Development of Biocompatible Coatings on Flexible Electronics

This paper discusses silicone-coated flexible substrates to provide biocompatibility for implantable devices. In particular, we highlight recent developments on silicone coatings on high density, miniaturized polyimide-based flexible electronics. A variety of high density circuits ranging from 11 microns lines/space to 25 microns lines/spaces were processed on polyimide flex substrates and subsequently coated with biocompatible silicone coatings. The electrical performance of silicone coated batteries was characterized by voltage measurements. The final structure enhances the stretching capability. Biocompatible coatings were characterized by optical microscope to ascertain coating thickness and surface characteristics. An Impedance Analyzer was used for electrical characterization. Silicone coated batteryies are stable after water, acid and base treatments. Voltage change was insignificant even after dipping 75% of the coated battery (i.e., excluding the exposed terminals) in strong KOH (pH:13) solutions for over 60 days. The paper also describes a novel approach for the fabrication of silicone coated, flexible wearable miniaturized electronics for possible clothing applications.