Physicochemical design and analysis of self-propelled objects that are characteristically sensitive to environments

Nakata, Satoshi; Nagayama, Masaharu; Kitahata, Hiroyuki; Suematsu, Nobuhiko J.; Hasegawa, Takeshi

doi:10.1039/c5cp00541h

Cited by 124 publications

(203 citation statements)

References 102 publications

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“…The profile of camphor surface concentration on water results from the balance between the inflow of camphor molecules from the disks and camphor evaporation into the air and dissolution in the water [20]. It is known that water surface tension is a decreasing function of camphor surface concentration [6,20,30]. The averaged force acting on a camphor disk is directed towards the region with the lowest camphor surface concentration around the disk.…”

Section: Methodsmentioning

confidence: 99%

“…In order to reduce the hydrodynamic flows the central part of the plastic stripe was elevated above the water level so that only the bottom surface of camphor disks had contact with water and the stripe did not touch its surface. The profile of camphor surface concentration on water results from the balance between the inflow of camphor molecules from the disks and camphor evaporation into the air and dissolution in the water [20]. It is known that water surface tension is a decreasing function of camphor surface concentration [6,20,30].…”

Section: Methodsmentioning

confidence: 99%

“…For example, comma-shaped camphor particles [6,20] and a propeller made of camphor disks and plastic plates [28] exhibit rotational motion in the direction determined by the asymmetry. In order to realize the rotational motion through spontaneous symmetry breaking, we have to introduce an axial anisotropy.…”

Section: Introductionmentioning

confidence: 99%

“…The motion caused by the spontaneous symmetry breaking is described in terms of bifurcations. It has been shown that the mathematical model based on the reaction-diffusion system in which the camphor surface concentration is coupled with the Newtonian equation for motion of the camphor particle reproduces such spontaneous symmetry breaking, which can be described as the pitchfork bifurcation [20,27].…”

Section: Introductionmentioning

confidence: 99%

“…A camphor boat and a camphor disk moving on a water surface have been intensively studied as examples of motion caused by embedded asymmetry and by spontaneous symmetry breaking, respectively [6,[18][19][20]. A camphor particle attached to a plastic plate moves in the direction opposite to the camphor-attached side, which is considered as a self-propelled particle with embedded asymmetry.…”

Section: Introductionmentioning

confidence: 99%

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Relationship between the size of a camphor-driven rotor and its angular velocity

et al. 2017

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We consider a rotor made of two camphor disks glued below the ends of a plastic stripe. The disks are floating on a water surface and the plastic stripe does not touch the surface. The system can rotate around a vertical axis located at the center of the stripe. The disks dissipate camphor molecules. The driving momentum comes from the nonuniformity of surface tension resulting from inhomogeneous surface concentration of camphor molecules around the disks. We investigate the stationary angular velocity as a function of rotor radius ℓ. For large ℓ the angular velocity decreases for increasing ℓ. At a specific value of ℓ the angular velocity reaches its maximum and, for short ℓ it rapidly decreases. Such behaviour is confirmed by a simple numerical model. The model also predicts that there is a critical rotor size below which it does not rotate. Within the introduced model we analyze the type of this bifurcation.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Relationship between the size of a camphor-driven rotor and its angular velocity

et al. 2017

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Periodic Oscillatory Motion of a Self‐Propelled Motor Driven by Decomposition of H₂O₂ by Catalase

