A one-step method of hydrogel modification by single-walled carbon nanotubes for highly stretchable and transparent electronics.

Electrically conductive hydrogels (ECHs) are attracting much interest in the field of biomaterial science due to their unique properties. However, effective incorporation and dispersion of conductive materials in the matrices of polymeric hydrogels for improved conductivity remains a great challenge. Here, we demonstrate highly transparent, electrically conductive, stretchable tough hydrogels modified by single-walled carbon nanotubes (SWCNTs). Two different approaches for the fabrication of SWCNT/hydrogel structures are examined: a simple SWCNT film transfer onto the as-prepared hydrogel and the film deposition onto the pre-stretched hydrogel. Functionality of our method is confirmed by scanning electron microscopy along with optical and electrical measurements of our structures while subjecting to different strains. Since the hydrogel-based structures are intrinsically soft, stretchable, wet and sticky, they well conform to a human skin. We demonstrate applications of our material as skin-like passive electrodes and active finger-mounted joint motion sensors. Our technique shows a promise to accelerate the development of bio-integrated wearable electronics.