Stability is the key for nanofluids to enter applications: Reflections from a case study on PDMS/TiO2 nanofluids

Abstract

This work examines the stability and the density, dynamic viscosity, specific heat capacity and thermal conductivity of a series of polydimethylsiloxane-based nanofluids with TiO2 nanoparticles. Even though polydimethylsiloxane (silicone) is a promising heat transfer fluid for concentrating solar power, its non-polar, aprotic nature complicates the production of stable nanofluids without surfactants or pH control. This, in turn, limits the efficiency and lifespan of these nanofluids. The case study dedicates some space for reflection about the stability challenge for the research community working on nanofluids at fundamental and applied levels. A robust experimental protocol is sketched for quality control in the design of nanofluids, stressing the need for a quantitative assessment of stability before thermal performance is appraised.