▎ 摘　　要

NOVELTY - Preparing multilayer porous electromagnetic shielding composite foam material with adjustable heterogeneous structure comprises (1) modifying polydopamine on the surface of the sponge skeleton with an open-pore structure to obtain a polydopamine-modified sponge, (2) heating the paraffin to make it melt completely, (3) carrying out electroless silver plating to the sponge coated with paraffin wax to the part thickness of step (2) gained, (4) adding carbon nanofillers and aqueous polyurethane to deionized water, and (5) filling the suspension obtained in the step (4) in the heterogeneous composite sponge with layered deposition of silver nanoparticles obtained in the step (3), and then freeze-drying to obtain multilayer porous electromagnetic shielding composite foam material with adjustable heterogeneous structure. USE - The method is useful for preparing multilayer porous electromagnetic shielding composite foam material with adjustable heterogeneous structure, which is used in communication technology and electronic device, mobile phone, personal digital assistant (PDA), portable multimedia player (PMP), digital camera, digital video camera (DVC), digital photo frame, portable game machine and portable electronic book (e-book). ADVANTAGE - The structure of the multilayer composite foam prepared by the method is controllable, and a heterogeneous structure electromagnetic shielding material with high electromagnetic shielding performance can be prepared through a simple method. DETAILED DESCRIPTION - Preparing multilayer porous electromagnetic shielding composite foam material with adjustable heterogeneous structure comprises (1) modifying polydopamine on the surface of the sponge skeleton with an open-pore structure to obtain a polydopamine-modified sponge, (2) heating the paraffin to make it melt completely, using the melted paraffin, dipping the polydopamine-modified sponge obtained in the step (1) to cover part of the thickness of the sponge, then cooling to solidify the paraffin, and obtaining a sponge partially covered by paraffin, (3) carrying out electroless silver plating to the sponge coated with paraffin wax to the part thickness of step (2) gained, making the in-situ deposition of silver nanoparticles on the surface of the sponge skeleton that is not coated with paraffin wax, and removing the paraffin to obtain a heterogeneous composite sponge with layered deposition of silver nanoparticles, (4) adding carbon nanofillers and aqueous polyurethane to deionized water, fully stirring, and dispersing under the ultrasonic action of a cell crusher to form a uniform and stable suspension, and (5) filling the suspension obtained in the step (4) in the heterogeneous composite sponge with layered deposition of silver nanoparticles obtained in the step (3), and then freeze-drying to obtain multilayer porous electromagnetic shielding composite foam material with adjustable heterogeneous structure.