Reduced graphene oxide enables stretchable strain sensor for monitoring of physical activities

A new work by scientists at India's National Institute of Technology Rourkela describes the fabrication of extremely flexible, accurate, and robust strain sensors employing electrochemically produced reduced graphene oxide (rGO).

Conventional silicon-based strain sensors have relatively low flexibility of less than 5% and inadequate responsiveness, making them unsuitable for detecting both small and large strains. Aside from the flexibility constraint, typical silicon-based strain sensors need sophisticated manufacturing procedures such as microelectromechanical and deposition of thin films. Flexibility, responsiveness, and endurance are critical characteristics of wearable devices because they aid in the integration of the sensors over non-uniform interfaces such as the human body. Aside from elasticity, these products also need a sensor capable of detecting minute deformations caused by physiological factors and physical activity.

Thanks to its exceptional electrical and magnetic capabilities, graphene is seen as a potential sensing material. Using electrochemically separated rGO flake and flexible silicone-based sealer, a sustainable, cost-efficient, extremely elastic, ultrasensitive, and durable robust strain sensor was developed in this work.

An X-ray diffractometer (XRD) and a field emission scanning electron microscope (FESEM) were used to analyze the rGO. The rGO/silicone strain sensors were then used in wearable devices to track numerous physiological movements such as hand folding, wrist rotation, finger flexing, and knee rotation. The manufactured sensor was also used to identify disturbances in unsafe containers and detect the above-mentioned physical activities.

The researchers used the electrolytic approach to create a large-scale rGO flake, and its characteristics were assessed using FESEM, XRD, a tensile and flexural machine, and a multi-meter. The suggested manufacturing technique is simple, environmentally safe, and cost-effective. The combination of big flakes of rGO and an elastic silicone-based paste contributed to the development of a potential flexible strain sensor with flexibility of 116%, sensitivity of 4100, and endurance of 4550 cycles.

The flexibility of the sensors arises as a consequence of body movements, which results in the splitting and reconnecting of the conductive channels, altering the resistivity of the rGO/silicone detector. The rGO/silicone sensor was installed on the heels to observe the sensor's reaction while walking and running. The sensor displayed a consistent pattern matching the physical activity being performed.

It may be deduced that the sensor's real-time reaction can be applied to track physical activity such as leaping and unexpected falls. Furthermore, the flexible strain sensor's use is not restricted to wearable technology; it may also be used in a variety of sectors such as structural mapping and monitoring, automation, man-machine interaction, and touch recognition.

Posted: May 15,2022 by Roni Peleg