Construction of Conductive Polymer Coatings onto Flexible PDMS Foam Composites with Exceptional Mechanical Robustness for Sensitive Strain Sensing Applications

Abstract

Flexible piezoresistive‐sensing materials with high sensitivity and stable sensing signals are highly required to meet the accurate detecting requirement for human motion. Herein, a conductive poly(3,4‐ethylenedioxythiophene): poly(styrenesulfonate) / polydimethylsiloxane foam (P:P@p‐PSF) composite with strong interfacial action is designed. The porous structures and good interface combination not only show outstanding mechanical flexibility and reliability but also possess high sensitivity at a relatively wide strain range. The P:P@p‐PSF sensor achieves extreme sensitivity (Gauge Factor) of 6.25 in the subtle strain range of 1%–8%. Furthermore, the sensor forms a highly interconnected conductive network induced by the serious deformation of elastic‐interconnect pores, thus providing extremely sensitive sensing behavior for a relatively wide strain range (97.4% resistance change rate at 60% compressive strain). Moreover, the sensor presents repeatable stability and good thermal adaptation, which would meet the critical requirements of subtle vital signs, human motion monitoring, and so on. This work supplies insight into the design of a new flexible sensor material to overcome the weak interface problem and the flexible mismatch between conductive filler and matrix, showing great application potential in the field of electronic skin.

Transient Piezoresistive Strain Sensors Based on Elastic Biopolymer Thin Films

“…Stable and consistent resistance changes without significant signal degradation were recorded, as shown in Figure e. This indicates that the as-developed sensors exhibit a stable sensing performance, similar to sensors based on conductive poly(dimethylsiloxane) foams developed by Chen et al and Nie et al , This demonstrates that the elastic biopolymer thin film can be a good alternative to poly(dimethylsiloxane) as the elastic building block for creating wearable sensors. Moreover, Li et al developed a nanocomposite hydrogel for strain sensing, maintaining consistent relative resistance during cyclic loading–unloading.…”

Polydopamine/Carbon Black/Carbon Nanofiber/Thermoplastic Polyurethane Composite Nanofiber Strain Sensor with Ultrahigh Loading Rate for Human Activity Monitoring

“…Therefore, it can be linked to a low-voltage driver or low-precision signal collector, and has lower signal processing accuracy requirements and larger error tolerance space, which proves the excellent applicability and reliability of PCCT. Comparing the PCCT with other schemes in the articles, the two parameters that GF in the common strain response interval of 0–100% and the approximate cost of the active filler were used as the judging indexes, respectively, and the obtained results are shown in Figure b, which shows that the PCCT achieves an excellent performance over most of the schemes based on a lower cost, proving the validity and significance of our work. ,,,,− Importantly, optimizing the encapsulation process or materials to reduce the interference of the encapsulation layer with the conductivity of the sensitive element can further improve the sensing performance of the device and extend the benefits of the polarity-induced mechanism.…”

“…(a) Relative change of resistance of PCCT with effect of tensile strain. (b) Comparison of data for PCCT with schemes from other articles. ,,,,− (c) Response time and recovery times of PCCT. (d) Effect of tensile velocity on the response stability of PCCT.…”

Preparation of Conductive Silicone-Rubber Composites by Dynamic Magnetic Field-Induced Orientation of Ferrosoferric Oxide-Loaded Reduced Graphene Oxide

“…With the continuous development and innovation of electronics, energy storage, and transportation, soft silicone-rubber (SR) conductive composites that can withstand high and low temperatures are widely used in electromagnetic-interference shielding materials, electrostatic-charge dissipation, spark-resistant rubber-contact switches, pressure-sensitive sensors, circuit components in microelectronics, and so on. − However, SR is an inert material; thus, achieving a significant increase in its conductive coefficient requires the addition of a large amount of conductive fillers (≥65 wt % of fillers). − This not only greatly increases the density and cost of the material, but also leads to poor electrical, and degradation of mechanical, optical properties and processing-performance. Meanwhile, the method of improving electrical conductivity through conductive filler-coated porous SR matrix composites suffers from the long processing time of the manufacturing method, the use of hazardous solvents, the mismatch of flexibility between the rigid conductive particle layer and the elastic matrix, and the weak interaction between the filler and the matrix leading to interfacial debonding . Therefore, developing new design and fabrication strategies is important for constructing conductive channels with minimal filler content to prepare efficient conductive SR composites.…”

“…However, controlled gradient conducting materials that do not require hierarchical preparation have been rarely reported. Chen et al and Nie et al utilized conductive fillers to coat porous materials, resulting in excellent electrical conductivity. However, the method of externally induced filler orientation offers the advantage of easier processing and the ability to control the filler orientation structure within the composite.…”