Self-adhesive and conductive hydrogels and their applications in bioelectronics

Abstract

At present, the market pressure strain sensors mainly include intrinsic conductivity, composite conductivity, and flexible metal conductivity. Most of the strain sensors can met various basic requirements such as strain sensitivity and mechanical properties. However, biocompatibility and the ease of use are still areas to be explored and improved. This paper proposes a novel strategy to fabricate a kind of self-adhesive and conductive hydrogel using natural biomacromolecule gelatin, tannic acid (TA) and conductive polymer PEDOT: PSS. The sensor is biocompatible, nontoxic, and can be directly attached to the skin without the use of adhesive tape, and sufficiently large electrical signal response can be collected under stress. The presence of tannic acid forms a cross-linking network with the gelatin in the organic hydrogel, which can effectively increase the toughness (which can reach 203.62 kPa/m3). PEDOT: PSS provides the conductivity for the hydrogel, and hydrogel with 0.3wt% PEDOT: PSS content have a conductivity of about 2.1ms/cm. Therefore, this study found the possibility of making a flexible electronic element by using a composite of PEDOT: PSS, gelatin, and TA.