et al. 2016

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As elf-propelled motor driven by the enzymatic reaction of catalase adsorbed onto afilter paper floating on an aqueous solution of H 2 O 2 was used to study nonlinear behavior in the motorsm otion. An increase in the concentration of H 2 O 2 resulted in ac hange from no motion to irregular oscillatory motion, periodic oscillatory motion, and continuous motion. The mechanisms underlying oscillation and mode bifurcation are discussed based on experimental results on O 2 bubblef ormation and growth on the underside of the motor.Several types of self-propelled systems have been designed and their ability to move in as mall space has been investigated;s uch systems include noble metals [1] or enzymes [2] in an aqueous solutions of H 2 O 2 ,a nd as olid particle or an organic droplet placed on an aqueous phase. [3, 4] However,most systems exhibit random or monotonic motion, and their direction of motion is determined by the initial concentration gradient or is controlled by an external force. [5] In contrast, living organisms,s uch as bacteria with flagellar motors,can variously change the direction, speed, and nature of motion while sensing the environment under essentially isothermal and non-equilibrium conditions; [6] examples include taxis and swarm behavior.T he diversity of motion in animate systems is clearly larger than that in inanimate systems.In contrast, nonlinear phenomena observed in living organisms,s uch as limit-cycle oscillation, bifurcation, and synchronization, have been well reproduced in non-living systems. [7] Therefore,t he ability of inanimate systems to induce nonlinear phenomena is important not only to enhance their diversity but also to create inanimate systems that mimic living organisms. [3] Enzymatic reactions often induce nonlinear phenomena, such as concentration oscillation, owing to the nonlinearity of the reaction kinetics. [8,9] However,todate there have been no reports of self-propelled motors coupled with enzymatic reactions that clearly show nonlinear behavior. [10] Herein, we describe the characteristic motions,s uch as oscillatory modes of motion and bifurcation of motion, of aself-propelled motor on an aqueous phase and demonstrate that the type of motion obtained depends on the concentration of H 2 O 2 .T he self-propelled motor was composed of af ilter paper (diameter:3mm) soaked with catalase.T his motor is referred to as acatalase motor.The driving force for motion is O 2 bubbles produced by the decomposition of H 2 O 2 by catalase adsorbed onto the motor. Thef ormation and growth of O 2 bubbles were monitored from the bottom of the motor to clarify the features of the motion. Them echanism underlying the characteristic motions and bifurcation of motion are discussed in relation to the formation and growth of O 2 bubbles. Figure 1s hows the time course of the self-motion of ac atalase motor with different concentrations of H 2 O 2 (C H 2 O 2 )( 1, 2, 3, and 4%)i nt he aqueous phase.S everal types of self-motion were observed, depending on C H 2 O 2 .A t C H 2 O 2 = 1%,i...

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Periodic Oscillatory Motion of a Self‐Propelled Motor Driven by Decomposition of H₂O₂ by Catalase

et al. 2016

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A self-propelled motor driven by the enzymatic reaction of catalase adsorbed onto a filter paper floating on an aqueous solution of H O was used to study nonlinear behavior in the motor's motion. An increase in the concentration of H O resulted in a change from no motion to irregular oscillatory motion, periodic oscillatory motion, and continuous motion. The mechanisms underlying oscillation and mode bifurcation are discussed based on experimental results on O bubble formation and growth on the underside of the motor.

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Physicochemical design and analysis of self-propelled objects that are characteristically sensitive to environments

Cited by 124 publications

References 102 publications

Relationship between the size of a camphor-driven rotor and its angular velocity

Relationship between the size of a camphor-driven rotor and its angular velocity

Periodic Oscillatory Motion of a Self‐Propelled Motor Driven by Decomposition of H₂O₂ by Catalase

Periodic Oscillatory Motion of a Self‐Propelled Motor Driven by Decomposition of H₂O₂ by Catalase

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Physicochemical design and analysis of self-propelled objects that are characteristically sensitive to environments

Cited by 124 publications

References 102 publications

Relationship between the size of a camphor-driven rotor and its angular velocity

Relationship between the size of a camphor-driven rotor and its angular velocity

Periodic Oscillatory Motion of a Self‐Propelled Motor Driven by Decomposition of H2O2 by Catalase

Periodic Oscillatory Motion of a Self‐Propelled Motor Driven by Decomposition of H2O2 by Catalase

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Periodic Oscillatory Motion of a Self‐Propelled Motor Driven by Decomposition of H₂O₂ by Catalase

Periodic Oscillatory Motion of a Self‐Propelled Motor Driven by Decomposition of H₂O₂ by Catalase