Mode changes associated with oil droplet movement in solutions of gemini cationic surfactants

Taisuke Banno, Shingo Miura, Rie Kuroha, Taro Toyota

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Micrometer-sized self-propelled oil droplets in nonequilibrium systems have attracted much attention, since they form stable emulsions composed of oil, water, and surfactant which represent a primitive type of inanimate chemical machinery. In this work, we examined means of controlling the movement of oil droplets by studying the dynamics of n-heptyloxybenzaldehyde droplets in phosphate buffers containing alkanediyl-α,ω-bis(N-dodecyl-N,N- dimethylammonium bromide) (nG12) with either tetramethylene (4G12), octaethylene (8G12), or dodecamethylene (12G12) chains in the linker moiety. Significant differences in droplet dynamics were observed to be induced by changes in the linker structure of these gemini cationic surfactants. In a phosphate buffer containing 30 mM 4G12, self-propelled motion of droplets concurrent with the formation of molecular aggregates on their surfaces was observed, whereas the fusion of oil droplets was evident in both 8G12 and 12G12 solutions. We also determined that the surface activities and the extent of molecular self-assembly of the surfactants in phosphate buffer were strongly influenced by the alkyl chain length in the linker moiety. We therefore conclude that the surface activities of the gemini cationic surfactant have important effects on the oil-water interfacial tension of oil droplets and the formation of molecular aggregates and that both of these factors induce the unique movement of the droplets.

Original languageEnglish
Pages (from-to)7689-7696
Number of pages8
JournalLangmuir
Volume29
Issue number25
DOIs
Publication statusPublished - 2013 Jun 25
Externally publishedYes

Fingerprint

Cationic surfactants
Oils
oils
surfactants
phosphates
buffers
Buffers
Phosphates
Surface-Active Agents
Surface active agents
machinery
water
emulsions
Water
self assembly
micrometers
bromides
interfacial tension
fusion
Emulsions

ASJC Scopus subject areas

  • Electrochemistry
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Materials Science(all)
  • Spectroscopy

Cite this

Mode changes associated with oil droplet movement in solutions of gemini cationic surfactants. / Banno, Taisuke; Miura, Shingo; Kuroha, Rie; Toyota, Taro.

In: Langmuir, Vol. 29, No. 25, 25.06.2013, p. 7689-7696.

Research output: Contribution to journalArticle

Banno, Taisuke ; Miura, Shingo ; Kuroha, Rie ; Toyota, Taro. / Mode changes associated with oil droplet movement in solutions of gemini cationic surfactants. In: Langmuir. 2013 ; Vol. 29, No. 25. pp. 7689-7696.
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