Recently, researchers recently demonstrated a new sensor technology that can work effectively in both air and underwater environments, paving the way for the development of versatile "amphibious" sensors with potential applications in a wide range of fields, including wildlife monitoring and biomedical research.
The new discovery focuses on strain sensors, which have the ability to measure the deformation of objects, i.e. detect the stretching, bending, and movement of objects. Shuang Wu, a postdoctoral researcher at North Carolina State University and first author of the paper, said: "There is a strong interest in developing strain sensors for biomedical applications, such as those that can be used to monitor the behavior of blood vessels and other biological systems. In addition, these sensors can be used to observe the activity of fish underwater, or to monitor the health of wildlife.”
However, the development of such wearable or implantable strain sensors presents a major challenge, namely how to ensure the stability and reliability of the sensor in wet environments. Yong Zhu, corresponding author of the paper and Andrew A. Adams Distinguished Professor of Mechanical and Aerospace Engineering at North Carolina State University, explains, "The main goal of our research is to create sensors that can be used in wet environments for long periods of time without loss of performance.”
Pictured: Amphibious sensors (Source: North Carolina State University)
To achieve this, the research team took a highly sensitive strain sensor they developed at the end of 2022 and sandwiched it between two layers of membranes made of highly elastic waterproof polymer. This polymer not only encapsulates the sensor, but also ensures the sensitivity and stretchability of the sensor due to its unique interface design, which effectively prevents moisture intrusion without restricting the extension of the sensor material. In addition, the sensor can be connected to a small wireless chip to transmit data remotely.
Experimental results show that the amphibious sensor not only has high sensitivity and fast response, but also has stable performance after 20 days of immersion in air or salt water. Professor Yong Zhu added, "The stability of the sensor is excellent, and even after 16,000 stretches, there is no degradation in performance.”
To validate the practical capabilities of the amphibious sensor, the researchers conducted a number of tests, including using the sensor to track the movement of robotic fish, monitoring the blood pressure of a pig's heart, and developing a glove with an integrated amphibious sensor. The glove converts the diver's hand gestures into signals that can be understood by both underwater and people on the water, providing divers with an effective way to communicate underwater.
"We wanted to create an easy way for divers to communicate effectively with their underwater companions or crew members on the surface," Wu said. Relevant validation test videos can be found online.
"We have filed a patent for this technology and look forward to working with industry partners to bring these sensors to more applications," said Professor Yong Zhu.”
