Tailoring the dielectric properties and thermal conductivity of f-Cu/PVDF composites with SiO2 shell as an interfacial layer

To prominently suppress the dielectric loss of flaky-Cu (f-Cu)/poly(vinylidene fluoride) (PVDF) while still holding a high permittivity (k), silica (SiO2) encapsulated f-Cu core-shell structured particles were prepared through a sol-gel method, and the f-Cu@SiO2 were incorporated into PVDF to expect a high-k but low loss composites. The dielectric properties and thermal conductivity (TC) of the composite were explored in terms of the SiO2 shell. The results manifest that the f-Cu@SiO2 remarkably decreases the dielectric loss and conductivity of the composites thanks to the presence of SiO2 interlayer preventing the pristine f-Cu from direct contact. The thickness of SiO2 interlayer should be finely tuned to exert the optimal influence on dielectric properties and TC of composites. Furthermore, the dielectric properties and TC of the composites were thoroughly investigated as a function of the weight ratio of SiO2 to f-Cu, catalyst loading and reacting temperature. When the weight ratio, catalyst loading and reacting temperature values are set as 1:(0.1-0.15), 1.0 vol.%, and 50 degrees C, respectively, the best dielectric properties and enhanced TC can be reached. The prepared Cu@SiO2/PVDF composites with a high-k but low loss, as well as enhanced TC, show more promising applications for microelectronic and electrical industry.