A Novel Flexible Silver Heater Fabricated by a Solution-Based Polyimide Metalization and Inkjet-Printed Carbon Masking Technique

An easy-to-fabricate, high-performance, and ultrabendable heater is always essential for the development of flexible devices such as gas sensors. Currently, most of the flexible heaters involve vacuum facilities or special inkjet printers/inks, which leads to complex processes and high fabrication cost. In this work, an innovative polymeric metalization technique was developed on polyimide substrate: in addition to the tunable electrical properties, Ag thin films obtained through the low-temperature solution-based process, the so-called surface modification and ion exchange (SMIE) process, could provide enhanced interfacial adhesion and mechanical stability. With a carbon ink as a masking layer, generated by a common home-/office-use inkjet printer, more than 400 patterned flexible heaters can be batch-fabricated on an A4 size polyimide conveniently. The results indicate that the heaters exhibit good electrical properties as well as superior bending stabilities. For the heaters with dimension of 1 cm × 1 cm, under an applied voltage of 20 V_dc, the maximum temperature achieved is 300 °C. Both the response time and recovery time are less than 15 s. The heaters can bear more than 1200 times bending cycling with a relative resistance change ratio of 0.11%. The developed technology is compatible with current batch fabrication processes such as roll-to-roll and can be employed to develop flexible heaters with high mechanical stability in the future.