?ukasz SCHELLER1, Marzena DZIDA1, S?awomir BONCEL2, Bertrand JÓ?WIAK2, Grzegorz DZIDO2, Justyna DZIADOSZ1, Anna KOLANOWSKA2, Rafa? J?DRYSIAK2
1University of Silesia in Katowice, Institute of Chemistry, Katowice, Poland
2Silesian University of Technology, Faculty of Chemistry, Gliwice, Poland
Ionanofluids (INFs) composed of ionic liquids (ILs) and multi-walled carbon nanotubes (MWCNTs) exhibit interesting properties, most notably greatly increased thermal conductivity compared to the base IL. This, along with their thermal and sedimental stability, allows to propose the INFs as new heat-transfer fluids (THFs). Our recent research shows that long MWCNTs based INFs display better thermal conductivity than INFs based on short, commercial MWCNTs [1,2]. Although the long in-house MWCNTs are being substantially shortened during preparation of INFs using the two-step ultrasound sonictation method, they still remain longer than initially shorter commercialy available MWCNTs [2,3]. This allows the long MWCNTs to create subzipped networks and connect in multiple bridges with one another [1]. The length of MWCNTs is therefore mosty presumably the key factor responsible for thermal conductivity enhancement. Thus, we developed a new and repeatable, two step method for preparation of INFs without the ultrasound sonication in order to preserve the MWCNTs’ length and prevent their shortening. With this method we obtained long-term stable INFs with great thermal conductivity increase of 60% for 1.00% by weight of long in-house MWCNTs dispersed in 1-ethyl-3-methylimidazolium thiocyanate at 298.15 K - 1.5 times larger than previously reported [2]. However, a major drawback could be the viscosity of so prepared INFs being relevantly higher compared to INFs prepared using ultrasounds. Nevertheless, due to its simplicity, repeatability, feasibility and improved characteristics the new method may be a promising alternative allowing to fully exploit the potential of carbon nanotubes.
[1] M. Dzida, S. Boncel, B. Jó?wiak, H.F. Greer, M. Dulski, ?. Scheller, A. Golba, R. Flamholc, G. Dzido, J. Dziadosz, A. Kolanowska, R. J?drysiak, K. Cwynar, E. Zor?bski, C.E.S. Bernardes, M.J.V. Lourenço, C.A.N.de Castro, ACS Appl. Mater. Interfaces 2022, 14, 45, 50836-50848.
[2] B. Jó?wiak, G. Dzido, E. Zor?bski, A. Kolanowska, R. J?drysiak, J. Dziadosz, M. Libera, S. Boncel, M. Dzida, ACS Appl. Mater. Interfaces 2020, 12, 38113-38123.
[3] B. Jó?wiak, H.F. Greer, G. Dzido, A. Kolanowska, R. J?drysiak, J. Dziadosz, M. Dzida, S. Boncel, Ultrasonics Sonochemistry, 2021, 71, 105681.
This work was financially supported by the National Science Center (Poland) Grant No. 2021/41/B/ST5/00892.