Characteristic stability of bare Au-water nanofluids fabricated by pulsed laser ablation in liquids

Gold nanoparticles (Au-NPs) suspended in water where the suspension is a kind of nanofluid, were produced by pulsed laser ablation in liquids. Under the laser irradiation conditions up to 18 h, the average size of the Au-NPs ranged from 7.1 to 12.1 nm while their size-distribution tended to become narrower with effects of laser-induced fragmentation. Interestingly, the nanofluid showed an outstanding colloidal stability even after 1 month although no dispersants were used. The characteristic stability of bare Au-NPs suspension in water was found to be due to a large negative zeta potential of Au-NPs in water. The thermal conductivity of the Au-NPs (0.018 vol%)/water suspension increased by 9.3±5.4% compared to that of pure water.