▎ 摘　　要

NOVELTY - Preparing graphene conductive film based on nano-soft printing technology, comprises mixing expandable graphite and potassium nitrate, adding concentrated sulfuric acid, stirring, adding potassium permanganate, reacting, diluting by adding deionized water, adding hydrogen peroxide, diluting the obtained bright yellow colored mixture, filtering to obtain the final filtrate, drying to obtain graphene oxide, adding a layer of graphene oxide suspension, vacuum drying to obtain graphene oxide on the film substrate, restoring modification by heating graphene oxide and cooling to obtain the product. USE - The method is useful for preparing graphene conductive film. ADVANTAGE - The method solves the problem of high cost and uncontrollable shape and size of the present conductive thin film technology and achieves nano-scale thickness of the graphene conductive film. DETAILED DESCRIPTION - Preparing graphene conductive film based on nano-soft printing technology, comprises: (a) preparing graphene oxide by (i) mixing expandable graphite (80-200 meshes) and potassium nitrate (in a mass ratio of (2-5):1) in a container, placing the container in an ice bath, stirring at a rate of 200-800 revolutions/minute, adding concentrated sulfuric acid (98.3 wt.%), reacting by stirring for 5-30 minutes at a rate of 200-800 revolutions/minute, adding potassium permanganate at the rate of 1 g/second to obtain a brown mixture, continuing to react for 0.5-4 hours by stirring at a rate of 200-800 revolutions/minute, (ii) removing the container from the ice bath, heating at 30-40 degrees C, maintaining the temperature, continuously stirring and reacting for 2-12 hours, heating to 80-100 degrees C for 10-50 minutes, diluting by adding deionized water, adding hydrogen peroxide (30 wt.%) until the mixture color changes from brown to bright yellow, (iii) diluting the obtained bright yellow colored mixture using de-ionized water, filtering, washing the obtained precipitate at 40-80 degrees C, washing repeatedly, filtering to obtain the final filtrate of pH between 6-7, washing the final precipitate, placing into a vacuum oven and drying at 40-80 degrees C for 12-36 hours to obtain the graphene oxide, where the mass ratio of: concentrated sulfuric acid (98.3%) to expandable graphite (80-200 meshes) is (35-175):1, potassium permanganate to expandable graphite (80-200 meshes) is (3-15):1, de-ionized water to expandable graphite (80-200 meshes) in step (ii) is (60-80):1, and de-ionized water to expandable graphite (80-200 meshes) in step (iii) is (100-300):1, (b) preparing graphene oxide film by preparing graphene oxide suspension (0001-0.005 g/ml), cleaning the film substrate, adding a layer of graphene oxide suspension (drop wise) by pressurizing the grooves of the polymer template at a pressure 0.3-0.7 N/cm2, placing in a vacuum oven, removing the groove of the polymer template, vacuum drying at 40-100 degrees C for 0.5-2 hours to obtain the graphene oxide on the film substrate, where the film substrate is silicon chip, glass sheet or poly(ethylene terephthalate) film, the groove of the polymer template is a strip groove, a square groove or a round groove, the polymer template with grove is poly(methyl methacrylate) template, polydimethylsilicoxane template, epoxy resin template, polyurethane template, polyimide template or phenolic resin template, the depth of the bar-shaped groove or square groove is 0.5-50 mu m and the width ratio of bar groove or square groove to the strip groove or square groove is (0.1-20):1, the depth of the round groove is 0.5-50 mu m and the ratio of depth to the diameter of the circular groove is (0.1-20):1, and (c) restoring modification by placing the prepared graphene oxide film substrate in a tubular furnace, vacuuming the tubular furnace at room temperature and filling with reducing gas and inert gas in a volume ratio of 1:(1-10), heating the furnace up to 500-1000 degrees C, maintaining the temperature and continuously heating for 10-60 minutes and cooling to room temperature to obtain the graphene conductive film, where the reducing gas is hydrogen or ammonia and the inert gas is argon, nitrogen or helium.