Researchers at Korea Advanced Institute of Science and Technology (KAIST) have developed a stretchable pressure sensitive strain sensor by using an all solution-based process. This process can be applied in large areas and using a spray gun, it can be coated as a thin film on 3-D irregularly shaped objects. These properties make them highly suitable for electronic skin for robots or wearable electronic applications.
In the near future, prosthetic arms and legs will possess tactile sensitivity, but a lot of work still needs to be done. Among the challenges are uniformly covering complex 3D surfaces, such as the hand, with sensors and making the sensors tell the difference between different types of mechanical stimuli, especially between strain and pressure.
To overcome the obstacles, the research team led by Professor Steve Park from the Department of Materials Science and Engineering and Professor Jung Kim from the Department of Mechanical Engineering developed this electronic skin which can be uniformly coated on 3-dimensional surfaces and distinguish mechanical stimuli.
The researchers designed the structure of the electronic skin to respond differently under strain and pressure. When strain is applied, the conducting pathways experience significant conformational changes, which considerably changes the resistance. On the other hand, when pressure is applied, pathways undergo very little change. e-skin therefore is non-responsive to pressure. The researchers are currently working on strain insensitive pressure sensors to use with the newly developed strain sensors.
Using electrical impedance tomography (EIT), the team also spatially mapped the local strain without the use of patterned electrode arrays. By using EIT, it is possible to minimize the number of electrodes, increase durability, and enable facile fabrication onto 3-dimensional surfaces.
“Our electronic skin can be mass produced at a low cost and can easily be coated onto complex 3-dimensional surfaces. It is a key technology that can bring us closer to the commercialization of electronic skin for various applications in the near future,” said professor Park.
The study was published in the journal ACS Nano.