Janus and Heteromodulus Elastomeric Fiber Mats Feature Regulable Stress Redistribution for Boosted Strain Sensing Performance

Abstract

Wearable strain sensors have huge potential for applications in healthcare, human–machine interfacing, and augmented reality systems. However, the nonlinear response of the resistance signal to strain has caused considerable difficulty and complexity in data processing and signal transformation, thus impeding their practical applications severely. Herein, we propose a simple way to achieve linear and reproducible resistive signals responding to strain in a relatively wide strain range for flexible strain sensors, which is achieved via the fabrication of Janus and heteromodulus elastomeric fiber mats with micropatterns using microimprinting second processing technology. In detail, both isotropic and anisotropic fiber mats can turn into Janus fiber mats with periodical and heteromodulus micropatterns via controlling the fiber fusion and the diffusion of local macromolecular chains of thermoplastic elastomers. The Janus heterogeneous microstructure allows for stress redistribution upon stretching, thus leading to lower strain hysteresis and improved linearity of resistive signal. Moreover, tunable sensing performance can be achieved by tailoring the size of the micropatterns on the fiber mat surface and the fiber anisotropy. The Janus mat strain sensors with high signal linearity and good reproducibility have a very low strain detection limit, enabling potential applications in human–machine interfacing and intelligent control fields if combined with a wireless communication module.

Electrospun Micro/Nanofiber-Based Biomechanical Sensors

“…The unique topology structure broadens piezoelectric effects compared with the planar membrane. Jia et al 173 performed a pressing on an electrospun styrene-butadienestyrene (SBS) block copolymer nanofibrous membrane by a metal mesh at an optimal temperature and pressure. This process yielded Janus elastomeric nanofibrous membranes with periodic and isotropic micropatterns.…”

Janus Dual Self‐Strengthening Structure of Bi2O3/Gd2O3 Nanofibrous Membranes for Superior X‐Ray Shielding

“…[45,46] To confirm this conjecture, we simulated the velocity distribution in FJNMs and Bi 2 O 3 /Gd 2 O 3 flat film (Figure 4c). [47][48][49] The airflow field, which used color as a scale, showed that the exhibited colors of Bi 2 O 3 /Gd 2 O 3 flat film, which ranged from cyan to red, were noticeably different from the colors of blue for FJNMs, emphasizing the role of fibrous porous in boosting air permeability. The FJNMs have a promising heat diffusion pathway thanks to the high WVTR and air permeability.…”

Electrically Conductive AgNPs/TPU-Electrospun Fibers with Hierarchical Microstructures by a One-Step Method for a High-Performance Flexible Pressure Sensor

“…42,43 In recent years, electrostatic spinning technology for the preparation of microstructure-rich flexible sensors has also attracted increasing attention. 44 Under the pressure of a high-voltage electric field, as the solvent evaporates, polymer materials are jetted into a fine stream onto a collection device to form nanofiber mats, inside of which can form hierarchical microstructures. The method is simple, of low cost, and easy to achieve large-scale production, and the prepared nanofiber mats have good flexibility, air permeability, high specific surface area, and high porosity, which are particularly suitable for assembling high-performance pressure sensors.…”

“…Combined with other related research reports, it can be seen that these microstructure preparation processes can lead to improvements in sensor sensitivity and detection range . In practical applications, the complexity, ease of use, and cost of the designing and preparing the sensor microstructures are key considerations. , In recent years, electrostatic spinning technology for the preparation of microstructure-rich flexible sensors has also attracted increasing attention . Under the pressure of a high-voltage electric field, as the solvent evaporates, polymer materials are jetted into a fine stream onto a collection device to form nanofiber mats, inside of which can form hierarchical microstructures.…”