▎ 摘　　要

NOVELTY - Hydrogel is prepared by crosslinking mixture of polyamic acid and graphene oxide with cobalt salt. USE - As hydrogel. ADVANTAGE - The hydrogel is synthesized by simple process, simple to operate and environmentally-friendly, and has excellent crosslinking strength. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing the hydrogel, comprising (a) dissolving aqueous-soluble polyamide acid in graphene oxide aqueous solution, and uniformly stirring to obtain graphene oxide/polyamide acid hydrogel solution, (b) adding cobalt salt solution to the graphene oxide/polyamide acid hydrogel solution and uniformly stirring to obtain cobalt crosslinked hydrogel, where the mass ratio of cobalt salt and aqueous-soluble polyamide acid is 0-0.3, and the mass ratio is not 0.