An efficient strategy to design and construct high‐strength and fluorescence poly(vinyl alcohol) hydrogels via freeze–Thaw cycles

Abstract

Fluorescent hydrogels are soft materials that can emit light under certain conditions, which makes them attractive for biomedical and engineering applications. Nevertheless, one of the major challenges in developing fluorescent hydrogels is their low mechanical properties. To overcome this challenge, we have developed an efficient method for preparing high‐strength and fluorescence hydrogels via freeze–thaw cycles. This approach offers a promising solution to enhance the mechanical properties of fluorescent hydrogels, which could broaden their applications in various fields. We used polyvinyl alcohol (PVA) as the main component and added 2,4,6‐tri(4‐aminophenyl) triazine (TAPT) as a rigid fluorescent substance. We find that these hydrogels have higher strength than conventional PVA hydrogels. These hydrogels exhibit strong fluorescence. Hydrogen bonds and π‐π stacking between NH2 and PVA construct the network structure. The composite hydrogel has significant mechanical properties, with a maximum tensile strength of 44.7 MPa, maximum elongation at break of 310.1% and Young's modulus of 138.5 MPa. Compared with the PVA hydrogel, the tensile strength and elongation at break of the hydrogel with the addition of 2% TAPT are increased by 292.6% and 153.0%, respectively. TAPT molecules are bound to the inside of the gel network, which makes the composite hydrogels have strong fluorescence. These hydrogels with high strength and fluorescence have a wide range of applications in flexible electronics and information displays.

Hybrid Encoding Strategy of Multi-Stimulus Response Aggregation-Induced Emission Hydrogels for Advanced Information Encryption and Safety

“…Moreover, the PTO-1.5 hydrogel with a thickness of ≈2 mm and width of ≈15 mm is capable of withstanding a weight of ≈300 g without any damage, demonstrating its high load-bearing ability. By increasing the content of TPE-4OH, the number of hydrogen bonds formed with PVA could be increased. , The introduction of a benzene ring forms the π–π stacking effect, increases intermolecular forces, and results in a conjugated electron transfer effect. , This enhances the interaction and tensile strength of gels. Yet to a certain extent, the greater addition of TPE-4OH can cause the intermolecular distance of the hydrogels to decrease, thereby increasing the cohesion of the hydrogels.…”

“…25,26 The introduction of a benzene ring forms the π−π stacking effect, increases intermolecular forces, and results in a conjugated electron transfer effect. 27,28 distance of the hydrogels to decrease, thereby increasing the cohesion of the hydrogels. This could reduce the strength of the hydrogels.…”

“…25,26 The introduction of a benzene ring forms the π−π stacking effect, increases intermolecular forces, and results in a conjugated electron transfer effect. 27,28 This enhances the interaction and tensile strength of gels. Yet to a certain extent, the greater addition of TPE-4OH can cause the intermolecular distance of the hydrogels to decrease, thereby increasing the cohesion of the hydrogels.…”

Fabricating of poly(vinyl alcohol)/halloysite nanotubes/gelatin composite sponges with enhanced mechanical properties and rapid water absorption speed

“…1 It can be used in vascular cell culture, vascular implantation, and corneal implants [2][3][4] as a biomedical material. 5,6 In particular, PVA has been applied to repair injured soft tissues such as cartilage, liver, or kidney tissue 7 due to its benefits of nontoxicity, [8][9][10] flexibility, 11 biocompatibility, and biodegradability. 12,13 Nevertheless, the practical application of PVA is restricted by its inadequate mechanical properties, insufficient water absorption, and slow water absorption rate, which limit the practical application of PVA.…”