Non‐Newtonian Thermosensitive Nanofluid Based on Carbon Dots Functionalized with Ionic Liquids

• Published in: Small (Weinheim an der Bergstrasse, Germany) Germany), 2020-07, Vol.16 (28), p.e1907661-n/a
• Main Authors: Gonçalves, Helena M. R., Pereira, Rui F. P., Lepleux, Emmanuel, Pacheco, Louis, Valente, Artur J. M., Duarte, Abel J., Zea Bermudez, Verónica
• Format: Article
• Language: English
• Subjects: Carbon dots; Chitin; Electromagnetic absorption; Energy transfer; Ionic liquids; Nanofluids; Nanotechnology; plasmonic effect; Raw materials; self‐improving ionic conductivity; Sensitivity; Substrates; Thin films; Wettability
• ISSN: 1613-6810; 1613-6829
• DOI: 10.1002/smll.201907661

Non‐Newtonian nanofluids present outstanding features in terms of energy transfer and conductivity with high application in numerous areas. In this work, non‐Newtonian nanofluids based on carbon dots (Cdots) functionalized with ionic liquids (ILs) are developed. The nanofluids are produced using a simple, single‐step method where the raw materials for the Cdots synthesis are glucose and waste biomass (chitin from crab shells). The use of ILs as both reaction media and functionalization molecules allows for the development of a new class of nanofluids, where the ILs on the Cdots surface represent the base‐fluid. Here, the well‐known benign IL 1‐butyl‐3‐methylimidazolium chloride ([Bmim]Cl) and a novel home‐made IL (1‐tosylate‐3‐methyl‐imidazolium triflate) [Tmi][Trif] are used. The nanofluids obtained from both substrates show, apart from high conductivity and viscosity, light absorption, and good wettability, an appealing thermal sensitivity behavior. This thermal sensitivity is preserved even when applied as thin films on glass slides and can be boosted using the surface plasmon resonance effect. The results reported demonstrate that the new Cdots/IL‐based nanofluids constitute a versatile and cost‐effective route for achieving high‐performance thermosensitive non‐Newtonian sustainable nanofluids with tremendous potential for the energy coatings sector and heat transfer film systems. Here, a class of nanofluids produced using green, sustainable reaction conditions is described, where the base fluid is composed by ionic liquids that are covering the surface of Cdots. The produced nanofluids present appealing optoelectric features that can be further boosted using the surface plasmonic effect. These characteristics are relevant in the nanocoating area, energy, space exploration, among others.