Stretchy electrodes that can keep up with an octopus

Abstract

Materials for bioelectronics must often strike a compromise between mechanical and electrical properties. In a talk at the ACS Fall 2022 meeting last week, Stanford University chemical engineer Zhenan Bao described her approach to designing polymers that bridge that gap, combining high electrical conductivity with soft, stretchy, tissue-like mechanical properties. Conductive polymers are in some ways ideal for making bioelectronics. Unlike conventional electronic materials, such as silicon and metal, they can be inherently soft and stretchable. But improving their electronic properties typically comes at a cost: the more crystalline a polymer is, the higher its electrical conductivity—and the less it will stretch. Bao and her team decided to separate out these competing priorities by developing a polymer that interlocks parts that are each optimized for conductivity, mechanical properties, or photopatternability. The best polymer design started with a polyethylene glycol (PEG) backbone strung with sliding cyclodextrin rings, which were decorated with