基于导电涂层微结构TPU柔性传感器的制备和性能

Preparation and performance of flexible sensors based on microstructured thermoplastic polyurethane with conductive coatings

将具有表面微结构和平整的热塑性聚氨酯(TPU)传感基片封装成压阻型柔性压力传感器,其中前者(尺寸为10 mm×10 mm)的表面喷涂不同质量(0.02、0.05、0.1 g)的多壁碳纳米管(MWCNTs),并对微结构柔性传感基片表面形貌及传感器性能进行了表征和分析。结果表明,微结构传感基片表面上微柱顶面形成一定厚度的MWCNTs层,层内MWCNTs形成网络;喷涂较高MWCNTs质量时,传感器具有较高的灵敏度和较低的检测限,这归因于压力所致MWCNTs的网络搭接程度和传感基片间接触面积的增加量较大;喷涂0.1 g MWCNTs时,传感器的灵敏度为0.143 kPa^(-1)(0~3 kPa),检测限低至100 Pa,在较宽压力范围内(3~200 kPa)仍有一定的压阻响应,能在4 000次的循环压缩/释放测试(峰值压力约200 kPa)中保持稳定的压阻响应,且可准确检测典型人体运动所产生的压阻响应,具有应用于智能穿戴领域的潜能。

Flexible piezoresistive pressure sensors were prepared through assembling the surface-microstructural and the flat thermoplastic polyurethane sensing substrates. The surface of the microstructural substrate with a size of 10 mm×10 mm was sprayed with diffe-rent masses of multi-walled carbon nanotubes(MWCNTs)(0. 02,0. 05 and 0. 1 g). The surface morphology of the microstructural flexible sensing substrate and the performance of the sensors were characterized and analyzed. The results demonstrated that there was a carbon nanotube layer with a certain thickness formed on the top surfaces of the microcolumns on the microstructural substrate. The sensor based on the microstructural sensing substrate sprayed with a greater mass of MWCNTs exhibited a higher sensitivity and a lower detection limit. This may be attributed to greater increments in the pressure-induced overlap degree of the MWCNTs network and the contact area between the sensing substrates. The sensor based on the microstructural sensing substrate sprayed with 0. 1 g MWCNTs presented a higher sensitivity of 0. 143 k Pa^(-1)(0~3 kPa),a lower detection limit of 100 Pa,together with a certain piezoresistive response in the wide pressure range of 3~200 kPa. Moreover,the sensor maintained a stable piezoresistive response during the4 000-cycle compression/release test with a peak pressure of 200 kPa,and had an accurate detection capability toward the piezoresistive responses generated by typical human motions. The sensor exhibits great application potential for intelligent wearables.