Preparation and Performance of Multifunctional Composite Hydrogel Based on Xanthate Lignin/Chitosan/Poly(acrylic acid) with Underwater Adhesion and Sensing Properties

Multifunctional hydrogel materials with self-healing ability, underwater adhesion, and electrical conductivity have potential application value in many fields. In this study, an LS/CS/PAA composite hydrogel was prepared by one-pot method using lignosulfonate (LS), acrylic acid (AA), and chitosan (CS) as raw materials. The hydrogels are characterized by thermal gravimetric (TG), Fourier transform infrared (FTIR), and scanning electron microscope (SEM). The rich sulfonic acid groups, carboxyl groups, hydroxyl groups, and phenolic hydroxyl groups in the hydrogel give it special properties, including excellent adhesion, electrical conductivity, sensing ability, and humidity response power generation ability. LS/CS/PAA hydrogels strongly adhere to a variety of hydrophobic or hydrophilic surfaces with excellent self-adhesive properties, such as plexiglass, paper, and plastic, and obtained adhesion strengths of up to 324.59, 196.13, and 255.76 kPa, respectively, in tests. In particular, the hydrogel showed significantly improved underwater adhesion strength in different solutions, increasing by up to 33.17% in 10 min and maintaining a stable bonding effect. In addition, LS/CS/PAA hydrogels are attractive in humidity sensing power generation with a maximum output voltage of 40.7 mV. Its good adhesion and antibacterial properties make the material more suitable for the skin and effectively inhibit bacterial growth. Its excellent ion conductivity shows high sensitivity when detecting curved body movements. In summary, this multifunctional LS/CS/PAA composite hydrogel will play an important role in many fields such as biomedicine, sensor, environmental monitoring, and energy conversion.