▎ 摘　　要

NOVELTY - Preparing graphite thin foam/polydimethylsiloxane composite material having an adjustable negative dielectric constant involves adding graphite oxide to water to prepare a solution, adjusting the pH value of the solution, and performing dispersion treatment. The graphene solution is subjected to high temperature treatment, and graphene hydrogel is taken out after cooling, and freeze-dried to obtain graphene foam. The high-temperature reduction treatment of graphene foam is performed under nitrogen protection. Polydimethylsiloxane, curing agent and n-hexane are mixed to obtain a polydimethylsiloxane impregnating solution for immersion. The high-temperature reducing graphene foam is cut into a pieces and immersed in a polydimethylsiloxane impregnating solution. It is further cured under vacuum conditions to obtain graphene thin foam/polydimethylsiloxane composite material. USE - Method for preparing graphite thin foam/polydimethylsiloxane composite material. ADVANTAGE - The method involves subjecting the graphene foam obtained after freeze-drying to high-temperature reduction to have good electrical conductivity, and is combined with polydimethylsiloxane to obtain a composite material with good mechanical properties. The obtained product has a negative dielectric constant and a magnetic permeability ranging from 1 megaHertz to 1 gigaHertz, and the composite material is deformed to different degrees by applying different pressures. The regulation of its dielectric constant is beneficial in wider application of polymer composites in the double negative properties of metamaterials, which brings new opportunities for the design and development of new materials.