Flexible Ag-Coated Carbon Nanofibers/Bacterial Cellulose Films for Electromagnetic Interface Shielding and Multifunctional Thermal Applications

Flexible electromagnetic interference (EMI) shielding materials are in urgent need in the flexible and wearable electronics fields. In this study, multifunctional flexible silver-coated carbon nanofibers/bacterial cellulose (Ag/CNFs/BC) films were fabricated by vacuum filtration equipment using bacterial cellulose as a flexible substrate. Silver-coated carbon nanofibers were prepared by the chemical deposition method, and the silver was uniformly coated on the surface of carbon nanofibers with scanning electron microscopy (SEM) observation. Compared with the carbon nanofibers/bacterial cellulose (CNFs/BC) films, the EMI performance of Ag/CNFs/BC films was greatly enhanced because of the improvement of conductivity up to 4184 S/m. The EMI shielding effectiveness was highly enhanced over 55 dB in the X-band (8–12 GHz) under a relatively low thickness of 34 μm for the Ag/CNFs60/BC film. Moreover, the Ag/CNFs60/BC film also showed great multifunctional thermal applications. A Joule heating of over 110 °C at 3 V direct current and a photothermal conversion over 60 °C under an optical power density of 100 mW/cm2 were achieved. These results indicated that the Ag/CNFs/BC films with nanomaterials have huge application potential as flexible wearable self-heating products with excellent electromagnetic shielding performances.