Hydrogels have emerged as promising materials for the construction of skin-like mechanical sensors. The common design of hydrogel-based artificial skin requires a dielectric sandwiched between two hydrogel layers for capacitive sensing. However, such a planar configuration limits the sensitivity, stretchability and self-healing properties. Here, we report the design of single-layer composite hydrogels with bulk capacitive junctions as mechanical sensors. We engineer dielectric peptide-coated graphene (PCG) to serve as homogenously dispersed electric double layers in hydrogels. Any mechanical motions that alter the microscopic distributions of PCG in the hydrogels can significantly change the overall capacitance. We use peptide self-assembly to render strong yet dynamic interfacial interactions between the hydrogel network and graphene. The resulting hydrogels can be stretched up to 77 times their original length and self-heal in a few minutes. The devices can effectively sense strain and pressure in both air and aqueous environments, providing tremendous opportunities for next-generation iontronics.

中文翻译：

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可拉伸和自愈的水凝胶人造皮肤

水凝胶已成为构建类皮肤机械传感器的有前途的材料。基于水凝胶的人造皮肤的常见设计需要夹在两个水凝胶层之间的电介质以进行电容感应。然而，这种平面结构限制了灵敏度、拉伸性和自愈性能。在这里，我们报告了具有大容量电容结的单层复合水凝胶作为机械传感器的设计。我们设计了介电肽涂层石墨烯 (PCG)，以作为水凝胶中均匀分散的双电层。任何改变水凝胶中 PCG 微观分布的机械运动都会显着改变整体电容。我们使用肽自组装来呈现水凝胶网络和石墨烯之间强大而动态的界面相互作用。由此产生的水凝胶可以在几分钟内被拉伸到其原始长度的 77 倍并自我修复。这些设备可以有效地感应空气和水环境中的应变和压力，为下一代离子电子学提供了巨大的机会。