School of Biomedical Engineering, Shenzhen University, Shenzhen 518060, China.
Nanoscale. 2019 Jan 23;11(4):1570-1578. doi: 10.1039/c8nr08589g.
Flexible strain sensors that can be comfortably attached onto the skin for real-time and accurate detection of physiological signals are particularly important for the realization of healthcare, soft robotics and human-machine interfacing. It is still challenging to develop strain sensors that satisfy both high stretchability and high sensitivity. Here, we demonstrate an ultra-stretchable, highly sensitive and biocompatible capacitive-type strain sensor based on a nanocomposite containing ionic hydrogels and silver nanofibers (AgNFs). The sensor exhibits an ultra-high stretchability of 1000% and high sensitivity with a maximum gauge factor (GF) of up to 165. We find that the incorporation of AgNFs greatly increases the electrical-double layer (EDL) area at the hydrogel/metal interface and hence enhances by 3 orders of magnitude the strain sensitivity. With a short response time and good operation stability, the sensor and its matrix were successfully applied to monitor various physiological signals such as arm and finger motions, pulse, electrocardiographs (ECG), breath, speaking and emotion changes.
可舒适贴合皮肤的柔性应变传感器对于实现医疗保健、软机器人和人机交互至关重要，因为它们能够实时、准确地检测生理信号。开发同时满足高拉伸性和高灵敏度的应变传感器仍然具有挑战性。在这里，我们展示了一种基于包含离子水凝胶和银纳米纤维（AgNFs）的纳米复合材料的超拉伸、高灵敏度和生物相容性的电容式应变传感器。该传感器具有 1000%的超高拉伸性和高达 165 的高灵敏度，其最大应变系数（GF）可达 165。我们发现，AgNFs 的加入大大增加了水凝胶/金属界面处的双电层（EDL）面积，从而使应变灵敏度提高了 3 个数量级。该传感器具有短的响应时间和良好的操作稳定性，其传感器及其基体成功地应用于监测各种生理信号，如手臂和手指运动、脉搏、心电图（ECG）、呼吸、说话和情绪变化。
