Multifunctional conductive hydrogels based on the alkali lignin-Fe3+-mediated Fenton reaction for bioelectronics

Requirements for sustainable development have led to the urgent need for low cost, green, and reproducible resources. Lignin is one of the resources meeting this requirement. Herein, an alkali lignin (AL)-Fe3+-H2O2 autocatalytic system was introduced to assemble multifunctional AL-Fe3+/polyacrylic acid (PAA) hydrogels. The AL-Fe3+ pair-mediated Fenton reaction can generate a large number of free radicals to accelerate gelation. Owing to the abundant hydrogen bonds and metal coordination bonds, the AL-Fe3+/PAA hydrogels possessed excellent mechanical properties (tensile strength of 38 kPa), adhesion properties (18 kPa for pigskin), and self-healing ability (78 % for tensile strength and 88 % for tensile modulus). In addition, hydrogel-based sensors with high durability, strain sensitivity, and fast response times were employed to accurately monitor motion or electrophysiological signals. Subsequently, a portable sensing device for the wireless and remote monitoring of a user's motion status was integrated. As a result, an AL-Fe3+-H2O2 autocatalytic system has great potential for use in hydrogel preparation in flexible bioelectronics and wearable sensors. It can promote the sustainable devel-opment of flexible bioelectronics.

Automated summary

The introduction of an AL-Fe3+-H2O2 autocatalytic system allows for the assembly of multifunctional AL-Fe3+/polyacrylic acid hydrogels, which possess excellent mechanical properties, adhesion properties, and self-healing ability. Furthermore, hydrogel-based sensors with high durability and fast response times can accurately monitor motion or electrophysiological signals, and can be integrated into a portable sensing device for remote monitoring of a user's motion status. Therefore, the AL-Fe3+-H2O2 autocatalytic system shows great potential for sustainable development in flexible bioelectronics and wearable sensors.