High-sensitivity and damage redundant detection capable gel-state [BMIM][BF4] electronic skin for aerospace applications

Abstract

Electronic skin (e-skin) holds significant potential for applications in robotics, Internet-of-things, and health monitoring. However, conventional e-skins often exhibit decreased sensitivity and delayed response in ultra-low temperature environments due to the freezing of conductive materials. Moreover, an increased brittleness can cause substrate damage, limiting their application in cryogenic conditions. To address existing challenges, an ionic liquid [BMIM][BF₄] is cross-linked with N,N'-Bis(2-hydroxyethyl)oxamide to form an ionic gel for this study. The gel exhibits excellent electrical performance at −71 °C, significantly expanding the operating temperature range of e-skins. Additionally, gelation decreases resistive drift and leakage inherent to ionic liquids. The prepared sensing units demonstrate high sensitivity to pressure loading across an ultra-wide temperature range of −50–50 °C, with linear sensing within the range of 48–32,000 Pa and a rapid response time of 0.05 s. Integration of the units into large-scaled e-skin enables precise recognition of static and dynamic pressure loads in ultra-low temperature environments (−50 °C). Furthermore, a space glove model assembled using the sensing units achieves accurate recognition of hand gestures in extreme conditions. The sensing units retain over 60 % of their pressure response even when damaged, and demonstrate resilience to environmental factors including low temperatures and vacuum conditions. Along with exceptional performance and environmental resilience under harsh conditions, the gel-state [BMIM][BF₄] e-skin shows great potential in deep space exploration, polar expeditions, and other challenging environments.