Flexible Piezoresistive Tactile Sensor Based on Polymeric Nanocomposites with Grid-Type Microstructure

作者：Da-Huei Lee, Cheng‐Hsin Chuang, Muhammad Omar Shaikh, Yong-Syuan Dai, Shaoyu Wang, Zhi‐Hong Wen, Chung-Kun Yen, Chien-Feng Liao, Cheng-Tang Pan · 发表于：Micromachines · 年份：2021 · DOI：10.3390/mi12040452 · 被引用次数：41 · 研究领域：Advanced Sensor and Energy Harvesting Materials、Tactile and Sensory Interactions、Analytical Chemistry and Sensors

Piezoresistive tactile sensors made using nanocomposite polymeric materials have been shown to possess good flexibility, electrical performance, and sensitivity. However, the sensing performance, especially in the low-pressure range, can be significantly improved by enabling uniform dispersion of the filler material and utilization of effective structural designs that improve the tactile sensing performance. In this study, a novel flexible piezoresistive tactile sensor with a grid-type microstructure was fabricated using polymer composites comprising multi-walled carbon nanotubes (MWCNTs) as the conductive filler and polydimethylsiloxane (PDMS) as the polymeric matrix. The research focused on improving the tactile sensor performance by enabling uniform dispersion of filler material and optimizing sensor design and structure. The doping weight ratio of MWCNTs in PDMS varied from 1 wt.% to 10 wt.% using the same grid structure-sensing layer (line width, line spacing, and thickness of 1 mm). The sensor with a 7 wt.% doping ratio had the most stable performance, with an observed sensitivity of 6.821 kPa−1 in the lower pressure range of 10–20 kPa and 0.029 kPa−1 in the saturation range of 30–200 kPa. Furthermore, the dimensions of the grid structure were optimized and the relationship between grid structure, sensitivity, and sensing range was correlated. The equation between pressure and resistance output was derived to validate the principle of piezoresistance. For the grid struc...