▎ 摘　　要

NOVELTY - A sandwich type graphene oxide/polyimide porous composite film comprises layer of fluorine-free polyimide flat film (A) and graphene oxide/fluorine-containing polyimide porous films attached to upper surface and lower surface of the layer of film (A). The pores in the porous film are distributed in multilayer mode. The pores in upper layer are uniform in size, and have average pore diameter of about 1.33-3.04 µm. The pores are arranged orderly and present a honeycomb-like structure. The pores in the lower layer are different in size and are arranged disorderly. USE - Sandwich type graphene oxide/polyimide porous composite film used as encapsulation material in fifth generation and microelectronics application in high humidity environment (all claimed). ADVANTAGE - The sandwich type graphene oxide/polyimide porous composite film has low dielectric, excellent water resistance and high mechanical performance. The method is simple, economical, and environmentally-friendly. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for preparation of sandwich type graphene oxide/polyimide porous composite film, which involves dissolving amphiphilic substance in organic solvent to prepare organic solution containing amphiphilic substance (A), dispersing graphene oxide in deionized water to prepare graphene oxide aqueous solution (B), mixing substance (A) with solution (B), stirring to prepare compound, dissolving compound and fluorine-containing polyimide in organic solvent to prepare pouring liquid, pouring liquid on upper surface and lower surface of the fluorine-free polyimide flat film under high humidity, pouring the liquid on one surface of the flat film, leaving for about 1.5 minutes, turning over the flat film, pouring the pouring liquid on the other surface, and leaving for about 1.5 minutes.