PH-induced motion control of self-propelled oil droplets using a hydrolyzable gemini cationic surfactant

Shingo Miura, Taisuke Banno, Taishi Tonooka, Toshihisa Osaki, Shoji Takeuchi, Taro Toyota

研究成果: Article査読

41 被引用数 (Scopus)


Self-propelled motion of micrometer-sized substances has drawn much attention as an autonomous transportation system. One candidate vehicle is a chemically driven micrometer-sized oil droplet. However, to the best of our knowledge, there has been no report of a chemical reaction system controlling the three-dimensional motion of oil droplets underwater. In this study, we developed a molecular system that controlled the self-propelled motion of 4-heptyloxybenzaldehyde oil droplets by using novel gemini cationic surfactants containing carbonate linkages (2G12C). We found that, in emulsions containing sodium hydroxide, the motion time of the self-propelled oil droplets was longer in the presence of 2G12C than in the presence of gemini cationic surfactants without carbonate linkages. Moreover, in 2G12C solution, oil droplets at rest underwent unidirectional, self-propelled motion in a gradient field toward a higher concentration of sodium hydroxide. Even though they stopped within several seconds, they restarted in the same direction. 2G12C was gradually hydrolyzed under basic conditions to produce a pair of the corresponding monomeric surfactants, which exhibit different interfacial properties from 2G12C. The prolonged and restart motion of the oil droplets were explained by the increase in the heterogeneity of the interfacial tension of the oil droplets.

出版ステータスPublished - 2014 7月 15

ASJC Scopus subject areas

  • 材料科学一般
  • 凝縮系物理学
  • 表面および界面
  • 分光学
  • 電気化学


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