Binary Synergistic Sensitivity Strengthening of Bioinspired Hierarchical Architectures based on Fragmentized Reduced Graphene Oxide Sponge and Silver Nanoparticles for Strain Sensors and Beyond

Abstract

Recently, stretchable electronics have been highly desirable in the Internet of Things and electronic skins. Herein, an innovative and cost-efficient strategy is demonstrated to fabricate highly sensitive, stretchable, and conductive strain-sensing platforms inspired by the geometries of a spiders slit organ and a lobsters shell. The electrically conductive composites are fabricated via embedding the 3D percolation networks of fragmentized graphene sponges (FGS) in poly(styrene-block-butadiene-block-styrene) (SBS) matrix, followed by an iterative process of silver precursor absorption and reduction. The slit- and scale-like structures and hybrid conductive blocks of FGS and Ag nanoparticles (NPs) provide the obtained FGS-Ag-NP-embedded composites with superior electrical conductivity of 1521 S cm , high break elongation of 680%, a wide sensing range of up to 120% strain, high sensitivity of ≈10 at a strain of 120%, fast response time of ≈20 ms, as well as excellent reliability and stability of 2000 cycles. This huge stretchability and sensitivity is attributed to the combination of high stretchability of SBS and the binary synergistic effects of designed FGS architectures and Ag NPs. Moreover, the FGS/SBS/Ag composites can be employed as wearable sensors to detect the modes of finger motions successfully, and patterned conductive interconnects for flexible arrays of light-emitting diodes.

Network cracks-based wearable strain sensors for subtle and large strain detection of human motions

“…15 Gauge factor (GF) is usually quantified to evaluate the sensitivity performance of stretchable sensors (GF = (DR/R)/e, where DR/R is the relative change in resistance and e is the applied strain). Ultrahigh GF easily leads to drastic structural changes at small deformations, [34][35][36][37][38][39][40][41] and further improve the sensitivity of such strain sensors.…”

A Flexible Wearable Pressure Sensor with Bioinspired Microcrack and Interlocking for Full‐Range Human–Machine Interfacing

“…Spiders have been regarded as the most sensitive animals to environmental vibrations due to their crack‐shaped vibration‐sensitive slit organ embedded in the exoskeleton . Inspired by the mechanosensory systems in spiders, researchers have established various crack‐shaped wearable pressure sensors, which benefit from the reversible crack connection . However, most crack‐shaped pressure sensors exhibit a limited monitoring range due to easily damaged conducting pathways, and their applications in real‐time detections of large‐strain deformations are inhibited.…”

Highly Stretchable, Adaptable, and Durable Strain Sensing Based on a Bioinspired Dynamically Cross‐Linked Graphene/Polymer Composite

“…There were two probable reasons for such nonlinearity, i.e., the intrinsic plasticity of the Gr–PAA–ACC sensor that was expressed under large deformation, and the change in the contact conditions for electron conduction in Gr–PAA–ACC upon stretching, such as break of contacts, contact area, spacing variations, etc . This was because upon stretching, the stacked crumpled Gr sheets in Gr–PAA–ACC composite would separate from each other, leading to smaller contact area, larger interspacing, or even break of contact at high strain, all of which would increase resistance . Note that the proposed the sandwich structure of Gr–PAA–ACC within two layers of VHB tape actually reduced wrinkling, sliding, and out‐of‐plane deformation, which could not realistically reflect the genuine use case scenario of stretchable strain sensors …”