Ink-Coated Silver Films on PET for Flexible, High Performance Electromagnetic Interference Shielding and Joule Heating

There is a need for high efficiency electromagnetic interference (EMI) shielding and highly efficient joule heating materials that may be incorporated into flexible substrates. In this work, we demonstrate silver films on polyethylene terephthalate (PET) with a low sheet resistance of 57 mohm/sq, high EMI shielding efficiency of 82.6 dB in the X band (8–12 GHz) and 85.3 dB in the Ku band (12–18 GHz), and high Joule heating performance with a stable temperature of 147.0 °C at only 1.5 V DC power input. The silver films are fabricated using a reactive particle free silver ink, which is cured at only 100 °C, and polyurethane diol (PUD) is utilized to enhance adhesion to PET. The PUD enables excellent mechanical flexibility, where the EMI shielding efficiency does not degrade after 10 000 times bending at a 0.4 cm bending radius. This work achieves high EMI SE with small film thickness of only 11.7 μm and stable high temperatures at low applied voltage, both of which have been difficult to achieve. This work demonstrates coated silver thin films on PET as a a flexible material for efficient EMI shielding protection and Joule heating that may be used for smart wearable devices, personal medical electronics, and next generation communications.