Effect of ultrasonication time on microstructure, thermal conductivity, and viscosity of ionanofluids with originally ultra-long multi-walled carbon nanotubes

Bertrand Jóźwiak; Heather F Greer; Grzegorz Dzido; Anna Kolanowska; Rafał Jędrysiak; Justyna Dziadosz; Marzena Dzida; Sławomir Boncel

doi:10.1016/j.ultsonch.2021.105681

Effect of ultrasonication time on microstructure, thermal conductivity, and viscosity of ionanofluids with originally ultra-long multi-walled carbon nanotubes

Ultrason Sonochem. 2021 Sep:77:105681. doi: 10.1016/j.ultsonch.2021.105681. Epub 2021 Jul 25.

Authors

Bertrand Jóźwiak¹, Heather F Greer², Grzegorz Dzido³, Anna Kolanowska⁴, Rafał Jędrysiak⁴, Justyna Dziadosz⁵, Marzena Dzida⁶, Sławomir Boncel⁷

Affiliations

¹ Silesian University of Technology, Department of Organic Chemistry, Bioorganic, Chemistry and Biotechnology, Bolesława Krzywoustego 4, 44-100 Gliwice, Poland. Electronic address: bertrand.jozwiak@polsl.pl.
² University of Cambridge, Department of Chemistry, Cambridge CB2 1EW, UK.
³ Silesian University of Technology, Department of Chemical Engineering and Process Design, Marcina Strzody 7, 44-100 Gliwice, Poland.
⁴ Silesian University of Technology, Department of Organic Chemistry, Bioorganic, Chemistry and Biotechnology, Bolesława Krzywoustego 4, 44-100 Gliwice, Poland.
⁵ University of Silesia in Katowice, Institute of Chemistry, Szkolna 9, 40-006 Katowice, Poland.
⁶ University of Silesia in Katowice, Institute of Chemistry, Szkolna 9, 40-006 Katowice, Poland. Electronic address: marzena.dzida@us.edu.pl.
⁷ Silesian University of Technology, Department of Organic Chemistry, Bioorganic, Chemistry and Biotechnology, Bolesława Krzywoustego 4, 44-100 Gliwice, Poland. Electronic address: slawomir.boncel@polsl.pl.

Abstract

The stability along with thermal and rheological characteristics of ionanofluids (INFs) profoundly depend on the protocol of preparation. Therefore, in this work, the effect of ultrasonication time on microstructure, thermal conductivity, and viscosity of INFs containing 0.2 wt% of originally ultra-long multi-walled carbon nanotubes (MWCNTs) and four different ILs, namely 1-propyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, 1-ethyl-3-methylimidazolium thiocyanate, or 1-ethyl-3-methylimidazolium tricyanomethanide, was studied. The INFs were obtained by a two-step method using an ultrasonic probe. The ultrasonication process was performed for 1, 3, 10, or 30 min at a constant nominal power value of 200 W. The obtained results showed that for the shortest sonication time, the highest thermal conductivity enhancement of 12% was obtained. The extended sonication time from 1 to 30 min caused the cutting of MWCNTs and breaking the nanoparticle clusters, leading to a decrease in the average length of the nanotube bundles by approx. 70%. This resulted in a decline in thermal conductivity even by 7.2% and small deviations from the Newtonian behavior of INFs.

Keywords: Ionanofluids; Microstructure; Thermal conductivity; Ultrasonication time; Viscosity.