Preparation of MWNT/TiO2 Nanofluids and Study of its Thermal Conductivity and Stability

In this study, functionalized multi-walled carbon nanotubes using mixed acid treatment were synthesized using solvothermal method by TiCl4 as a precursor and the thermal conductivity enhancement of MWNT-TiO2 nanofluids in various temperatures were compared. The treated nanotubes have been characterized using Fourier Transform Infrared Spectroscopy (FTIR). Hybrid materials were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that MWNTs are uniformly decorated with anatase nanocrystals. Temperature effects on thermal conductivity of MWNT-TiO2 nanofluids at different concentrations have been studied. The best result showed enhancement of thermal conductivity around 12.1% for the sample with 0.08 wt% of MWNT-TiO2 compared to distilled water at 36°C and 13. 71% at 52°C. Also, zeta potential of 0.02 wt% nanofluids and particle size distribution of nanoparticle were measured.