A multidisciplinary team of researchers from various Chinese universities and institutions has designed a flexible and stretchable electronic skin whose embedded strain-sensors can actively drive color changes in a matrix of electrochromic layers.
Publishing their results in the journal 2D Materials under the title “Integration of graphene sensor with electrochromic device on modulus-gradient polymer for instantaneous strain visualization”, the researchers describe their bio-inspired colour-changing skin as the stretchable assembly of a highly sensitive resistive strain sensor made from graphene woven fabric (GWF) with a stretchable organic electrochromic device (ECD) using GWF as its stretchable electrodes.
The ECD itself consists of GWF as the electrode materials dip-coated with Polyaniline (PANI) as the organic electrochromic material which presents four redox states of different colours, yellow, green, blue and purple. Polyvinyl alcohol serves as the solid electrolyte.
What they found is that thanks to the highly strain sensitive nature of the graphene woven fabric, subtle strains from 0 to 10% were enough to drive clear color changes within a few seconds, which provided direct optical feedback on the applied strain.
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