Enhancing thermal conductivity in epoxy composites: insights from nanodiamond filler spatial configuration and chain linking

Creating an efficient thermal conductivity network is crucial to improve the thermal conductivity (TC) of epoxy resin (EP) – based nanocomposites. This study systematically investigates the intricate relationship between the spatial configurations of nanodiamond fillers – including particle spacing, inclination angle, and chain connectivity – and the TC of epoxy-based composites by using molecular dynamics simulations. The results reveal a parabolic TC reduction as interparticle distance increases due to attenuated interactions. When increasing the inclination angle of the center-to-center line of the particle pair relative to the heat flux direction, the 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. Furthermore, an enhanced TC can also be obtained by applying torsion to the particle pair connected with double EP chains. This work provides a comprehensive understanding of constructing efficient thermal conductivity networks and offers valuable insights for the design of high-performance thermal interface materials.