Fig. 1 |. MorphE using viscoplastic electronic materials.
a, Schematics showing adolescent development of the rat and the MorphE that conformally adapts to sciatic nerve growth. The MorphE is composed of two materials: PEDOT:PSS plasticized by a viscous additive (glycerol) serving as a soft conductor and a polymer blend of PDMS–IU and PDMS–IU0.6–MPU0.4 as a viscoplastic insulator. MorphE allows plastic deformation with little stress when stretched by a growing nerve. b, Image of MorphE after being stretched at 50% and 100% strain. It maintains the shape after force is released. c, Normalized resistance for untreated PEDOT:PSS (thickness: 2 μm) and PEDOT:PSS/glycerol (thickness: 2 μm) on VP substrate (length, 8 mm; width, 3 mm; thickness, 120 μm) under 150% strain. d, Uniaxial stress–strain curves for PEDOT:PSS/glycerol on VP substrate (length, 9 mm; width, 5 mm; thickness, 200 μm) at various strain rates. Stress at 100% strain for various strain rates, showing strain-rate-dependent viscoplastic behavior (inset). e, Creep-recovery tests for PEDOT:PSS/glycerol on VP substrate and PEDOT:PSS/glycerol on PDMS substrate. No recovery after force is released for PEDOT:PSS/glycerol/VP (length, 8 mm; width, 5.5 mm; thickness, 200 μm for both samples).