Key factors and performance criteria of wearable strain sensors based on polymer nanocomposites

Abstract

Recently, there has been a growing demand for wearable electronic devices/strain sensors in soft robotics body-health monitoring, human-machine interfaces and human motion detection. Wearable strain sensors feature fast and multi-stimuli sensitivity, high flexibility, ultra-stretchability and biocompatibility. Although the progress in flexible strain sensors is exponential, the production of wearable sensors undergoes several challenges, such as reliability and reproducibility. An in-depth understanding of the sensing mechanism of the flexible strain sensors based-polymeric nanocomposites is needed to fabricate reliable and reproducible sensors and move from the prototype phase into the industry phase. In this review, types of strain sensors and key parameters such as linearity, gauge factor (sensitivity), hysteresis and durability are explained in the context of the recently published work. In addition, current challenges and perspectives in relation to the wearable strain sensors are delineated.

Roadmap on printable electronic materials for next-generation sensors

“…One of the main potential applications of strain sensors based upon printed 2D materials is in the area of stretchable, skin-mounted and wearable strain sensors for healthcare monitoring [282]. The challenge of this application is that it requires strain sensors with a high gauge factor, based upon flexible low-modulus materials that are capable of measuring high levels of strain and being cycled reversibly many times without significant levels of hysteresis [327].…”

Sandwich-Like Flexible Breathable Strain Sensor with Tunable Thermal Regulation Capability for Human Motion Monitoring

“…Electrospinning micro/nanofiber films are typical substrate materials for constructing flexible resistive sensors and exhibit many advantageous features such as skinlike softness, high specific surface area, large porosity, excellent stretchability, and ease of fabrication. , To further endow the flexible nanofiber films with desirable sensing performances, various conductive nanomaterials are introduced via physical deposition or chemical bonding. − Typically, the emerging two-dimensional MXene, known for its exceptional electrical conductivity, large specific surface area, and abundant surface functional groups, shows promising potential in the fabrication of a sensing layer. − Numerous studies have highlighted the importance of constructing uninterrupted electron-transport channels in the fabrication of polymer/MXene-based resistive strain sensors. However, the conductive paths are susceptible to damage under repetitive deformation, thus severely decreasing the sensing stability of sensors. − On the other hand, the large resistance change caused by conductive nanomaterials in highly sensitive strain sensors and other flexible electronics will generate a mass of heat. This heat generation can adversely affect their performance, operation reliability, and service life.…”

Thermally stable metallic glass strain sensors with extended sensing range and sensitivity

“…Since the emergence of flexible devices and real-time monitoring technologies based on the internet of things, demand for high-performance wearable sensors, such as strain sensors, has continuously increased. 1–4 A strain sensor is a device that detects motion and deformation and converts the deformation into an electric signal. As commercially available strain sensors comprise rigid substrates that may not detect minute human signals and movements, wearable thin-film strain sensors that may be adhered to human skin are of interest to researchers.…”