Transparent, Flexible, and Stable Polyethersulfone/Copper‐Nanowires/Polyethylene Terephthalate Sandwich‐Structured Films for High‐Performance Electromagnetic Interference Shielding

Abstract

Transparent and flexible electromagnetic interference (EMI) shielding materials are highly desirable in wearable electronic devices and optical windows of aircrafts. Herein, transparent and flexible EMI shielding films are prepared by the use of Cu nanowires (Cu NWs). The films have a sandwiched structure composed of polyethersulfone (PES), Cu NW network, and polyethylene terephthalate (PET). The coating of PES strengthens the Cu NW contact, protects Cu NWs from the oxidation, and reduces the surface average roughness. The PES/Cu NWs/PET sandwich‐structured films show an EMI shielding effectiveness (SE) of 22 dB with an optical transmittance of 73%, and an even higher EMI SE of 30 dB in the entire X band with the optical transmittance of 67%. The PES/Cu NWs/PET sandwich‐structured films also exhibit superior flexibility, very good chemical stability in basic, acidic, and strong oxidizing solutions, as well as long‐term stability in ambient condition. This PES/Cu NWs/PET sandwich‐structured films are a promising transparent flexible EMI shielding material in wearable electronics and optical windows of aircrafts.