Stability and Thermal Conductivity Enhancement of Silver Nanofluids with Gemini Surfactants

Abstract

Highly dispersed silver nanofluids were prepared using cationic gemini surfactants (n-6-n) as stabilizers in aqueous solution. The influences of alkyl chain length in the structure of cationic gemini surfactants on the preparation and stability of the silver nanofluids are presented. The thermal conductivity enhancement of the silver nanofluids was determined by means of the point heat source method. The effects of polar solvents and temperatures on the stability of the silver nanofluids were investigated. The size of the silver nanoparticles is uniform, and their average diameter is about 10–20 nm. The silver nanoparticles could be transferred from an aqueous phase into a dichloromethane or chloroform phase and still be dispersed well. The stability of silver nanoparticles can be ordered as G16-6-16–Ag > G14-6-14–Ag > G12-6-12–Ag.