Stretchable electronics and sensors, such as electronic skin, have wide ranging transformative applications in autonomous artificial intelligence (e.g. robots), medical diagnostics, and prosthetic devices capable of providing at least the same level of sensory perception as the biological equivalent. For example, for electronic skin to meet these expectations, a large number of distributed tactile sensors that are able to stretch and conform to curvilinear objects are required. Moreover, electronics that is conformal to human skin and deform in response to human motion requires stretchability. The functional requirements of stretchable electronics and sensors can be met through nano-enabled technologies, but their successful production requires innovation in scalable manufacturing and integration of processing methods. This Scalable NanoManufacturing (SNM) research project aims to investigate a scalable nanomanufacturing approach to fabricate large-area, high-resolution, stretchable electronics and sensor arrays by heterogeneous integration of metal nanowires and organic semiconductors. The research conducted as part of this award is integrated into interdisciplinary education for the involved students, course curriculum, and K-12 outreach. The project strongly encourages underrepresented students to participate in all aspects of the research.
Advancing the scalable nanomanufacturing of stretchable electronic skin requires: (1) stretchable functional materials (conductors, semiconductors), (2) a manufacturing strategy to integrate heterogeneous nanomaterials into a stretchable platform, and (3) optimal device design and integrated operation capabilities in both electronic and mechanical functionality. To meet these needs, the research investigates metal nanowires and polymer semiconductor material platforms. Stretchable conductors are achieved through forming nanowire-elastomer composites. Printing metal nanowires in large scale with high resolution is challenging. Here nanowire processing focuses on the fundamental understanding of the nanowire ink properties, ink-substrate interactions, and exploration of methods such as gravure and electrohydrodynamic printing. Approaches to achieve high-performance intrinsically stretchable polymer semiconductors are investigated with a focus on blending conjugated polymers with a secondary polymer matrix. Polymer semiconductor processing focuses on a combination of solution casting and advanced transfer printing methods. Device architecture and integrated manufacturing strategies are optimized to achieve high performance electronic-skin.
