Investigation of thermophysical properties of nanofluids containing poly(vinyl alcohol)-functionalized graphene
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An experimental study was performed to evaluate the colloidal stability of water-based polyvinyl alcohol-functionalized few-layer graphene (water-based PVA–Gr) nanofluids and ethylene glycol-based polyvinyl alcohol-functionalized few-layer graphene (EG-based PVA–Gr) nanofluids. To this end, a liquid-phase exfoliation method was employed for mass production of graphene sheets (Gr). Then, a simple and novel method was introduced to do a direct functionalization of Gr with PVA. Surface functionality groups and morphology of PVA–Gr were analyzed by infrared spectroscopy, Raman spectroscopy and transmission electron microscopy. The results consistently confirmed the formation of PVA functionalities on Gr, while the structure of GNP has remained relatively intact. Then, UV–Vis was employed to investigate the stability of PVA–Gr in water and EG. The easily miscible PVA functionalities formed a great colloidal stability for Gr sheets. As a second criterion for having a promising coolant, thermophysical properties were measured experimentally. The thermal conductivity, density and viscosity of the nanofluids at concentrations of 0.025, 0.05 and 0.1 mass% were experimentally measured. As compared to the base fluid, the water-based PVA–Gr nanofluids show a significant enhancement at different conditions, like representing ~40% enhancement for 0.1 mass% at 40 °C. This simple and efficient procedure may play an important role for mass production of hydrophilic Gr, which be able to disperse in different solvents.
KeywordsGraphene Functionalization Heat transfer Thermophysical properties Nanofluid
List of symbols
Thermal conductivity (W m−1 K−1)
Viscosity (Pa s)
Density (kg m−3)
- 3.Amiri A, Ahmadi G, Shanbedi M, Savari M, Kazi SN, Chew BT. Microwave-assisted synthesis of highly-crumpled, few-layered graphene and nitrogen-doped graphene for use as high-performance electrodes in capacitive deionization. Sci Rep. 2015;5:17503. https://doi.org/10.1038/srep17503.CrossRefGoogle Scholar
- 4.Amiri A, Shanbedi M, Ahmadi G, Eshghi H, Kazi SN, Chew BT, et al. Mass production of highly-porous graphene for high-performance supercapacitors. Sci Rep. 2016;6:32686. https://doi.org/10.1038/srep32686 https://www.nature.com/articles/srep32686#supplementary-information.
- 7.Shanbedi M, Amiri A, Zeinali Heris S, Eshghi H, Yarmand H. Effect of magnetic field on thermo-physical and hydrodynamic properties of different metals-decorated multi-walled carbon nanotubes-based water coolants in a closed conduit. J Therm Anal Calorim. 2017. https://doi.org/10.1007/s10973-017-6628-2.Google Scholar
- 29.Sarsam WS, Amiri A, Zubir MNM, Yarmand H, Kazi SN, Badarudin A. Stability and thermophysical properties of water-based nanofluids containing triethanolamine-treated graphene nanoplatelets with different specific surface areas. Colloids Surf A. 2016;500:17–31. https://doi.org/10.1016/j.colsurfa.2016.04.016.CrossRefGoogle Scholar
- 32.Amiri A, Shanbedi M, AliAkbarzade MJ. The specific heat capacity, effective thermal conductivity, density, and viscosity of coolants containing carboxylic acid functionalized multi-walled carbon nanotubes. J Dispers Sci Technol. 2016;37(7):949–55. https://doi.org/10.1080/01932691.2015.1074588.CrossRefGoogle Scholar
- 37.Hemmat Esfe M, Saedodin S. Turbulent forced convection heat transfer and thermophysical properties of Mgo–water nanofluid with consideration of different nanoparticles diameter, an empirical study. J Therm Anal Calorim. 2015;119(2):1205–13. https://doi.org/10.1007/s10973-014-4197-1.CrossRefGoogle Scholar
- 43.Yu W, Xie H, Chen L, Li Y, Li D, editors. The preparation and thermal conductivities enhacement of nanofluids containing graphene oxide nanosheets. 2010 14th International heat transfer conference; 2010: American Society of Mechanical Engineers.Google Scholar
- 56.Yang Y, Oztekin A, Neti S, Mohapatra S, editors. Characterization and convective heat transfer with nanofluids. ASME/JSME 2011 8th thermal engineering joint conference; 2011: American Society of Mechanical Engineers.Google Scholar