▎ 摘　　要

NOVELTY - Preparation of graphene heat-conducting film includes using improved Hummers method to prepare graphene oxide powder as precursor from expanded graphite, dissolving the prepared graphene oxide powder in water, ultrasonically processing and dispersing uniformly to obtain uniform and stable graphene oxide dispersion liquid; putting the silicon substrate in a mixed solution of concentrated sulfuric acid and hydrogen peroxide solution, heating in water bath, washing with a large amount of deionized water, and placing in a vacuum drying box for drying; and soaking polyethylenimine (PEI) water solution on the silicon substrate for 1 minute, spin coating the silicon substrate at 800 revolutions/minute (rpm) for 1 minute by a spin coater, dispersing the solution uniformly, spin coating the silicon substrate at 1000 rpm for 1 minute so that the formed film becomes thin, and spin coating the silicon substrate at 2000 rpm for 1 minute to dry the film. USE - The method is for preparation of graphene heat-conducting film. ADVANTAGE - The method reduces the gap between the graphene film layers, improves the thermal conductivity, prepares the graphene heat conducting film with stable quality, excellent radiating effect, and high flexibility, has simple process steps, low cost, controllable thickness, simple operation, and high production efficiency, and is suitable for industrial production. DETAILED DESCRIPTION - Preparation of graphene heat-conducting film comprises using improved Hummers method to prepare graphene oxide powder as precursor from expanded graphite, dissolving the prepared graphene oxide powder in water, ultrasonically processing and dispersing uniformly to obtain uniform and stable graphene oxide dispersion liquid, where ultrasonic time is 1 hours; putting the silicon substrate in a mixed solution of concentrated sulfuric acid and hydrogen peroxide solution, heating in water bath, washing with a large amount of deionized water, and placing in a vacuum drying box for drying; soaking polyethylenimine (PEI) water solution on the silicon substrate for 1 minute, spin coating the silicon substrate at 800 revolutions/minute (rpm) for 1 minute by a spin coater, dispersing the solution uniformly, spin coating the silicon substrate at 1000 rpm for 1 minute so that the formed film becomes thin, and spin coating the silicon substrate at 2000 rpm for 1 minute to dry the film; putting the silicon substrate in a smooth glass container, slowly dropping the graphene oxide dispersion liquid into the glass container and ensuring the solution to completely immerse the silicon substrate; putting the glass container in a constant temperature water bath, and forming flat graphene oxide (GO) film on the silicon substrate by using gas-liquid interface self-assembly technique; putting the prepared GO film into a vacuum drying box to dry for 2 hours at 80 degrees C to obtain the dried GO film; taking off the obtained dried GO film, putting into a tubular furnace, carrying out carbonization treatment, and naturally cooling; putting the reduced graphene oxide (rGO) film into a graphitizing furnace, performing graphitization atomic recombination process, and naturally cooling to room temperature to obtain the graphene heat conducting film semi-finished product; and rolling.