Microstructures in All-Inkjet-Printed Textile Capacitors with Bilayer Interfaces of Polymer Dielectrics and Metal-Organic Decomposition Silver Electrodes.

Soft printed electronics exhibit unique structures and flexibilities suited for a plethora of wearable applications. However, forming scalable, reliable multilayered electronic devices with heterogeneous material interfaces on soft substrates, especially on porous and anisotropic structures, is highly challenging. In this study, we demonstrate an all-inkjet-printed textile capacitor using a multilayered structure of bilayer polymer dielectrics and particle-free metal-organic decomposition (MOD) silver electrodes. Understanding the inherent porous/anisotropic microstructure of textiles and their surface energy relationship was an important process step for successful planarization. The MOD silver ink formed a foundational conductive layer through the uniform encapsulation of individual fibers without blocking fiber interstices. Urethane-acrylate and poly(4-vinylphenol)-based bilayers were able to form a planarized dielectric layer on polyethylene terephthalate textiles. A unique chemical interaction at the interfaces of bilayer dielectrics performed a significant role in insulating porous textile substrates resulting in high chemical and mechanical durability. In this work, we demonstrate how textiles' unique microstructures and bilayer dielectric layer designs benefit reliability and scalability in the inkjet process as well as the use in wearable electronics with electromechanical performance.