Wearable electronics for smart detection of patient body and fitness activity are a significant futuristic technology. Conventional strain sensors are inflexible and unsuitable for use on irregular surfaces such as human skin.
Study: Reduced graphene oxide-based stretchable strain sensor for monitoring of physical activities and minute movement. Image Credit: metamorworks/Shutterstock.com
A new work published in the journal Materials Today: Proceedings describes the construction of extremely flexible, accurate, and robust strain sensors employing electrochemically produced reduced graphene oxide (rGO).
Wearable Electronics: The Future of Monitoring Devices
Consumers in the medical and healthcare sector are progressively migrating toward controlled, customized, and monitored healthcare. The rapid advancement of mobile devices has helped the popularity of portable devices. Wearable technologies are emerging as excellent monitoring devices for healthcare services as a result of these improvements, particularly with increased emphasis on well-being, wellness, and disease management.
Wearable electronics are sophisticated internet of things gadgets that collect biometric information such as sleep habits and pulse rate. Wearables are used by consumers to correctly transmit vital exercise, physiological, and medical data to a database, which can be used to monitor the health of the patient.
The world has recently experienced the need for wireless healthcare monitoring with the outbreak of the devastating SARS-CoV-2 coronavirus. As a result, scientists have been attempting to develop smart wearable gadgets for continuous, real-time detection of patient health and physical activity.
Limitations of Traditional Strain Sensors
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.
Requirements for Advanced Wearable Devices
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.
Strain sensors used in wearable electronics should be structurally flexible to adapt to curved and soft surfaces such as human skin, chemically inert to sweating, and resilient to climatic variables such as temperature and humidity fluctuations.
Experiments on flexible strain sensors are now underway, with an emphasis on using nanoscale-based carbon materials to avoid the difficulties associated with stiff non-metal and semiconductors. Nanoscale carbon compounds may be utilized to make extremely flexible strain sensors.
Reduced Graphene Oxide (rGO) based Flexible Strain Sensors
Because of its exceptional electrical and magnetic capabilities, graphene has been touted 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.
Important Findings of the Study
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. Firstly, 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.
Verma, R. P. et al. (2022). Reduced graphene oxide-based stretchable strain sensor for monitoring of physical activities and minute movement. Materials Today: Proceedings. Available at: https://www.sciencedirect.com/science/article/pii/S2214785322031856?via%3Dihub