Shin Woohyeon, Kim Jun Seop, Choi Hui Ju, Kim Heesung, Park Sulbin, Lee Hee Jung, Choi Moon Kee, Chung Kyeongwoon
Composites Research Division, Korea Institute of Materials Science(KIMS), Changwon, 51508, South Korea.
School of Materials Science and Engineering, Ulsan National Institute of Science and Technology(UNIST), Ulsan, 44919, South Korea.
Macromol Rapid Commun. 2021 May;42(9):e2100011. doi: 10.1002/marc.202100011. Epub 2021 Mar 10.
Hydrogels are attractive, active materials for various e-skin devices based on their unique functionalities such as flexibility and biocompatibility. Still, e-skin devices are generally limited to simple structures, and the realization of optimal-shaped 3D e-skin devices for target applications is an intriguing issue of interest. Furthermore, hydrogels intrinsically suffer from drying and freezing issues in operational capability for practical applications. Herein, 3D artificial skin devices are demonstrated with highly improved device stability. The devices are fabricated in a target-oriented 3D structure by extrusion-based 3D printing, spontaneously heal mechanical damage, and enable stable device operation over time and under freezing conditions. Based on the material design to improve drying and freezing resistance, an organohydrogel, prepared by solvent displacement of hydrogel with ethylene glycol for 3 h, exhibits excellent drying resistance over 1000 h and improved freezing resistance by showing no phase transition down to -60 °C while maintaining its self-healing functionality. Based on the improved drying and freezing resistance, artificial skin devices in target-oriented optimal 3D structures are presented, which enable accurate positioning of touchpoints even on a complicated 3D structure stably over time and excellent operation at temperatures below 0 °C without losing their flexibility.
水凝胶因其独特的功能，如柔韧性和生物相容性，成为各种电子皮肤设备中具有吸引力的活性材料。然而，电子皮肤设备通常局限于简单结构，实现适用于目标应用的最佳形状的3D电子皮肤设备是一个有趣的研究课题。此外，水凝胶在实际应用的操作能力方面存在固有的干燥和冻结问题。在此，展示了具有高度改进的设备稳定性的3D人工皮肤设备。这些设备通过基于挤出的3D打印以目标导向的3D结构制造，能自发修复机械损伤，并能在一段时间内以及在冷冻条件下实现稳定的设备运行。基于改善抗干燥和抗冻结性能的材料设计，通过用水凝胶与乙二醇进行3小时的溶剂置换制备的有机水凝胶，在超过1000小时的时间内表现出优异的抗干燥性能，并且通过在低至-60°C时不发生相变同时保持其自愈功能，提高了抗冻结性能。基于改进的抗干燥和抗冻结性能，展示了目标导向的最佳3D结构的人工皮肤设备，即使在复杂的3D结构上，也能随着时间的推移稳定地实现触摸点的精确定位，并且在低于0°C的温度下能出色运行而不失去其柔韧性。
