High Sensitivity and a Wide Sensing Range Flexible Strain Sensor Based on the V-Groove/Wrinkles Hierarchical Array

Abstract

Flexible strain sensors occupying a large part of human body detection and wearable electronics, which have a wide sensing range and high sensitivity, are crucial in fully monitoring human motion signals. This study proposed a strategy to construct flexible strain sensors based on the V-groove/wrinkles hierarchical array. The V-groove array was prepared on a polydimethylsiloxane (PDMS) substrate through mold transfer printing. The gold film was sputtered on the prestretching PDMS substrate, and the V-groove/wrinkles hierarchical array was formed after strain release. Compared with the sensors based on single-scale wrinkle structures and a V-groove array, the fabricated strain sensor with the hierarchical array showed high sensitivity (maximum gauge factor up to 2,557.71) and a wide sensing range (up to 45%). In addition, the dynamic characteristics of the sensor were investigated in detail, indicating that the sensor had a fast response (less than 130 ms), a low detection limit (0.1% strain), and good stability (almost no performance loss after 10,000 cycles). In practical applications, the sensor was used to detect sizable physical motion and weak physiological signals, demonstrating great potential application value in human motion detection. This study could provide new ideas for preparing high-performance flexible strain sensors.

Surface Wrinkling for Flexible and Stretchable Sensors

“…[10] For instance, sensors with micropyramid dielectric layers or wrinkled micropillar structures exhibited higher sensitivity and sensing range compared to planar sensors. [73] Recently, Ji et al [244] described a strategy for the fabrication of a flexible sensor with a broad sensing range and high sensitivity based on the V-groove/wrinkle hierarchical array using a mold transfer and prestretching method. The V-groove array improved the sensitivity of the sensor (GF:2557.71), while the wrinkled structure endowed its broad sensing range (up to 45%).…”

“…[ 73 ] Recently, Ji et al. [ 244 ] described a strategy for the fabrication of a flexible strain sensor with a broad sensing range and high sensitivity based on the V‐groove/wrinkle hierarchical array using a mold transfer and prestretching method. The V‐groove array improved the sensitivity of the sensor (GF:2557.71), while the wrinkled structure endowed its broad sensing range (up to 45%).…”

Piezoresistive Fibers with Large Working Factors for Strain Sensing Applications

“…21,24,25 Despite their large deformability (>500% strain) and high sensitivities, 26 piezoresistive nanocomposite fibers show very small working factors (W ≤ 5%). 27,28 This is due to the small yield strains (ε c ) for polymer hosts, 15 which closely correlate with W for most piezoresistive nanocomposite materials. 14,29 Thus, the performances of these materials are reliably restricted to the elastic regime.…”

Versatile nano–micro collagen fiber-based wearable electronics for health monitoring and thermal management

“…[19][20][21][22] To solve the possible nonlinear response of these sensors within a wide detection range and the large hysteresis behavior caused by an irreversible change to the conductive pathway, the microstructure on the piezoresistive strain sensors' conductive pathway was subtly designed. Thus far, various micro-structured exible substrates and nano-ller based strain sensor systems have been designed to improve the sensitivity and response range of exible strain sensors, including bers, 23,24 wrinkles, 25,26 arrays, 27,28 foams, 29,30 textiles, 31,32 papers, 33,34 and electrospinning lms, 35,36 among others. While this strategy has proven to be promising in improving performance, the construction of a complex nano-micro structure could not only complicate the preparation of the device but also render the realization of mass production challenging.…”