Comparative study of thermal conductivity in crystalline and amorphous nanocomposite

Abstract

Silicon nanocrystals (SiNCs)/polystyrene (PS) nanocomposite has been observed to have a significant decrease in thermal conductivity in terms of the SiNC fraction with unspecified factors remained unclear. In this paper, amorphous silicon nanoparticles (a-SiNPs) with a mean diameter of 6 nm and PS nanocomposites were synthesized, and their thermal conductivity, including the density and specific heat, was compared with our previous work which investigated well-crystalized SiNPs (6 nm) and PS nanocomposite. The difference between amorphous and crystalline structure is insignificant, but phonon scattering at SiNPs and PS boundary is the key influencing factor of thermal conductivity reduction. The effective thermal conductivity models for nanocomposite revealed that the thermal boundary resistance, explained by Kapitza principle, is estimated to be 4 × 10−7 m2K/W, showing the significant effect of nanostructured heterogenic surface resistance on overall heat transfer behavior. Preservation of unique properties nanoscale materials and low-cost fabrication by silicon inks process at room temperature give the promising potential of SiNPs based heat transfer management.