Large‐Area Compliant, Low‐Cost, and Versatile Pressure‐Sensing Platform Based on Microcrack‐Designed Carbon Black@Polyurethane Sponge for Human–Machine Interfacing

Abstract

It is a challenge to manufacture pressure‐sensing materials that possess flexibility, high sensitivity, large‐area compliance, and capability to detect both tiny and large motions for the development of artificial intelligence products. Herein, a very simple and low‐cost approach is proposed to fabricate versatile pressure sensors based on microcrack‐designed carbon black (CB)@polyurethane (PU) sponges via natural polymer‐mediated water‐based layer‐by‐layer assembly. These sensors are capable of satisfying the requirements of ultrasmall as well as large motion monitoring. The versatility of these sensors benefits from two aspects: microcrack junction sensing mechanism for tiny motion detecting (91 Pa pressure, 0.2% strain) inspired by the spider sensory system and compressive contact of CB@PU conductive backbones for large motion monitoring (16.4 kPa pressure, 60% strain). Furthermore, these sensors exhibit excellent flexibility, fast response times (<20 ms), as well as good reproducibility over 50 000 cycles. This study also demonstrates the versatility of these sensors for various applications, ranging from speech recognition, health monitoring, bodily motion detection to artificial electronic skin. The desirable comprehensive performance of our sensors, which is comparable to the recently reported pressure‐sensing devices, together with their significant advantages of low‐cost, easy fabrication, especially versatility, makes them attractive in the future of artificial intelligence.

Lightweight conductive graphene/thermoplastic polyurethane foams with ultrahigh compressibility for piezoresistive sensing

“…Unlike the monotonous response pattern of other CPC foams, an obvious deflection point was observed in both the compression and releasing processes during the cyclic compression. 61,62 For the first cycle, the resistance variation in the compression process displays a similar tendency to the result displayed in Fig. 9(c) due to the destruction of the cell structure.…”

Large‐Area Fabrication of High‐Performance Flexible and Wearable Pressure Sensors

“…Unlike most of the reported pressure sensors with top-bottom electrodes, [1,4,8,9,12,16,[18][19][20][21][22][23][24][25] here, we propose a printable side-by-side electrode configuration (Figure 1b), which makes it easy to miniaturize the sensor format (4 mm × 2 mm, Figure 1c) and also easy to create sensor arrays with self-defined patterns. Unlike most of the reported pressure sensors with top-bottom electrodes, [1,4,8,9,12,16,[18][19][20][21][22][23][24][25] here, we propose a printable side-by-side electrode configuration (Figure 1b), which makes it easy to miniaturize the sensor format (4 mm × 2 mm, Figure 1c) and also easy to create sensor arrays with self-defined patterns.…”

“…Topbottom electrode configurations are the mostly reported sensor layouts with three common scenarios: 1) the pressure-sensing layer is sandwiched between two electrodes; [18][19][20][21][22][23] 2) a conductive pressure-sensing microstructure used as an electrode is paired with a flat counter electrode; [4,24,25] and 3) two conductive microstructures are interlocked with each other. Topbottom electrode configurations are the mostly reported sensor layouts with three common scenarios: 1) the pressure-sensing layer is sandwiched between two electrodes; [18][19][20][21][22][23] 2) a conductive pressure-sensing microstructure used as an electrode is paired with a flat counter electrode; [4,24,25] and 3) two conductive microstructures are interlocked with each other.…”

Advanced carbon materials for flexible and wearable sensors

“…Recently, Wu et al [45] proposed a simple and cost-effective method to fabricate flexible pressure sensors based on the PU sponges decorated by carbon black. The …”

“…In particular, the selection of suitable active materials plays an important role in dominating the performance of sensors. To date, various materials, including carbon nanotubes (CNTs) [11,[26][27][28][29][30], graphene [31][32][33][34][35][36][37][38][39][40], carbon black [41][42][43][44][45], conductive polymers [16,[46][47][48], metal nanoparticles (NPs) and nanowires [21,[49][50][51][52][53][54][55], semiconductors [56,57], have been used as the active components for the fabrication of flexible sensors. Among these materials, metal NPs can be used to fabricate flexible sensors with high sensitivity, but the sensing range and stretchability of these sensors are limited [58].…”