Gemini surfactants at solid-liquid interfaces: Control of interfacial aggregate geometry

S. Manne, T. E. Schäffet, Q. Huo, P. K. Hansma, D. E. Morse, G. D. Stucky, Ilhan A. Aksay

Research output: Contribution to journalArticlepeer-review

210 Scopus citations

Abstract

Recent work has shown that conventional surfactants form ordered aggregates of well-defined shape and size at solid-liquid interfaces.1,2 Here we report interfacial aggregate structures as a function of surfactant geometry by using gemini surfactants with varying tail and spacer lengths. On the anionic cleavage plane of mica, aggregates tend to favor a lower curvature than in solution but follow the same general variation with surfactant geometry (i.e., with larger headgroup areas resulting in greater curvature). These morphologies on mica correlate well with those observed in surfactant-silicate mesophases, where electrostatic binding of headgroups also plays a dominant role. In addition, interfacial sphere-to-rod transitions are induced on mica (as in free solution) by binding with a headgroup-specific counterion. In contrast to mica, the hydrophobic cleavage plane of graphite interacts with surfactant tailgroups, giving rise to interfacial aggregates that are surface-controlled and relatively independent of surfactant geometry. This interaction is used to heterogeneously nucleate a surfactant-silicate mesophase which is interfacially controlled and differs from the bulk phase.

Original languageEnglish (US)
Pages (from-to)6382-6387
Number of pages6
JournalLangmuir
Volume13
Issue number24
DOIs
StatePublished - Nov 26 1997

All Science Journal Classification (ASJC) codes

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

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