(ES2383356-A1)   NOVELTY - The method involves preparation an aqueous solution of a water soluble biopolymer to form a non-crystallizing hydrogels or a derivative of biopolymer. The biopolymer is thermally decomposed on a substrate at 1200 degrees C in absence of oxygen. The substrate coated with aqueous solution of biopolymer is conducted by immersing substrate in the solution or by using spin coating technique.    USE - Method for preparing graphene film or graphene materials for use in microelectronics and photovoltaic industries.    ADVANTAGE - The method involves preparation an aqueous solution of a water soluble biopolymer to form a non-crystallizing hydrogels or a derivative of biopolymer, and thus prepares graphene film or graphene materials in a simple and cost-effective manner with enhanced conductive properties, such as transparency and flexibility.    DETAILED DESCRIPTION - Preparation of graphene films or graphene materials nonmetallic substrates comprises: preparing an aqueous solution of a non-crystallizable biopolymer or a derivative of the biopolymer at a suitable pH; coating the substrate with the prepared aqueous biopolymer solution; conditioning the aqueous biopolymer solution by a hydrothermal process consisting in subjecting the coated surface to a flow of nitrogen or argon saturated with water vapor at 100-250 degrees C for 30 minutes and a number of hours; and thermal decomposition of the biopolymer deposited on the substrate in the absence of oxygen at temperatures below 1200 degrees C. An INDEPENDENT CLAIM is graphene substrate prepared by the method above, comprising a layer of non-metallic substrate selected from the group comprising quartz, glass, ceramics, ceramic paste, and plastic, and one or more graphene layers with a resistance of 500-10000 Ohms/square.    DESCRIPTION OF DRAWING(S) - The drawing shows a graphical representation depicting thickness of the graphene layer. (Drawing includes non-English language text).    Different distances (X)    Thickness (Z)