Investigation on interfacial properties of conventional and functional modified TiO2/water nanofluids

The interfacial properties of conventional and functional modified nanofluids, including tension and contact angle, are investigated experimentally. The conventional nanofluids are prepared by mixing pure TiO2 nano -particles into water containing surfactants, and the functional modified nanofluids are prepared by adding 3-aminpropyltriethoxysilane (APTS) or gamma-glycidoxypropyltrimethoxysilane (GPTMS) treated nanoparticles into water. The results show that the surface tension of both conventional and functional modified nanofluids shows a decreasing trend with the elevating nanoparticle concentration and temperature. The surface roughness of copper plates as well as the nanoparticle loading would both have obvious effects on the contact angle. The surface tension and contact angle of conventional nanofluids decrease with the increasing surfactant concen-tration. Among all tested samples, the APTS modified nanofluids have larger surface tension and contact angle, which indicates a poorer wettability. The sodium dodecyl sulfate (SDS) added nanofluids have better wettability, in which smaller surface tension and contact angle are found.