Highly conductive fiber with design of dual conductive Ag/CB layers for ultrasensitive and wide‐range strain sensing

Abstract

Recently the ever‐increasing demand for wearable electronics has greatly triggered the development of flexible strain sensors. However, it is still challenging to simultaneously achieve high sensitivity, wide working range, and good wearability. Herein, we developed a highly stretchable fiber strain sensor based on wet‐spun porous polyurethane (PU) fiber, and especially a unique conductive network of dual silver (Ag)/carbon black (CB) layers is constructed. Under strain, the rapid crack propagation on the brittle Ag layer brings a large resistance change and thus high sensitivity, while the tunneling‐effect dominated CB layer bridges the separated Ag islands to maintain the integrity of conductive pathways under large strain. By means of the synergistic effect of Ag/CB layers, this composite fiber of Ag/CB@PU presents not only high conductivity of 5139.9 S/m, but also ultrahigh sensitivity with a gauge factor of 2.52 × 106 and a wide working range of up to 200%. Besides that, it is also capable of detecting very tiny strain of 0.1% and working stably for over 8000 cycles. Using mature weaving technology, this fiber strain sensor can be seamlessly integrated into the textile to conformally track different movements of the human body. Together with the facile all‐solution‐based fabrication protocol, this work proposed a new strategy to prepare high‐performance fiber strain sensor, promising the textile‐based wearable applications.

Pursuing Superhydrophobic Flexible Strain Sensors: From Design to Applications

“…In general, the linearity and durability of a superhydrophobic flexible strain sensor depends on the design of the sensing mechanism of the dual conductive layer, which can be improved by integrating hybrid sensing nanomaterials. [69] Han et al [70] applied a facile and controllable layer-by-layer spraycoating strategy to generate PDMS/CNT/CB dual conductive layers. This sensor exhibited high linearity (0.996 from 0% to 40%, 0.998 from 0% to 70%, and 0.992 from 0% to 90%, respectively), and the sensor's cyclic durability exceeded 30 000 cycles (Figure 4a).…”

“…In general, the linearity and durability of a superhydrophobic flexible strain sensor depends on the design of the sensing mechanism of the dual conductive layer, which can be improved by integrating hybrid sensing nanomaterials. [ 69 ] Han et al. [ 70 ] applied a facile and controllable layer‐by‐layer spray‐coating strategy to generate PDMS/CNT/CB dual conductive layers.…”

Innovations in spider silk‐inspired artificial gel fibers: Methods, properties, strengthening, functionality, and challenges

“…In addition, conductive gel fibers (PEDOT: PSS, 149 38 000 S m −1 ) (PEDOT/PANI, 150 200 S cm −1 ) (RGO-PEDOT:PSS-PVA, 101 114 S m −1 ) (PEDOT:PSS@PVA, 151 0.00163 S cm −1 ) (polyimide, 152 21 m S cm −1 ) (PAAS-PMA, 40 2 S m −1 ) (P(NAGA-co-AAm), 54 0.69 S m −1 ) (P(AAm-co-PAA)/Fe(III) 41 4.2 m S m −1 ) (lignin/core-cellulose nanofibrils [CNFs] 153 185.3 S cm −1 ) (IL@TPE, 154 ∼0.45 S m −1 ) (RCNFs, 155 0.07 S cm −1 ) (PEDOT:PSS/PEG, 156 50 S cm −1 ) (Ag/CB@PU, 157 5139.9 S m −1 ) having qualities of stretchability, improved conductivity, and consistency in electromechanical behavior are pivotal elements in the evergrowing realm of wearable technology. Here, Wu et al 158 reported a technique involving the shaping of a hydrogel reservoir into ultrathin and stretchable conductive fibers with remarkable self-healing and multi-responsive properties.…”

Recent development of conductive polymer composite‐based strain sensors

“…In addition, surface decoration usually corresponds to a core-shell structure, and the stretchability can be maintained to a great degree. Ultrasonication induced interface sintering, 72 dip-coating, 73 ion adsorption and insitu reduction 74 are the most common preparation methods to construct conductive networks on the fiber surface. Niu et al 75 developed a 1D PU fiber composite with a dual conductive grid structure consisting of CNTs The sectional view of a core-shell silicone fiber with 2 wt% MWCNT.…”