Thermal properties of graphene/stearic acid composite based on molecular dynamics

Abstract

To investigate the methods and mechanisms for enhancing the thermophysical properties of SA-based PCM, this study employed molecular dynamics simulation to systematically explore the effects of GE mass fraction (0.5 wt.%, 5 wt.%, 10 wt.%) and layer number (single-layer/double-layer) on the thermophysical properties and microstructure of SA/GE composite PCM within the temperature range of 300 K to 390 K. Through simulations and calculations of the thermal conductivity, radial distribution function, end-to-end distance, interaction energy, and phonon density of states of the composite system, it was found that the addition of GE significantly increased the thermal conductivity of the composite material, with the highest enhancement of 42.3 % compared to the pure SA system, and the enhancement effect of single-layer GE was superior to that of double-layer GE. GE not only provided thermal conduction paths by virtue of its high intrinsic thermal conductivity but also induced the ordered arrangement of SA molecules, increased the end-to-end distance, reduced the molecular diffusion ability, and increased the number of low-frequency phonons, thereby enhancing the thermal transport performance. This study revealed the mechanism of GE enhancing the thermal conductivity of SA at the microscopic level, providing a theoretical basis for the design of high-performance composite PCM.