Large-Scale Fabrication of High-Performance Ionic Polymer–MetalComposite Flexible Sensors by in Situ Plasma Etching and MagnetronSputtering

摘要

Flexible electronics has received widespread concern and research. As a most-fundamental step and component, polymer metallization to introduce conductive electrode is crucial in successful establishment and application of flexible and stretchable electronic system. Ionic polymer–metal composite (IPMC) is such an attractive flexible mechanical sensor with significant advantages of passive and space-discriminative capability. Generally, the IPMC sensor is fabricated by the electroless plating method to form structure of ionic polymer membrane sandwiched with two metallic electrodes. In order to obtain high-quality interface adhesion and conductivity between polymer and metal, the plating process for IPMC sensor is usually time-consuming and uncontrollable and has low reproducibility, which make it difficult to use in practice and in large-scale. Here, a manufacturable method and equipment with short processing time and high reproducibility for fabricating IPMC sensors by in situ plasma etching and magnetron sputtering depositing on flexible substrates is developed. First, the new method shortens the fabrication periodgreatly from 2 weeks to 2 h to obtain IPMC sensors with sizes up to9 cm × 9 cm or arrays in various patterns. Second, the integratedoperation ensures all sample batch stability and performance repeatability.In a typical IPMC sensor, nearly 200 mV potential signal due to ionredistribution induced by bending strain under 1.6% can be producedwithout any external power supply, which is much higher than the traditionalelectroless plating sensor. This work verified that the in situ plasmaetching and magnetron sputtering deposition could significantly increasethe interface and surface conductivity of the flexible devices, resultingin the present high sensitivity as well as linear correlation withstrain of the IPMC sensor. Therefore, this introduced method is scalableand believed to be used to metalize flexible substrates with differentmetals, providing a new route to large-scale fabrication of flexibledevices for potential wearable applications in real-time monitoringhuman motion and human–machine interaction.