Environment-Friendly Route for Stable Aqueous Dispersion of Reduced Graphene Oxide for Heat Transfer Application

Abstract

A simultaneous functionalization and reduction route to prepare stable dispersion of reduced graphene oxide from graphene oxide has been described. Diethanol amine has been introduced for the first time as an environment friendly reducing agent in a simple reflux reaction. Diethanol amine acts as a reducing agent and helps to enhance the stability of dispersion, making hydrogen bonding by virtue of two functional groups. The prepared dispersion of 0.025 mg/mL concentration is stable for months together and has a zeta potential value -45 V at room temperature. UV-Vis study shows peak at 264 nm that is signatory for reduced graphene oxide. TEM images confirm spread thin sheets of graphene of few hundred nanometer lateral dimension. Thermal diffusivity studies suggest nearly 60% enhancement for the dispersion in comparison to base fluid, water. This suggests graphene dispersion is promising for heat transfer applications.

Hybrid rGO-AgNPs Conductive Ink for Inkjet Printed Flexible Humidity Sensor

“…The other two signature peaks at 1180 cm -1 and 1030 cm -1 corresponds to epoxy C-O stretching and alkoxy C-O stretching, respectively. This data is in good correlation to the results obtained by Ota et al, [8].…”

“…The peak at 1677 cm −1 however showed a strong band in the rGO spectrum signifying the presence of aromatic C=C stretching possibly from the parental graphitic skeleton [9]. Two new peaks appearing at 2846 cm -1 and 2930 cm -1 were due to the stretching vibration of the -CH2 group in the alkyl chain [8]. Consequently, results obtained validated that the reduction of GO to rGO in rGO/AgNPs colloid has been successfully achieved.…”

Graphene dispersion in hydrocarbon medium and its application in lubricant technology

“…[30][31][32] This can be explained on the basis of difficulty in measuring the single layers of graphene by conventional methods such as thermal bridge, 3ω method or laser flash method. Hence, most of the reports are either theoretically proposed or by Raman optothermal and electrical measurements.…”

“…In spite of a fairly good understanding of the theoretical aspects of the thermal conductivity of graphene, only a small amount of experimental data has been reported to date. [30][31][32] This can be explained on the basis of the difficulty of measuring the single layers of graphene by conventional methods such as thermal bridge, the 3u method or the laser ash method. Hence, most of the reports are either theoretically proposed or rely on Raman optothermal and electrical measurements.…”