Synthesis and viscoelastic properties of gemini surfactants containing redox-active ferrocenyl groups

Jun Sugai, Norio Saito, Yutaka Takahashi, Yukishige Kondo

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

A type of electro-responsive threadlike micelle (TLM) was formed using new cationic gemini surfactants Fc 11-n-11 Fc with redox-active ferrocenyl groups in the gemini alkyl chains. By varying the alkyl spacer length, we synthesized several kinds of Fc 11-n-11 Fc -based gemini surfactants with n = 3, 4, 6, and characterized their viscoelastic behavior, surface activity, and redox properties in aqueous solutions through the use of oscillatory rheology, surface tensiometry, cyclic voltammetry, and UV–vis spectroscopic measurements. The Fc 11-4-11 Fc solution was found to form highly viscous (˜10 3 Pa⋅s) TLMs. Unlike the monomeric surfactant, the Fc 11-4-11 Fc micellar solution maintained its high viscosity even after adding extra builder and/or electrolyte agents. The surface-tensiometric measurements indicate that the effective molecular area of Fc 11-n-11 Fc at the air/water interface systematically increased with the alkyl spacer length. Using the critical packing parameters estimated with the molecular area, Fc 11-4-11 Fc is expected to be the most suitable for rod-like micellar growth. Importantly, the viscosity of Fc 11-4-11 Fc micellar solution could be decreased to that of pure water as a response to electrochemical oxidation reaction, and recovered by the subsequent re-reduction reaction. Hence, the gemini surfactants prepared in this study are a promising class of candidates for potential smart soft material applications.

Original languageEnglish
Pages (from-to)197-202
Number of pages6
JournalColloids and Surfaces A: Physicochemical and Engineering Aspects
Volume572
DOIs
Publication statusPublished - 5 Jul 2019

Keywords

  • Ferrocene
  • Gemini surfactant
  • Hydrogel
  • Redox
  • Rheology

Cite this