Effects of Spatial Configuration and Chain Connection of Nanodiamond Fillers on the Enhancement of Thermal Conductivity of Epoxy Composite

Abstract

Creating an efficient thermal conductivity network is crucial to improve the thermal conductivity (TC) of epoxy resin (EP)-based nanocomposites. In this work, the effects of different spatial configurations including particle spacing, inclination angle and chain connections of nanodiamond fillers on the TC of EP-based composites were quantificationally explored using molecular dynamics simulations. The results reveal a parabolic reduction in the composite TC as the center-to-center distance of the particle pair increases due to the attenuated particle interactions. When gradually increasing the inclination angle of the center-to-center line of the particle pair relative to the heat flux direction, the composite TC initially decreases sharply followed by a convergence trend. Additionally, when a single EP chain is covalently bonded to the nanoparticle pair, the TC decreases to a certain point but subsequently rebounds and exceeds the initial value as the particle spacing increases. This rebound indicates the effective thermal conductive pathway formed by the EP chain begins to play a dominant role in the thermal conduction of nanocomposites compared to particle interactions. This was also firmly validated by analyzing the order parameter distribution and temperature distribution. Furthermore, an enhanced TC can also be obtained by applying torsion to the particle pair connected with double EP chains. This work attempts to provide a comprehensive understanding of constructing efficient thermal conductivity networks and offers valuable insights for the design of high-performance thermal interface materials.

Keywords: Epoxy resin-based nanocomposites, Molecular dynamics, Spatial configuration, Thermal Conductivity