Flex to Stretch Electronics

Effective Mechanical and Electrical Bonding of Stretch-to-Flex Electronics

Kunal Mondal¹, Steven Erlenbach¹, Siyuan Ma², Andrew Fassler², Jim Holbery², Michael D. Dickey¹

1Department of Chemical and Biomolecular Engineering, North Carolina State University

Engineering Bldg 1

911 Partners Way

Raleigh, NC 27606

2 Applied Science Group, Microsoft Corporation

Redmond, WA

Abstract

Stretchable electronic devices maintain electrical connections when subjected to stress or strain and are therefore useful for enabling electronics with new mechanical properties. However, these devices often require power or electrical signals from non-stretchable components. Connecting flexible and stretchable substrates is a possible solution that maintains the electrical connection within a medium that can withstand deformation and prolonged use. The ability to create a robust electrical connection between these mechanically disparate components may enable new types of hybrid devices. In this study we present a basic method to adhere and thereby fabricate such new hybrid devices. The adhesion at the interface arises from surface chemistry that forms strong, covalent bonds. The utilization of liquid metals as the conductor provides stretchable interconnects because liquid metals are both conductive and fluidic. We characterized the mechanical and electrical properties of these hybrid devices. While we focus on silicone elastomers and liquid metals, there are numerous other methods of fabricating stretchable devices that share many properties with the devices in this work.