Thermal conductivity of nanocomposites with high volume fractions of particles

The model proposed by Ordonez-Miranda et al. [Appl Phys Lett 2001;98(233): 111], for the thermal conductivity of composites with low volume fractions of nanoparticles is extended for high volume fractions of spherical and cylindrical nanoparticles. In the dilute limit of macro/micro-sized particles, the obtained results agree with the ones previously reported. In contrast, when the radius of the particles is of the order of the mean free path of the energy carriers, it is shown that the dependence of the composite thermal conductivity on the collision cross-section per unit volume of the particles and the average distance that the energy carriers can travel inside the particles becomes stronger when the volume fractions of particles increases and is cancelled out for high enough interfacial thermal resistances. The predictions of the proposed analytical approach are in good agreement with reported experimental data and could be highly useful for guiding the design of particulate nanocomposites where the interactions among the particles and the interfacial scattering of the electrons and phonons need to be considered.