Abstract
Enhancement of thermal conductivity along the out-of-plane direction in polyimide（PI）blend films containing silver nanoparticles（Ag-NP）, µm-sized pyramidal or needle-shaped ZnO, and cubed MgO particles has been extensively investigated. Microphase-separated structures with "vertical double percolation（VDP）" morphology were spontaneously formed in the PI blend films composed of sulfur- and fluorine-containing PIs, in which two phases were separately aligned along the out-of-plane direction, and ZnO and MgO particles were preferentially precipitated in the fluorine-containing PI phase. In particular, the PI blend films containing needle-shaped ZnO particles exhibited significant enhancement of thermal diffusivity along the out-of-plane direction even at lower filler contents, which indicate that the VDP structure with selective incorporation of anisotropic shaped inorganic particles functions as highly efficient thermal conductive pathway.
