Molecular Dynamics Simulations of Self-Assembled Polyethylene-Hexagonal Boron Nitride Composite and Its Thermal Conductivity

The demand of the heat dissipating polymer-based composites is increasing because of the processibility, light weight, corrosion resistance, and low cost of polymers regardless of their low thermal conductivity. It is well known that 3-dimensional arrangement and the relative orientation of the filler particles with high thermal conductivity significantly influence the composite thermal conductivity. To study the relation between the composite internal structure and the thermal conductivity, we developed the atomistic model and measure the thermal conductivity of composites. The self-assembled structure of the composite composed of polyethylene (PE) matrix and hexagonal boron nitride (hBN) sheets is obtained at the atomistic level using annealing molecular dynamics simulations. We found that the hBN sheets prefer a stacked structure because of strong electrostatic interactions, and they form a segregated domain inside the polymer matrix. The effect of hBN concentration on the thermal conductivity is calculated and were found to be in good agreement with the experimental results.