Flexible and robust silver coated non-woven fabric reinforced waterborne polyurethane films for ultra-efficient electromagnetic shielding

The rapid popularity of portable and wearable smart electronics has put forward more stringent requirements for flexible electromagnetic interference (EMI) shielding films with excellent mechanical strength and EMI shielding effectiveness (SE). However, there are still many obstacles to simultaneously satisfy the above critical requirements and new strategy for designing high-performance EMI shielding films is needed. Herein, a flexible and highly-efficient EMI shielding waterborne polyurethane (WPU) composite film with excellent mechanical strength and shielding stability is prepared by the facile compounding with silver coated non-woven fabrics (Ag/NWF). The Ag/NWF/WPU composite film (10.5 wt% Ag) with a thickness of only 400 mu m possesses an outstanding EMI SE of 72.5 dB in the frequency range of 2-18 GHz, and the tensile strength can reach 12 MPa. The incorporation of FeCo alloy deposited on reduced graphene oxide (FeCo@rGO) nanoparticles further improves the EMI SE to 77.1 dB. Moreover, because of the robust mechanical properties of the composite film, a highly reliable shielding ability is also achieved with over 95% EMI SE retention after 1000 folding cycle tests. This flexible and robust WPU film with highly-efficient shielding performance is promising for the application in next-generated flexible electronic devices.