Effect of functionalization on adsorption and thermal property of graphene nanosheet/paraffin composite

Functionalization of graphene nanosheet (GNS) is found to be useful for improving the thermal property of materials. However, the mechanism responsible for the enhancement is still open. In this article, molecular dynamic simulation is adopted to investigate the effects of four functionalized groups, including -COOH, -NH2, -OH, and -CH3, on the adsorption and thermal properties of GNS/paraffin (PA) composites. The results show that it forms a spherical structure after GNS absorbs in PA. The loading rate of the systems follows the order: GNS-COOH/PA > GNS-NH2/PA > GNS-OH/PA > GNS-CH3/PA > GNS/PA, which is determined by the adsorption free energy. Due to the functionalization, the latent heats of the composites undergo a significant change and the thermal conductivities are significantly enhanced. GNS-OH/PA exhibits the most substantial improvement with the latent heat increasing by 11.2% and the thermal conductivity increasing by 107.4% compared to GNS/PA. The study demonstrates the potential of these composites for energy storage applications, highlighting the improved performance through functionalization.