▎ 摘　　要

NOVELTY - Preparing the polyimide film with directional heat dissipation function comprises (i) preparing polyamic acid solution; (ii) adding inorganic heat-conducting powder into the polyamic acid solution and stirring evenly to obtain a mixture, scrape-coating the mixture on the glass substrate, and performing high-temperature pre-imidization treatment to form a heat-conducting layer on the glass substrate; (iii) scraping another polyamic acid solution and coating on the heat conducting layer to form a polyamic acid scraped coating, and soaking in a phase separation solvent, forming a porous structure on the surface of the polyamic acid scratch coating, performing high-temperature imidization treatment, forming imidization double-layer film with porous structure on the glass substrate; and (iv) filling the phase change material into the porous structure of the imidized bilayer membrane. USE - The polyimide film is used in flexible substrates or thermal management materials for flexible electronics and wear-resistant. ADVANTAGE - The method prevents the heat of the heat conduction layer from penetrating in the vertical direction through the phase change process; provides high-strength mechanical support; the polyimide film has a high thermal conductivity on one side and has good heat storage capacity on the other side, keeps the polyimide characteristics with high strength, prevents the penetration of heat in the vertical direction; has high strength, high elongation at break and directional radiating function; improves the device radiating passage, and improves human body sensing comfort level. DETAILED DESCRIPTION - Preparing the polyimide film with directional heat dissipation function comprises (i) preparing polyamic acid solution; (ii) adding inorganic heat-conducting powder into the polyamic acid solution and stirring evenly to obtain a mixture, where the mass of the inorganic heat-conducting powder accounts for 10-50% of the total mass of the polyamic acid in the inorganic heat-conducting powder and the polyamic acid solution, scrape-coating the mixture on the glass substrate with a thickness of 5-500 µm, and performing high-temperature pre-imidization treatment to form a heat-conducting layer on the glass substrate; (iii) scraping another polyamic acid solution and coating on the heat conducting layer to form a polyamic acid scraped coating with a thickness of 60-550 μm, and soaking in a phase separation solvent at 0-65℃, forming a porous structure on the surface of the polyamic acid scratch coating and within a thickness range of 50-500 μm from the surface, where the thickness of the non-porous structure in the polyamic acid scraping coating is 10-50 µm, taking out, performing high-temperature imidization treatment, forming imidization double-layer film with porous structure on the glass substrate; and (iv) filling the phase change material into the porous structure of the imidized bilayer membrane. An INDEPENDENT CLAIM is also included for the polyimide film with directional heat dissipation function prepared by above method.