Preparation of water-dispersible Janus nanosheets from K4Nb6O17·3H2O and their behaviour as a two-dimensional surfactant on air-water and water-toluene interfaces

Ryoko Suzuki, Tomoki Nagai, Emika Onitsuka, Naokazu Idota, Masashi Kunitake, Taisei Nishimi, Yoshiyuki Sugahara*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

Abstract

K4Nb6O17·3H2O-based Janus nanosheets with water dispersibility and surface activity were prepared via sequential regioselective surface modification. To provide individual Janus nanosheets with these two properties, phenylphosphonic acid and phosphoric acid were utilized for surface modification at interlayers I and II of K4Nb6O17·3H2O, respectively, and the resulting product was exfoliated into single-layered nanosheets by ultrasonication in water. The resulting aqueous dispersion of the Janus nanosheets showed lower surface tension than pure water, confirming that the Janus nanosheets had surface activity. An o/w emulsion was formed using the Janus nanosheet aqueous dispersion and toluene. In this emulsion, characteristic phenomena, coalescence and Ostwald ripening behaviour of toluene droplets were observed; the appearance of ellipsoidal droplets during coalescence and a rapid Ostwald ripening which differ from those observed for systems using conventional surfactants, were observed. These phenomena likely originated from the unique anisotropic structures of Janus nanosheets with their nm-scale thickness and μm-range lateral size.

Original languageEnglish
Pages (from-to)3625-3635
Number of pages11
JournalDalton Transactions
Volume51
Issue number9
DOIs
Publication statusPublished - 2022 Mar 7

ASJC Scopus subject areas

  • Inorganic Chemistry

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