| Autor: |
Nguyen NT; Department of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K., Jennings J; Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K., Milani AH; Department of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K., Martino CDS; School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, U.K., Nguyen LTB; Eastman Dental Institute, University College London, London WC1X 8LD, U.K., Wu S; Department of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K., Mokhtar MZ; Department of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K., Saunders JM; Department of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K., Gautrot JE; School of Engineering and Materials Science, Queen Mary University of London, London E1 4NS, U.K., Armes SP; Department of Chemistry, University of Sheffield, Sheffield S3 7HF, U.K., Saunders BR; Department of Materials, University of Manchester, MSS Tower, Manchester M13 9PL, U.K. |
| Abstrakt: |
Highly stretchable electrically conductive hydrogels have been extensively researched in recent years, especially for applications in strain and pressure sensing, electronic skin, and implantable bioelectronic devices. Herein, we present a new cross-linked complex coacervate approach to prepare conductive hydrogels that are both highly stretchable and compressive. The gels involve a complex coacervate between carboxylated nanogels and branched poly(ethylene imine), whereby the latter is covalently cross-linked by poly(ethylene glycol) diglycidyl ether (PEGDGE). Inclusion of graphene nanoplatelets (Gnp) provides electrical conductivity as well as tensile and compressive strain-sensing capability to the hydrogels. We demonstrate that judicious selection of the molecular weight of the PEGDGE cross-linker enables the mechanical properties of these hydrogels to be tuned. Indeed, the gels prepared with a PEGDGE molecular weight of 6000 g/mol defy the general rule that toughness decreases as strength increases. The conductive hydrogels achieve a compressive strength of 25 MPa and a stretchability of up to 1500%. These new gels are both adhesive and conformal. They provide a self-healable electronic circuit, respond rapidly to human motion, and can act as strain-dependent sensors while exhibiting low cytotoxicity. Our new approach to conductive gel preparation is efficient, involves only preformed components, and is scalable. |
