Magnetically Aligned Liquid Metal Anisotropic Conductive Films for Use in Stretchable Integrated Circuits

Soft, elastically deformable, and highly-functional electronics are critical components for emerging applications in wearable computing, soft robotics, and human–machine interaction that demand mechanical compliance. Hybrid circuits that combine soft and elastically deformable circuit wiring with packaged microelectronics offer new opportunities to create high performance untethered systems. However, existing adhesive interconnects that form electrical and mechanical connections between the circuit wiring and electrical components often require selective patterning or high pressure and temperature, which is not compatible with liquid phase conductors, such as liquid metal (LM). Here, I introduce a stretchable anisotropic conductive film (S-ACF) composed of a LM mixture dispersed in an elastomer matrix that can be magnetically aligned and cured in place to form independent, vertical electrical interconnects. The resulting S-ACF is soft (E \u3c 1 MPa), has a low contact resistance (0.05 Ω mm−2), remains functional at high strains (\u3e100%), and is stable upon cyclic loading. I utilize the S-ACF to interface LM circuit wiring with surface mounted microelectronic components to create a stretchable, artificial electronic skin for tactile perception. The electronic skin is demonstrated as an active membrane and integrated with a robotic end effector to achieve tactile perception and robust manipulation. The S-ACF enables the creation of highly-functional, stretchable electronics for a variety of applications that require mechanical compliance. Advisor: Eric Markvick