Self-motion of a camphoric acid boat sensitive to the chemical environment

Hayashima, Yuko; Nagayama, Masaharu; Doi, Yukie; Nakata, Satoshi; Kimura, Maya; Iida, Masayasu

doi:10.1039/b108686c

Cited by 46 publications

(69 citation statements)

References 36 publications

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“…we combine the evolution equations for the film thickness profile (11) and the field of adsorbate coverage (12) with the reaction term (14) and the disjoining pressure (13).…”

Section: Results For Model I (Only Adsorption)mentioning

confidence: 99%

“…Small pieces of camphor that move on a liquid surface by emitting a surfactant have also been studied for centuries [10,11,12,13]. More recently oil droplets containing volatile additives and interacting droplets of different volatile oils have been reported to move on solid surfaces due to the solutal Marangoni effect caused by evaporation/condensation [14].…”

Section: Introductionmentioning

confidence: 99%

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Self-propelled running droplets on solid substrates driven by chemical reactions

2005

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We study chemically driven running droplets on a partially wetting solid substrate by means of coupled evolution equations for the thickness profile of the droplets and the density profile of an adsorbate layer.Two models are introduced corresponding to two qualitatively different types of experiments described in the literature. In both cases an adsorption or desorption reaction underneath the droplets induces a wettability gradient on the substrate and provides the driving force for droplet motion. The difference lies in the behavior of the substrate behind the droplet. In case I the substrate is irreversibly changed whereas in case II it recovers allowing for a periodic droplet movement (as long as the overall system stays far away from equilibrium). Both models allow for a non-saturated and a saturated regime of droplet movement depending on the ratio of the viscous and reactive time scales. In contrast to model I, model II allows for sitting drops at high reaction rate and zero diffusion along the substrate. The transition from running to sitting drops in model II occurs via a super-or subcritical drift-pitchfork bifurcation and may be strongly hysteretic implying a coexistence region of running and sitting drops.

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“…we combine the evolution equations for the film thickness profile (11) and the field of adsorbate coverage (12) with the reaction term (14) and the disjoining pressure (13).…”

Section: Results For Model I (Only Adsorption)mentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Self-propelled running droplets on solid substrates driven by chemical reactions

2005

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“…Intermittent oscillatory motion for a camphoric acid boat may be induced by the following mechanisms. 22 The camphoric acid molecules, which develop from the camphoric acid scraping, are ionized with phosphate ions, i.e., R(COOH) 2 + 2HPO 4 2− → R(COO − ) 2 + 2H 2 PO 4 − , around the aqueous surface (Step I). Therefore, the boat does not move.…”

Section: Mechanism Of the Characteristic Motion Coupled With The Chemmentioning

confidence: 99%

“…HA is ionized as A − with B around the air/water interface. 22 Therefore, we can obtain the following reaction diffusion systems: The function F (mol m -2 s -1 ) reflects the development of a molecular layer of HA from the disk to the air/water interface. Although we approximate the disk as a material point in eq.3,…”

Section: Numerical Simulation Of the Mode-change In The Self-motion Dmentioning

confidence: 99%

“…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%

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Bifurcation of self-motion depending on the reaction order

Nagayama

Yadome

Murakami

et al. 2009

Phys. Chem. Chem. Phys.

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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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Nanotechnologie mit weichen Materialien

Hamley

2003

Angewandte Chemie

101

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Die Natur nutzt die Selbstorganisation weicher Materialien auf vielfache Weise, um Zellmembranen, Biopolymerfasern oder Viren aufzubauen. Auch der Mensch ist seit kurzem in der Lage, Materialien im Nanomaßstab zu entwickeln, entweder durch Steuerung auf atomarer oder molekularer Ebene (Top‐Down) oder durch Selbstorganisation (Bottom‐Up). Die Selbstorganisation weicher Materialien kann genutzt werden, um vielfältige Nanostrukturen für die verschiedensten Anwendungen herzustellen. Die Vielfalt der Strukturen erklärt sich aus den schwachen Ordnungen, die wiederum auf nichtkovalenten Wechselwirkungen beruhen. Damit kommt der thermischen Energie eine besondere Bedeutung zu, da sie Übergänge zwischen Phasen mit unterschiedlichen Ordnungen ermöglicht. Die Stärken der Selbstorganisation lassen sich für die Herstellung von Nanopartikeln und ‐strukturen, der Entwicklung von Nanomotoren, der Nutzung der Biomineralisation bis hin zur Entwicklung funktionalisierter Übertragungsvektoren nutzen.

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Self-motion of a camphoric acid boat sensitive to the chemical environment

Cited by 46 publications

References 36 publications

Self-propelled running droplets on solid substrates driven by chemical reactions

Self-propelled running droplets on solid substrates driven by chemical reactions

Bifurcation of self-motion depending on the reaction order

Nanotechnologie mit weichen Materialien

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