Engineering scientists at North Carolina State University have come up with strain amphibious sensors for deformation: stretching, bending, and movement. These sensors have applications in different areas perhaps many areas but most prominently in the biomedical engineering where they might be used to monitor blood vessels and other biological systems.
“Strain sensors are getting consideration for biomedical application, including the monitoring of blood vessels,” quote Shuang Wu, the study’s first author, and post-doctoral scholar of NC State. “In the same way, these sensors can be used to locate fish as it moves in the water body, observing the health of wild animals and other activities.”
Overview of the underwater strain sensor.
(a) Fabrication process of the amphibious strain sensor.
(b) The original sensor and the sensor after 20% stretching and twisting.
(c) The crack tip under the microscope at zero strain and 20% strain.
(d) Schematic side view of the three-layer structure of the strain sensor.
(e) Side view of the strain sensor under the microscope at zero strain and at 20% strain.
One of the major issues in creating wearable or implantable strain sensors is their performance in wet conditions, as Zhang notes and Yong Zhu, the paper’s corresponding author, and Andrew A Adams Distinguished Professor of Mechanical and Aerospace Engineering at North Carolina State University. ‘This was the goal we set ourselves; the creation of sensors that do not degrade in performance after a long time in a wet environment,’ said Zhu.
To achieve this, the research team extended a works-in-progress strain sensor formulated by the team in late November 2022. They encapsulated this sensor between two thin films of a highly elastic and water proof polymer. This way, the interface of the polymer prevents water from entering, while at the same time allowing the sensor to maintain its full range of motion since it is sensitive as well as stretchable. The sensor should be capable of linking to a chip of tiny size for the transfer of information through wireless mode.
According to Wu, the amphibious sensors proved to be highly sensitive and had almost an instant response in the trials. Thus, while performing their function they were not influenced by being in air, and remained fully effective even after 20 days in saltwater.
Zhu further said that the sensors were also very stable and could continue performing the sensing of the stretching regardless of the number of times the stretch reached up to 16,000.
To demonstrate the functions of the sensors, the researchers employed them to record the behavior of robotic fish, and detect pig’s heart blood pressure. It also incorporated the sensors into a glove that can translate scuba diver’s sign language into messages that can be understood by persons both on water and on land.
“Well the concept of the creation was to provide an effective form of communication network for scuba divers with fellow divers or members of a boat crew,” Wu explained.
The invention of this technology has raised the interest of the research team and is applying for the patent , Zhu said; Currently the research team is seeking for partners from different fields to explore the possibilities of the application of this technology.
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