▎ 摘　　要

NOVELTY - Preparing a transparent gas barrier composite film comprises: providing a polyvinyl alcohol containing aqueous solution; providing a graphene oxide dispersed aqueous solution; blending polyvinyl alcohol containing aqueous solution with graphene oxide dispersed aqueous solution to obtain a casting solution; crosslinking by adding a crosslinking agent into the casting solution to have in-situ crosslinking reaction; and film-casting procedure to coat the casting solution after the in-situ crosslinking reaction on a substrate to form a coating and dry the coating to obtain a composite film. USE - The method is useful for preparing a transparent gas barrier composite film (claimed) that is used for flexible electronic devices. ADVANTAGE - The method: prepares composite film having a transmittance of more than 85%, oxygen transmission rate of less than 0.005 cc/m2/day and high gas barrier; reduces energy consumption; increases uniformity of a large-area composite film; and is simple and low cost. DETAILED DESCRIPTION - Preparing a transparent gas barrier composite film comprises: providing a polyvinyl alcohol containing aqueous solution; providing a graphene oxide dispersed aqueous solution; blending polyvinyl alcohol containing aqueous solution with the graphene oxide dispersed aqueous solution to obtain a casting solution where a weight ratio of graphene oxide in the graphene oxide dispersed aqueous solution to polyvinyl alcohol in the polyvinyl alcohol containing aqueous solution is less than 0.1 wt.%; crosslinking by adding a crosslinking agent into the casting solution to have in-situ crosslinking reaction; and film-casting procedure to coat the casting solution after the in-situ crosslinking reaction on a substrate to form a coating and dry the coating to obtain a composite film. An INDEPENDENT CLAIM is also included for a transparent gas barrier composite film, being formed by having polyvinyl alcohol, graphene oxide and a crosslinking agent undergo blending, crosslinking, film casting and isothermal crystallization where graphene oxide induces crystallization of polyvinyl alcohol to form a hybrid structure compose of polyvinyl alcohol crystals, graphene oxide and the crosslinking agent, crystallinity of polyvinyl alcohol is more than 30%, and transmittance of the composite film is more than 85%.