Ultra-Tough Multifunctional Leather-Based e-Skin as Sensitive Multimodal Sensors for Strain, Temperature, Humidity, and Bioelectrical Signals

Abstract

Electronic skin (e-skin), an emerging class of flexible integrated electronic devices, is designed to replicate the multifaceted functionalities of human skin, playing a critical role in the realms of wearable technology and healthcare monitoring. Despite their potential, the existing e-skins often fall short in achieving the robust mechanical strength, multifunctionality, and biocompatibility necessary for real applications. Durability and aesthetic appeal are also highly valued. This study introduced an innovative, ultratough, multifunctional transparent leather-based e-skin that can address these challenges. By employing the natural microstructure of tanned goatskin as a substrate, this work created this e-skin with an interpenetrating network structure containing a cross-linked copolymer of acrylic acid (AA) and hydroxypropyl acrylate (HPA) and integrated a variety of functional fillers, including Zr-CQDs (zirconium-doped carbon quantum dots) for conductivity, curcumin for antibacterial properties, and the eutectic solvent comprised of ethylene glycol and choline dihydrogen citrate for antifreezing and moisturizing capabilities. This e-skin exhibited remarkable mechanical properties with a tensile strength of 11.92 MPa and exceptional toughness of 5.26 MJ/m³, alongside 70% light transmission, showcasing its transparency. Its multimodal sensing capabilities enabled precise monitoring of diverse environmental stimuli, including strain, temperature, humidity, and bioelectrical signals, representing a significant advancement in wearable sensor technology. This work not only breathes new life into traditional leather materials for contemporary applications but also paves the way for sustainable and functional e-skin innovations, pushing the boundaries of wearable technology.