Applications of cationic gemini surfactant in preparing multi-walled carbon nanotube contained nanofluids

Stable homogeneous nanofluids of multi-walled carbon nanotubes (MWNTs) were prepared by using gemini cationic surfactant trimethylene-1,3-bis (dodecyldimethyl ammonium bromide), abbreviated as 12-3-12.2Br(-1),as dispersing agents. Zeta potential and FT-IR measurements were employed to investigate the adsorption mechanism of 12-3-12,2Br(-1) on MWNTs. The interactions between MWNTs and 12-3-12,2Br(-1) through hydrophobic segments cause hydrophilic MWNT-suspended medium interfaces with high positive charges, which enables the nanofluids to be stable for long periods. At relatively low temperatures the superfluous surfactant molecules form stable layer or column micelles, making an increase in the viscosity of nanofluids. Only 0.6wt% gemini surfactant was used to obtain 0.5 wt% MWNT dispersions. The dispersions show no MWNTs precipitation for at least 5 weeks. (C) 2008 Elsevier B.V. All rights reserved.