Microstructure of lamellar liquid crystal in Tween 85/[Bmim]PF6/H2O system and applications as Ag nanoparticle synthesis and lubrication

Abstract

Lamellar liquid crystal (Lα) was formed by room temperature ionic liquid [Bmim]PF6, nonionic surfactant Tween 85, and H2O. The microstructure of this lamellar liquid crystal was investigated by small angle x-ray diffraction (SAXD) and 2H NMR (nuclear magnetic resonance). Ag nanoparticles with relatively uniform dispersion were prepared successfully in this Lα phase. The rheological and lubrication properties of the Lα phase and the Lα/Ag nanoparticle mixed system were also investigated. The results showed that the structure strength, anti-wear capacity, and lubrication properties of the Lα phase were enhanced with an increasing amount of Tween 85, but were impaired with an increasing amount of H2O. Increasing the amount of [Bmim] PF6 could also make the structural strength weaker, but the lubrication properties of the system were improved because of the inherent lubrication properties of ionic liquid. The presence of the Ag nanoparticles in the lamellar phase could also enhance the structural strength, anti-wear capacity, and lubrication properties.