Highly Stable and Sensitive Paper-Based Bending Sensor Using Silver Nanowires/Layered Double Hydroxides Hybrids

Abstract

Highly sensitive flexible piezoresistive materials using silver nanowires (AgNWs) composites have been widely researched due to their excellent electrical, optical, and mechanical properties. Intrinsically, AgNWs tend to aggregate in polymer matrix because of the intense depletion-induced interactions, which seriously influence the percolation threshold of the composites. In this study, we report a highly stable and sensitive paper-based bending sensor using the AgNWs and layered double hydroxides (LDHs) to construct a hybrid conductive network in waterborne polyurethane that is easy to destruct and reconstruct under bending deformation. The nonconductive 2D LDH nanosheets are embedded into AgNWs network and assist dispersion of AgNWs, which depends on the hydrogen bonding between the two nanostructures. The percolation threshold of the composites decreases from 10.8 vol % (55 wt %) to 3.1 vol % (23.8 wt %), and the composites reaches a very low resistivity (10(-4) Ω·cm) with a small amount of AgNWs (8.3 vol %) due to the dispersion improvement of AgNWs with the effect of LDH nanosheets. The as-prepared conductive composites with low percolation threshold can be manufactured on paper via various methods such as rollerball pen writing, inkjet printing, or screen printing. The bending sensor prepared by manufacturing the composites on paper shows low-cost, excellent conductivity, flexibility (>3000 bending cycles), sensitivity (0.16 rad(-1)), fast response (120 ms) and relaxation time (105 ms), and nontoxicity. Therefore, a simple but efficient wearable sensor is developed to monitor the human motions (such as fingers and elbow joints movements) and presents good repeatability, stability, and responsiveness, making the bending sensor possibly able to meet the needs in numerous applications for robotic systems.

Bio-based graphene/sodium alginate aerogels for strain sensors

“…When the hybrid aerogel suffers from different ranges of compressive strains from 30%-70% during the loading-unloading process, electrical resistance changes can accommodate to the change of applied strains (Fig. Considering the bending deformations can also tighten the 3D graphene conductive networks, the as-prepared hybrid aerogel are desirable for applications as bending sensors 44 . The stability of the hybrid aerogel is researched by applying a cyclic 50% strain on the hybrid aerogel (Fig.…”

Paper-based origami flexible and foldable thermoelectric nanogenerator

“…Moreover, there has been diverse efforts to combine distinctive materials with the paper itself for it to acquire conductive or semiconductive characteristics and become an active electronic material [15][16][17][18]. For example, researchers have made use of this approach to implement and demonstrate diverse applications such displays, sensors, radio frequency identification tags (RFID), energy harvesting and storage devices [19][20][21][22][23][24][25][26][27][28][29][30][31][32]. Particularly, paper-based energy harvesting devices have been developed to make use of mechanical or thermal energy, electrostatics, the triboelectric effect and others, mainly by functionalizing the paper with integrated nanomaterials or other metallic/polymeric composites [26,[33][34][35].…”

Multiscale Wrinkled Microstructures for Piezoresistive Fibers

“…Even though great efforts have been made to fabricate flexible piezoresistive fibers, such as graphene, carbon nanotubes, and silver nanowires (AgNWs)‐based piezoresistive sensors have been widely reported in recently years, it is very difficult to simultaneously satisfy high conductivity, stretchability, and sensitivity. It is generally accepted that a higher conductivity is conducive to design sensitive flexible piezoresistive materials driven by lower voltage . Generally, the conductivity is primary related to the conductive fillers.…”