Freeze-resistant, rapidly polymerizable, ionic conductive hydrogel induced by Deep Eutectic Solvent (DES) after lignocellulose pretreatment for flexible sensors

Qiao

ACS Appl. Polym. Mater.

et al. 2023

In this study, gelatin hydrogels with excellent anti-freezing properties were prepared by simply immersing the initial hydrogels in a deep eutectic solvent (DES) aqueous solution. The formation of ice crystals in hydrogels is greatly hindered by introduction of the DES even at very low temperatures. The hydrogels still remain mechanically flexible even at −80 °C. In addition, the DES could facilitate the protein chain bundling, resulting in the formation of triple helices and thus improving the mechanical properties of gelatin hydrogels. Furthermore, the hydrogels could be stored for a long time with slight water loss, thus showing good water retention performance.

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Fabrication and Properties of Anti-freezing Gelatin Hydrogels Based on a Deep Eutectic Solvent

Qiao

ACS Appl. Polym. Mater.

et al. 2023

Chemistry An Asian Journal

“…In addition, the conductivity of the hydrogel sensor is 10 mS/cm, and the relative resistance change can be obtained within 441 ms, showing excellent sensitivity and electrical sensing ability (Figure 11b). [116] Finally, Table 1 summarizes the performance of PVA/plant-based biomass conductive hydrogels as wearable and flexible sensors.…”

Section: Pva/lignin Sensormentioning

confidence: 99%

Plant‐based Biomass/Polyvinyl Alcohol Gels for Flexible Sensors

Cheng

et al. 2023

Flexible sensors show great application potential in wearable electronics, human‐computer interaction, medical health, bionic electronic skin and other fields. Compared with rigid sensors, hydrogel‐based devices are more flexible and biocompatible and can easily fit the skin or be implanted into the body, making them more advantageous in the field of flexible electronics. In all designs, polyvinyl alcohol (PVA) series hydrogels exhibit high mechanical strength, excellent sensitivity and fatigue resistance, which make them promising candidates for flexible electronic sensing devices. This paper has reviewed the latest progress of PVA/plant‐based biomass hydrogels in the construction of flexible sensor applications. We first briefly introduced representative plant biomass materials, including sodium alginate, phytic acid, starch, cellulose and lignin, and summarized their unique physical and chemical properties. After that, the design principles and performance indicators of hydrogel sensors are highlighted, and representative examples of PVA/plant‐based biomass hydrogel applications in wearable electronics are illustrated. Finally, the future research is briefly prospected. We hope it can promote the research of novel green flexible sensors based on PVA/biomass hydrogel.

ACS Sustainable Chem. Eng.

“…24−26 Gels fabricated using deep eutectic solvents (DES) are more economical, biocompatible, resistant to extreme temperatures, and less toxic than traditional hydrogels and ionic liquids. 27 Gels of DESs were currently investigated in sensors, 28 capacitors, 29 and batteries. 30 Despite the high safety, better electrochemical stability, and low cost, gels made of DES still suffer from low ionic conductivity.…”

Section: ■ Introductionmentioning

confidence: 99%

“…To enable the practical application of flexible hydrogel-based sensors, the antifreezing and antidrying ability should be carefully taken into consideration. Typically, by fabricating the “ionic liquid-water” hybrid gels, the formation of ice crystals can be efficiently inhibited, , whereas ionogels made of ionic liquids (ILs) are not biocompatible, of high cost, or even toxic. − Gels fabricated using deep eutectic solvents (DES) are more economical, biocompatible, resistant to extreme temperatures, and less toxic than traditional hydrogels and ionic liquids . Gels of DESs were currently investigated in sensors, capacitors, and batteries .…”

Section: Introductionmentioning

confidence: 99%

“Deep Eutectic Solvent-in-Water” Hydrogels Enable High-Performance Flexible Strain Sensors for Electronic Skin with a Wide Operating Temperature Range

Wang

Xing

et al. 2023

Conductive hydrogels have become one of the hot topics in flexible strain sensors owing to excellent biocompatibility, attractive mechanical flexibilities, and conductive properties. However, the time-consuming preparation of hydrogels and their unsuitable properties limit their application in low-temperature environment and high temperatures. Here, a new class of “deep eutectic solvent-in-water” hydrogels (DIWHs) is reported for the first time through a one-step gelation process in situ without solvent displacement, fabricated by combining a hydrogel with deep eutectic solvent (DES). The DIWH is constructed using a dynamic oxidation and coordination system composed of sodium lignosulfonate (Ls) and Fe3+. The effect of DES and the optimal mass ratio of water and DES on the hydrogel properties was synthetically investigated. The addition of DES not only shortens the polymerization time to 8 s and enhances the mechanical properties of the hydrogel but also provides some unique properties. For example, the addition of DES gives the gels greater self-healing ability and antibacterial properties. When the mass ratio of water to DES was 1:3, excellent antifreezing and antidrying properties were imparted to the gel, and the elasticity of the hydrogel was maintained even at −80 °C or stored at 60 °C for 7 days. Furthermore, the hydrogel exhibited strong interfacial adhesion to natural and synthetic materials (up to 60 kPa on glass) due to the presence of Ls with a catechol structure. In conclusion, this work stimulates more interest in the sustainable and high-value utilization of DES and fully demonstrates the advantages of this new easy-to-prepare coacervation gel for sensing.