薄膜面内微结构对热物性的调控研究

A method of fabricating in-plane microstructures to control the in-plane thermal conductivity and the surface infrared emissivity of the polyimide film was proposed. By establishing a simplified two-dimensional heat transfer model, the equivalent in-plane thermal conductivity of a periodic microstructured film was calculated. The effects of the contact area ratio and the filling factor of the microstructures on the equivalent thermal conductivity and the equivalent infrared emissivity were studied. Theoretical calculations show that when the contact area ratio was 0.18 and the fill factor was 0.28, the equivalent in-plane thermal conductivity of the polyimide film was decreased to 18.8% compared to that of the material itself. Two polyimide film samples with different contact area ratios and fill factors were fabricated. The diameter and the thickness of both films were 65mm and 500nm, respectively. The in-plane thermal conductivity of the pure polyimide film measured by a non-contacted in-plane thermal conductivity measurement was 0.164W/mK, and the in-plane thermal conductivities of the microstructured polyimide film with contact area ratio of 0.20 and 0.46 were 0.041W/mK and 0.091W/mK, and the emissivity were 0.161 and 0.175, respectively.