Bio-inspired interlocking random 3-D structures for tactile and thermal sensing

Hierarchical nanostructures are tailored and used routinely in nature to accomplish tasks with high performance. Their formation in nature is accomplished without the use of any patterning process. Inspired by the performance of such structures, we have combined 2-D nanosheets with 1-D nanorods for functioning as electronic skin. These structures made in high density without any patterning process can be easily assembled over large areas. They can sense pressures as low as 0.4 Pa, with a response time in milliseconds. Further, these structures can also detect temperature changes with a non-linear response in the 298–400 K range, which is similar to skins perception of thermal stimuli. We illustrate this effect by showing that the device can differentiate between two 10 µl water droplets which are at room temperature and 323 K respectively.