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

Citation:

Manne, S. ; Schaffer, T. E. ; Huo, Q. ; Hansma, P. K. ; Morse, D. E. ; Stucky, G. D. ; Aksay, I. A. Gemini surfactants at solid-liquid interfaces: Control of interfacial aggregate geometry. Langmuir 1997, 13, 6382-6387.

Date Published:

Nov

Type of Article:

Article

ISBN Number:

0743-7463

Accession Number:

WOS:A1997YJ33100010

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.

Last updated on 07/02/2018