Strain Sensor with Enhanced Sensitivity for Wearable Electronics Using an Over‐Balanced Planar Elastomer

Abstract

Flexible sensor technologies have gained extensive interest in recent yearsowing to the increasing demands of wearable electronics. Here, the authors propose a flexible strain sensor with enhanced sensitivity by designing a new sensing approach for strain detection. The sensing approach uses an over-balanced planar elastomer (OBPE) inspired by Kirigami-like auxetic structure for stretchable sensing. The OBPE substrate is designed and fabricated with four polydimethylsiloxane (PDMS) supporting beam embedded into Ecoflex elastomer to realize auxetic characteristics. The auxetic characteristics induce the sensing region of the sensor to expand in directions both along and orthogonally to the stretch loading. Consequently, the local disconnections of the electrically linked paths composed of multi-wall carbon nanotubes (MWCNTs) in the sensing region are enhanced. Gauge factor of the OBPE strain sensor is improved up to 6 times higher than the typical strain sensor without OBPE architecture. Therefore, the enhanced sensor outputs the stronger electrical signals than the typical sensor in perceiving human motions. Moreover, the two-step casting fabrication is a low-cost process and suitable for large volume manufacturing. In addition, as this sensing method is independent of the constituent conductive materials, it has the potential to be further employed for developing other stretchable strain sensors.

Styrene–butadiene rubber‐based nanocomposites toughened by carbon nanotubes for wide and linear electromechanical sensing applications

“…It has been found that the GF or sensitivity can be greatly improved by designing the conductive path or creating a larger number of strain-induced cracks in the conducting path, resulting in a higher relative change. 38,39 It is believed that the conductive path deteriorates to a higher extent at higher strain levels compared to lower strains. With increasing strain, filler networks can break down, and the resistance becomes higher.…”

Stretchable and Sensitive Strain Sensors Based on CB/MWCNTs–TPU for Human Motion Capture and Health Monitoring

“…Strain sensors made of rigid materials are unsuitable for applications like E-skin, human–machine interaction, and human motion or health monitoring due to their inherent characteristics such as high brittleness, large weight, and small strain sensing range. Thus, flexible strain sensors have emerged in recent years because of their good stretchability and flexibility. − How to achieve high performance of the flexible sensors has been one of the popular research trends in the development, namely, finding effective approaches to improve the working range, , sensitivity, − durability, − or low detection. , Among these properties, sensing range and sensitivity are the most critical performance indices of flexible strain sensors. , Among these properties, sensing range and sensitivity are the most critical performance indicators for flexible strain sensors. However, existing sensors generally have the deficiencies of high sensitivity and small sensing range, or large sensing range and low sensitivity.…”