Developing electronic skin with various senses has many applications - from rehabilitation, healthcare, prosthetic devices, to robotics and human machine interfaces. Stretchable pressure sensors lend the ability to detect numerous types of touch and pressure, a key component of this type of technology.
Teams from POSTECH and the University of Ulsan in Korea joined to create electronic skin as flexible as that of a crocodile. Crocodiles have this remarkable ability to sense small waves and detect the direction of prey as formidable predators. This is made possible by a sensitive sensory organ located on their skin that is made of hemispheric sensory bumps arranged in a repeated pattern with wrinkled hinges between them.
The research team mimicked the crocodile sensory organ’s structure and function by creating a hemispheric elastomeric polymer with wrinkles containing either long or short nanowires. The wrinkled structure allows unfolding which leads to the reduction of stress applied on the hemispheric sensing area. This device, which maintains exceptional sensitivity when subjected to mechanical deformation - 100% in one direction and 50% in two different directions - outperformed other available sensors.
In evaluating the performance of the pressure sensor, they mounted it onto a plastic crocodile and submerged it in water. The sensor was able to detect water waves, replicating the sensing capabilities of the crocodile’s sensory organ even under tensile strain.
With this result, the team made sure to have pressure sensors suitable for a wide range of wearable devices and applications.