Multiscale Investigation of Interfacial Thermal Properties of n-Octadecane Enhanced with Multilayer Graphene
S Hajilar and B Shafei, JOURNAL OF PHYSICAL CHEMISTRY C, 123, 23297-23305 (2019).
Among various phase change materials that can be employed for energy- storage purposes, octadecane has received growing attention due to its chemical stability paired with nontoxic/noncorrosive characteristics. Octadecane, however, has a low thermal conductivity, which prevents it from efficient heat exchange with the surrounding environment. To address this issue, the promise of adding carbon-based nanofillers, including single and multilayer graphene (MLG), is investigated in this study from a fundamental perspective. For this purpose, the reverse nonequilibrium molecular dynamics method is employed according to the Muller-Plathe algorithm to understand the mechanisms governing thermal conductance at the interface of the octadecane matrix and graphene fillers. Based on rigorous vibration power spectrum analyses, it is revealed that interfacial thermal resistance increases by increasing the number of graphene layers. To scale up the findings of atomistic simulations and determine the macroscale thermal conductivity of octadecane-MLG composites, the effective medium theory is employed. The influence of MLG filler's length and volume fraction on the composite's thermal conductivity is investigated in detail. The outcome of this study provides the insight necessary to enhance the thermal transport properties of octadecane (and other similar paraffinic materials) for efficient energy-storage systems.
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