Conductive hydrogels have shown great potential for fabricating flexible and wearable sensors, especially strain/pressure sensors to monitor human motion/health. In practice, the use of conductive hydrogel-based sensors is often limited because of hydrogels’ poor mechanical properties and low sensitivity. In the present article, a composite hydrogel comprising acrylamide, N-(3-aminopropyl) methyl acrylamide hydrochloride, and polydopamine-coated reduced graphene oxide is prepared. The dynamic covalent and noncovalent interactions that exist in the hydrogel matrix including C–N bonds, intra-/intermolecular hydrogen bonds and NH₃⁺–π interaction, and π–π interactions rendered the hydrogels with superior fracture stress (496.4 ± 85.9 kPa) and ductility (1156.9 ± 110.1%). Also, prepared hydrogels have excellent cytocompatibility and show appropriate adhesion to the skin, showcasing their potential in fabricating wearable devices. On the basis of these facts, hydrogel-based strain/pressure sensors that cause a change in resistance when strain or pressure is applied are fabricated. The fabricated sensors show a high strain sensitivity in the strain range of 0–800% where, at a subtle strain (100%), the gauge factor reached 5.4. In addition, sensors are also responsive to pressure with a sensitivity of −0.74% kPa^–1 in the range from 0 to 10 kPa. The fabricated strain/pressure sensors have the cyclic ability and self-healing property at room temperature. As a proof-of-concept, the sensors are shown to monitor movements of the elbow, knee, fingers, and wrists as well as sense the vocal cord vibration.

中文翻译：

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用于驱动应变和压力的高强度、可拉伸和导电还原氧化石墨烯复合水凝胶传感器

导电水凝胶在制造柔性和可穿戴传感器方面显示出巨大潜力，尤其是应变/压力传感器以监测人体运动/健康。在实践中，由于水凝胶的机械性能差和灵敏度低，基于导电水凝胶的传感器的使用通常受到限制。本文制备了一种由丙烯酰胺、N- (3-氨基丙基)甲基丙烯酰胺盐酸盐和聚多巴胺包覆的还原氧化石墨烯组成的复合水凝胶。存在于水凝胶基质中的动态共价和非共价相互作用，包括 C–N 键、分子内/分子间氢键和 NH ₃ ⁺–π 相互作用和 π–π 相互作用使水凝胶具有优异的断裂应力 (496.4 ± 85.9 kPa) 和延展性 (1156.9 ± 110.1%)。此外，制备的水凝胶具有出色的细胞相容性，并显示出对皮肤的适当粘附，展示了它们在制造可穿戴设备方面的潜力。基于这些事实，制造了在施加应变或压力时会引起电阻变化的基于水凝胶的应变/压力传感器。制造的传感器在 0-800% 的应变范围内显示出高应变灵敏度，其中在细微应变 (100%) 下，应变系数达到 5.4。此外，传感器还对压力敏感，灵敏度为 -0.74% kPa ^–1在 0 到 10 kPa 的范围内。制造的应变/压力传感器在室温下具有循环能力和自愈特性。作为概念验证，传感器可以监测肘部、膝盖、手指和手腕的运动，并能感知声带振动。