A Multifunctional, Self-Healing, Self-Adhesive, and Conductive Sodium Alginate/Poly(vinyl alcohol) Composite Hydrogel as a Flexible Strain Sensor

Abstract

Hydrogel-based wearable devices have attracted tremendous interest due to their potential applications in electronic skins, soft robotics, and sensors. However, it is still a challenge for hydrogel-based wearable devices to be integrated with high conductivity, a self-healing ability, remoldability, self-adhesiveness, good mechanical strength and high stretchability, good biocompatibility, and stimulus-responsiveness. Herein, multifunctional conductive composite hydrogels were fabricated by a simple one-pot method based on poly­(vinyl alcohol) (PVA), sodium alginate (SA), and tannic acid (TA) using borax as a cross-linker. The composite hydrogel network was built by borate ester bonds and hydrogen bonds. The obtained hydrogel exhibited pH- and sugar-responsiveness, high stretchability (780% strain), and fast self-healing performance with healing efficiency (HE) as high as 93.56% without any external stimulus. Additionally, the hydrogel displayed considerable conductive behavior and stable changes of resistance with high sensitivity (gauge factor (GF) = 15.98 at a strain of 780%). The hydrogel was further applied as a strain sensor for monitoring large and tiny human motions with durable stability. Significantly, the healed hydrogel also showed good sensing behavior. This work broadens the avenue for the design and preparation of biocompatible polymer-based hydrogels to promote the application of hydrogel sensors with comfortable wearing feel and high sensitivity.

Injectable Nanocomposite Hydrogels for Cancer Therapy

“…[ 30 ] The multifunctional conductive composite hydrogel has high biological tensile properties, good electrical conductivity, stable resistance, good sensitivity, fast self‐healing properties, and can respond to a variety of stimuli. [ 40 ] It has very good application prospects in biosensing. In general, composite hydrogels combine the advantages of natural polymers and synthetic hydrogels, and have good development prospects in the field of biomedicine.…”

“…It is worth noting that the self‐healing hydrogel also shows good sensing behavior after healing. [ 40 ] Lin et al. established a thrombin aptamer 1 functionalized magnetic hydrogel based on the physical interaction between sodium alginate and calcium ions, and used it as a “signal‐on” chemiluminescence biosensor for thrombin detection.…”

Synthesis of micrometer-sized poly(vinyl acetate) particles through microsuspension iodine transfer polymerization: effect of iodine species in a water medium

“…As one of its main applications, the hydrolysis of PVAc produces poly(vinyl alcohol) (PVA), which is attractive in the chemistry and biology fields because of fascinating properties such as low toxicity, high hydrophilicity, adhesivity, biodegradation, and biocompatibility. 15,16 The performance of PVA or PVA-based materials is strongly influenced by their molecular weight and molecular weight distribution. Therefore, the synthesis of PVAc with desirable molecular weight and molecular weight distribution is of great significance for further development of its potential applications.…”

Bio-based, self-adhesive, and self-healing ionogel with excellent mechanical properties for flexible strain sensor

“…Meanwhile, due to the shortage of fossil resources and environmental degradation, scientists are gradually turning their interest to renewable and eco-friendly biomass materials. Natural polymers such as cellulose, [7][8][9][10][11][12] sodium alginate, [13][14][15][16] dextran 17,18 and chitosan 19,20 have been widely used in the preparation of polymer products to replace synthetic polymers. Wang et al 12 fabricated an ionogel by cellulose and ionic liquid, which had obvious advantages over the existing equivalent products in terms of mechanical and electrical conductivity.…”