Self-propelled motion
Variety of self-propelled objects have been developed in which solid particles and liquid droplets spontaneously move using chemical energy. In our lab., we focus on self-propelled objects driven using especially interfacial chemical energy and experimentally uncover the characteristics of such self-propelled motion. Furthermore, we try to clarify universal mechanism for self-propelled motion using mathematical models.
Self-propelled droplet including chemical states controlled by chemical oscillatory reactions
Biological systems, such as cells, include a variety of chemical reactions and decide the chemicals state of each cell. In this subject, we reproduce such self-propelled droplets in which nonlinear chemical reaction, the Belousov-Zhabotinsky (BZ) reaction, carries out. The chemical redox state of the droplet is controlled by the BZ reaction, which oscillate over time. In this result, the speed of droplet motion also oscillates over time periodically. This is potential system for realizing novel type of hierarchic systems.
【Related Videos】
“Self-propelled motion of the BZ droplet”
Self-propelled motion of the BZ droplet prepared in an oil phase including surfactant. The droplet motion depends on the redox state inside droplet, red: reduced state, blue: oxidized state.
【Related Articles】
- "Effect of a product on spontaneous droplet motion driven by a chemical reaction of surfactant"
- Phys. Rev. E 102, 023102 (2020).
- Link to Paper
- “Interfacial Dynamics in the Spontaneous Motion of an Aqueous Droplet”
- Langmuir 5, 11601 (2019)
- Link to Paper
- “Oscillation of Speed of a Self-Propelled Belousov－Zhabotinsky Droplet”
- JPC Lett. 7, 3424 (2016).
- Link to Paper
- “Evolution of Self-Propelled Objects: From the Viewpoint of Nonlinear Science”
- Chemistry - A Euro. J. 24, 6308
- Link to Paper
- “Nonlinear Behavior of a Self-Propelled Droplet Coupled with a Chemical Oscillatory Reaction”
- Conplexity and Synergetics
- Link to Paper
- 「化学エネルギーを利用して運動する固体・液体」
- オレオサイエンス 第15巻 (2015)
Self-propelled motion of a camphor disk and boat
Characteristics of self-propelled motion of camphor boat depends on the structure of camphor boat. If the camphor disk attached at the edge of the plastic plate, the boat continuously moves with uniform speed. On the other hand, if the disk attached at the center of the plastic plate, the boat shows interesting motion that alternates between stop and rapid motion periodically. This characteristic motion is called “intermittent motion.” The mechanism of intermittent motion can be understood by considering slow diffusion of camphor molecules under the plastic plate. This dynamics has been reproduced using mathematical model and it’s mechanism was well explained.
【Related Videos】
“Intermittent motion of a camphor boat”
A camphor boat is constructed by plastic boat and a circular camphor disk. The camphor boat spontaneously moves on water. If the camphor disk was placed at the edge of plastic, the boat moves continuously. However, if the disk was attached at the center of plastic plate, the boat alternates rapid motion and stop. This characteristic behavior is called "intermittent motion."
【Related Articles】
- "Rotational motion of a camphor disk in a circular region"
- Phys. Rev. E 99, 022211 (2019).
- Link to Paper
- "Collective Behavior of Camphor Floats Migrating on the Water Surface"
- JPSJ 86, 101012 (2017).
- Link to Paper
- "Unidirectional motion of a camphor disk on water forced by interactions between surface camphor concentration and dynamically changing boundaries"
- Phys. Chem. Chem. Phys. 19, 18767 (2017).
- Link to Paper
- "Selection of the Rotation Direction for a Camphor Disk Resulting from Chiral Asymmetry of a Water Chamber"
- JPC B 120, 9166 (2016).
- Link to Paper
- "Acceleration or deceleration of self-motion by the Marangoni effect"
- Chem. Phys. Lett 654, 92 (2016).
- Link to Paper
- "Characteristic oscillatory motion of a camphor boat sensitive to physicochemical environment"
- Choas 25, 064610 (2015).
- Link to Paper
- "Suppression and regeneration of camphor-driven Marangoni flow with the addition of sodium dodecyl sulfate"
- J. Phys. Chem. B 116, 992 (2012).
- Link to Paper
- "Mode-switching of the self-motion of a camphor boat depending on the diffusion distance of camphor molecules"
- J. Phys. Chem. C 114, 9876 (2010).
- Link to Paper
- "Intermittent motion of a camphor float depending on the nature of the float surface on water"
- Colloid Surface A 349, 74 (2009).
- Link to Paper
- 「水面滑走する自己駆動粒子のリズム運動」
- 日本物理学会誌、75 (2020).
- Link to Paper