Role of Filler-Polymer Interface on the Thermal Conductivity in Polymer Composites

Polymers with high thermal conductivity are the need of modern technologies due to their robustness, cost-effective, and less corrosiveness. However, bare polymers are not good heat-conductors due to their molecular structures, and their non-metallic properties. Therefore, metallic fillers of different shape and size have been used to enhance the thermal conductivity in polymer-composites. However, there has been search of best geometrical fillers which can maximize the thermal conductivity effectively with same volume percent. From our numerical simulations, we show that the best geometrical fillers are those which have high surface-area (S) to volume (V) ratio. In such cases the interface of polymer-filler is maximized, which leads to the effective enhancement in the thermal conductivity. To validate our claim we use fillers with same volume percent but maximize the surface area. We also show that there is a competition between surface and the bulk of the filler in this maximization process but surface-area dominates with an effective increase in the thermal conductivity. We use 3-dimensional models using ANSYS-Fluent to show the characteristic behavior of thermal conductivity. Polyethylene has been used as the base polymer and aluminum (Al) has been used as filler in all our model simulation.