Residual- and Linker-Free Metal/polymer Nanofluids Prepared by Direct Deposition of Magnetron-Sputtered Cu Nanoparticles into Liquid PEG

Colloidal solutions of metal nanoparticles (NPs) are typically produced by multi-step methods using a variety of chemicals. Resultant nanofluids require extra purification steps to remove the reactions byproducts and modification steps to introduce anticoagulants for the solution stabilization. Here, we suggest a single-step method to produce nanofluid in which only two components are present: 22 nm-sized Cu NPs as a filler and polyethylene glycol (PEG, 400 g/mol) as a liquid base. The method employs magnetron sputtering to synthesize Cu NPs in a gas aggregation cluster source and their subsequent loading into vacuum-compatible PEG. The resultant nanofluid demonstrates strong plasmonic and photoluminescent activity, and shows enhanced stability over time, in contrast to conventional colloidal solutions. The approach offers an alternative for the production of nanofluids in which the processes of the NP formation are decoupled from the processes of their mixing with the liquid base. (C) 2021 Elsevier B.V. All rights reserved.