Porous Fibers Composed of Polymer Nanoball Decorated Graphene for Wearable and Highly Sensitive Strain Sensors

Abstract

Wearable textile strain sensors that can perceive and respond to human stimuli are an essential part of wearable electronics. Yet, the detection of subtle strains on the human body suffers from the low sensitivity of many existing sensors. Generally, the inadequate sensitivity originates from the strong structural integrity of the sensors because tiny external strains cannot trigger enough variation in the conducting network. Inspired by the rolling friction where the interaction is weakened by decreasing interface area, porous fibers made of graphene decorated with nanoballs are prepared via a prolonged phase‐separation process. This novel structure confers the graphene fibers with high gauge factors (51 in 0–5% and 87 in 5–8%), which is almost 10 times larger than the same structures without nanoballs. A low detection limit (0.01% strain) and good durability (over 6000 circles) are obtained. By the virtue of these qualities, these fiber‐based textile sensors can recognize a pulse wave and eyeball movement in real‐time while keeping comfortable wearing sense. Moreover, by weaving such fibers, the electronic fabrics with a specially designed structure can distinguish the multilocation in real time, which shows great potential as wearable electronics.

Ultralightweight and 3D Squeezable Graphene-Polydimethylsiloxane Composite Foams as Piezoresistive Sensors

“…16 Recently, researchers have also reported graphene-based fiber sensors for various strain monitoring applications. 31,34 A recently published review article presents a detailed overview of the developments in the field of flexible polymer-based strain sensors and discusses the recent developments in the field of electrically conductive polymer composites. 35…”

Single and bundled carbon nanofibers as ultralightweight and flexible piezoresistive sensors

“…In contrast, the concept of flexible sensors utilizing the piezoresistive property of flexible polymer materials is relatively new, and researchers across the world are investigating novel nanomaterial−polymer composites for developing wearable and flexible sensors [18][19][20][21][22][23] . Various conductive carbon-based nanomaterials, like graphene, carbon nanotubes (CNTs), carbon nanofibers (CNFs), and carbon blacks (CBs) have been explored by researchers 19,21,[23][24][25][26][27][28][29][30][31] . Also, various elastomeric materials like ecoflex, polyimide (PI), rubber, polydimethylsiloxane (PDMS), and polyurethane (PU) have been commonly used as the flexible polymer substrates due to their superior mechanical properties including compressibility, stretchability and excellent responsiveness to tension and torsion 19,21,22,32,33 .…”

“Self‐Matched” Tribo/Piezoelectric Nanogenerators Using Vapor‐Induced Phase‐Separated Poly(vinylidene fluoride) and Recombinant Spider Silk

“…Structures I–III show a porous structure while the dense morphology in structure IV shows poreless balls. The formation of these morphologies can be correlated to the compositional trajectories of the ternary phase diagram (PVDF/DMF/water) as shown in Figure e . Since the uptake of water from vapor is the major process of the phase‐separation, the changing component during this process, which is dependent on temperature ( T ) and relative humidity (RH), can create four major curves as marked in phase diagram (Figure e).…”