Title: Fabrication, characterisation and stability of TiO₂ nanofluids

Authors: Yuzhen Lv; Yang Ge; Wei Zhou; Kai Yi; Chengrong Li; Jianxin Wang; Jinsha Yuan

Addresses: School of Energy, Power and Mechanical Engineering, North China Electric Power University, Beijing, 102206, China; State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing, 102206, China ' State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing, 102206, China ' School of Chemistry and Environment Science, Beihang University, Beijing, 100191, China ' School of Energy, Power and Mechanical Engineering, North China Electric Power University, Beijing, 102206, China ' State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources, North China Electric Power University, Beijing, 102206, China ' School of Energy, Power and Mechanical Engineering, North China Electric Power University, Beijing, 102206, China ' School of Electrical Engineering, North China Electric Power University, Baoding, 071003, China

Abstract: TiO₂ nanoparticles modified by oleic acid were prepared and dispersed into mineral oil to synthesise TiO₂ nanofluids. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM) analyses indicated that the TiO₂ nanoparticles are single crystals with an average diameter of 6 nm. Measurements on the stability of nanoparticle dispersion in the base oil were performed by testing UV-Vis absorption spectra of nanofluids aged at a working temperature of 80°C for 100 days. In addition, an AC breakdown test was carried out to further evaluate the stability of nanofluids. The obtained results show that the intensity of the UV absorption peak of nanofluid aged for 100 days has no obvious change in comparison with that of the fresh one. In particular, the ratio of the AC breakdown voltage of the aged nanofluid to the fresh one is still up to 98.6%. TiO₂ nanofluids exhibit good colloidal stability at the working temperature. Fourier transform infrared spectra (FTIR) and thermogravimetric method (TG) analyses demonstrate that oleic acid anchors on the nanoparticle surface mainly by a chemisorption. This effective surface functionalisation of nanoparticles greatly enhances the stability of TiO₂ nanofluids.

Keywords: TiO2 nanoparticles; titanium dioxide; titania; nanofluids; surface modification; breakdown strength; nanotechnology; oleic acid; mineral oil; colloidal stability.

DOI: 10.1504/IJNT.2016.080363

International Journal of Nanotechnology, 2016 Vol.13 No.10/11/12, pp.870 - 880

Published online: 16 Nov 2016 *

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