Preparation of high temperature resistant Ag/PI/Cu composite nano particles inserted with PI insulating layer

Polyimide (PI)@copper (Cu) composite nano particles have been successfully synthesized from poly(amic acid) triethylamine salts (PAAS) and Cu(II) ions via a one-step high-temperature induction/imidization route. The formation of PI@Cu nano particles has been investigated by the stoichiometric ratio of PAAS and Cu ion. The resulting products, formed stable shell-core structures, exhibited the uniform core-size and thick shell layer. Additionally, the multi-layer structure, Ag@PI@Cu, was successfully prepared via a post process of PI@Cu nanoparticles. The morphology of the formed “Sunflower-mode” structure, with the pistil of Cu, the sunflower seed of PI, and the petal of Ag, was also characterized by SEM and TEM. Both electrical resistivity and thermal conductivity of nano particles were measured. The coefficient of heat conduction of Ag@PI@Cu is even 255 times, 754 times, 3081 times, and 1310 times as large as PI@Cu in 50 °C, 100 °C, 150 °C, and 200 °C, respectively. The resistance of both nano particles is that the result of Rs_PI@Cu and Rs_Ag@PI@Cu is 11.0*10⁹ Ω and 0.11 Ω, respectively, and also the difference between them is more than 10¹².