Multifunctional Filler-Free Pedot:Pss Hydrogels with Ultra-High Electrical Conductivity Induced by Levwis Acid Promoted Ion Exchange.

Highly conductive hydrogels with bio-tissue-like mechanical properties are of great interest in the emerging field of hydrogel bioelectronics due to their good biocompatibility, deformability, and stability. Fully polymeric hydrogels may exhibit comparable Young's modulus to bio-tissues. However, most of these filler-free hydrogels have a low electrical conductivity of <10 S/cm which limits their wide applications of them in digital circuits or bio-electronic devices. In this work, we reported a series of metal halides doped poly(3,4-ethylenedioxy thiophene): poly(styrene sulfonate) (PEDOT:PSS) hydrogels with an ultrahigh electrical conductivity up to 547 S/cm, which is 1.5-10 4 times higher than previously reported filler-free polymeric hydrogels. Theoretical calculation demonstrated that the ion exchange between PEDOT:PSS and the metal halides played an important role to promote phase separation in the hydrogels, which thus leads to ultrahigh electrical conductivity. The high electrical conductivity resulted in multifunctional hydrogels with high performance in thermoelectrics, electromagnetic shielding, Joule heating, and sensing. Such flexible and stretchable hydrogels with ultrahigh electrical conductivity and stability upon various deformations are promising for soft bioelectronics devices and wearable electronics. This article is protected by copyright. All rights reserved.