Beijing Key Laboratory of Advanced Functional Polymer Composites, Beijing University of Chemical Technology, Beijing 100029, China; State Key Laboratory of Organic-Inorganic Composites, College of Materials Science and Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
Beijing Key Laboratory of Advanced Functional Polymer Composites, Beijing University of Chemical Technology, Beijing 100029, China.
J Colloid Interface Sci. 2019 Apr 15;542:54-62. doi: 10.1016/j.jcis.2019.01.123. Epub 2019 Jan 29.
Flexible pressure sensors still face a great challenge to combine fast frequency response, wide pressure range, multiple detection modes, satisfactory mechanical and environmental stability, and simple fabrication process into a sensor. Herein, flexible piezoresistive pressure sensors are fabricated by treating the backbone of polyurethane (PU) sponge with chitosan (CS) to obtain positively charged CS@PU sponge, followed by dip-coating of negatively charged TiCT MXene sheets. The resulting MXene@CS@PU sponge-based sensor provides a versatile sensing platform with potentials for detecting both small and large pressure signals. Due to the highly compressive resilience of the PU sponge and its polar interaction with the MXene sheets, the MXene@CS@PU sensor has high compressibility and stable piezoresistive response for compressive strains of up to 85% with a stress of 245.7 kPa, and it also exhibits a satisfactory reproducibility for 5000 compression-release cycles. Even after washing in water for 1 h, the sensor still shows good performances. With a rapid response time of only 19 ms and a low detection limit of 30 μN corresponding to a pressure of 9 Pa, the MXene sponge sensor is promising for detecting human physiological signals and insect movements. In addition to the contact mode detection, the sponge sensor could detect voices and human breaths by a non-contact detection mode.
柔性压力传感器仍然面临着很大的挑战，需要将快速频率响应、宽压力范围、多种检测模式、令人满意的机械和环境稳定性以及简单的制造工艺结合到一个传感器中。本文通过用壳聚糖（CS）处理聚氨酯（PU）海绵的骨架，得到带正电荷的 CS@PU 海绵，然后再进行带负电荷的 TiCT MXene 片的浸渍涂覆，制备了柔性压阻压力传感器。基于 MXene@CS@PU 海绵的传感器提供了一个多功能的传感平台，具有检测小压力信号和大压力信号的潜力。由于 PU 海绵具有高压缩弹性和与 MXene 片的极性相互作用，MXene@CS@PU 传感器具有高的可压缩性和稳定的压阻响应，在高达 245.7 kPa 的压力下可压缩应变高达 85%，并且在 5000 次压缩-释放循环中也表现出令人满意的重现性。即使在水中清洗 1 小时后，传感器仍表现出良好的性能。该传感器具有仅 19 ms 的快速响应时间和 30 μN 的低检测限（对应于 9 Pa 的压力），有望用于检测人体生理信号和昆虫运动。除了接触模式检测外，海绵传感器还可以通过非接触检测模式检测声音和人类呼吸。
