Strain-sensing polymer skin gives robots clever touch

The material, which also has potential applications in wearable electronics, could provide robots with sensory feedback to assist them with navigation and handling tasks. Its key innovation is embedding both electrical conductivity and strain-sensing into a single stretchy polymer, using meshed silver nanowires for both purposes. Up until now, researchers have used different materials for the sensing and conductive wiring components.

Each individual nanowire is conductive, but high resistance at the junctions between them limits overall conductivity through the material. Resistance increases significantly when the material is flexed and the nanowires are pulled apart such that the nanowire network acts as a strain sensor. Applying a DC voltage made the nanowire network very hot at the points of high resistance, where the nanowires meet. This localised heating acts to weld neighbouring nanowires together, forming a highly conductive firmly bonded network that the researchers claim is impervious to stretching and flexing. The work is described in the journal Advanced Electronic Materials.