Introductionmentioning

confidence: 99%

Bifurcation of self-motion depending on the reaction order

Nagayama

Yadome

Murakami

et al. 2009

Phys. Chem. Chem. Phys.

Self Cite

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As a simple example of an autonomous motor, the characteristic features of self-motion coupled with the acid-base reaction were numerically and experimentally investigated at the air/aqueous interface. Oscillatory and uniform motion were categorized as a function of the reaction order by numerical computations using a mathematical model that incorporates both the distribution of the surface active layer developed from a material particle as the driving force and the kinetics of the acid-base reaction. The nature of the self-motion was experimentally observed for a boat adhered to a camphor derivative with a mono-or di-carboxylic acid on a phosphate aqueous phase as the base.2

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“…As a camphor particle is placed on pure water, it exhibits spontaneous motion. The mechanism of the motion is briefly described as follows [12,13]: Camphor molecules escape from the camphor particle to the water surface. Since camphor has a surface activity, the camphor molecules at the water surface reduce the surface tension.…”

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confidence: 99%

Spontaneous motion of an elliptic camphor particle

2013

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The coupling between deformation and motion in a self-propelled system has attracted broader interest. In the present study, we consider an elliptic camphor particle for investigating the effect of particle shape on spontaneous motion. It is concluded that the symmetric spatial distribution of camphor molecules at the water surface becomes unstable first in the direction of a short axis, which induces the camphor disk motion in this direction. Experimental results also support the theoretical analysis. From the present results, we suggest that when an elliptic particle supplies surface-active molecules to the water surface, the particle can exhibit translational motion only in the short-axis direction. Spontaneous motion in nonequilibrium systems has long attracted the interest of scientists because it is related to the motion of living organisms. In particular, the coupling between deformation and spontaneous motion has been actively investigated and several important and interesting studies, both experimental and theoretical, have been reported. For example, Ohta et al. proposed a generic model for the coupling between deformation and spontaneous motion by analyzing such coupling from the viewpoint of the bifurcation theory of dynamical systems [1][2][3]. Teramoto et al. studied the coupling between deformation and motion in pulse propagation in a reaction-diffusion system [4]. In experiments, cell motion is analyzed in relation to cell shape [5][6][7], and mathematical models have also been proposed for such cell deformation [8,9].For investigating the coupling between motion and deformation, one approach is to decouple them; i.e., we consider the effect of particle shape on motion. For this purpose, we chose a camphor-water system, in which a camphor particle exhibits spontaneous motion but not deformation. The camphor-water system was first reported in the 19th century [10,11]. As a camphor particle is placed on pure water, it exhibits spontaneous motion. The mechanism of the motion is briefly described as follows [12,13]: Camphor molecules escape from the camphor particle to the water surface. Since camphor has a surface activity, the camphor molecules at the water surface reduce the surface tension. It should be noted that the camphor molecules sublimate to the air, so that the profile of the surface concentration of camphor molecules at the water surface can reach a steady state. If the camphor particle is circular and does not move, the profile of the surface concentration of camphor molecules should be symmetric with respect to the center of the camphor particle. However, it is known that such a steady state can become unstable by an infinitesimal fluctuation. In such a case, motion in a certain direction at a constant velocity is stabilized and realized. Consequently, the profile of * Corresponding author: kitahata@physics.s.chiba-u.ac.jp the surface concentration becomes asymmetric [14][15][16]. This camphor-water system has attracted attention since it exhibits interesting and complicated phenomena ...

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Self-Rotation of a Camphor Scraping on Water: New Insight into the Old Problem

Cited by 224 publications

References 15 publications

Mathematical model for self-propelled droplets driven by interfacial tension

Mathematical model for self-propelled droplets driven by interfacial tension

Bifurcation of self-motion depending on the reaction order

Spontaneous motion of an elliptic camphor particle

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