Crystallization-Driven Supramolecular Gelation of Poly(vinyl alcohol) by a Small Catechol Derivative

Abstract

Catechol-containing molecules have been recognized as versatile building blocks for polymer structures with tailormade functional properties. While catechol chemistry via metal− ligand coordination, boronate complexation, and oxidation-driven covalent bonds has been well examined in the past, the hydrogen bonding ability of these intriguing molecules has been dismissed. In this research, we investigated the gelation of poly(vinyl alcohol) (PVA) triggered by the crystallization of a 3,4-dihydroxy-catechol in water. Strong hydrogen bond interactions between PVA and catechol groups afforded supramolecular hydrogels with nearcovalent elastic moduli, yet dynamic, exhibiting reversible gel-tosol phase transitions around 50−60 °C. We studied the impact of the catechol derivative concentration on the gelation kinetics and physicochemical properties of these dynamic materials. Isothermal experiments revealed that heterogeneous crystallization governs the gelation kinetics. Moreover, because of the quasi-permanent cross-links within the supramolecular polymer network, these hydrogels benefit from ultrastretchability (∼600%) and high toughness (900 kJ•m −3 ). Our gelation approach is expected to expand the toolbox of catechol chemistry, opening up new avenues in designing dynamic soft materials with facile control over the phase transition, mechanics, and viscoelastic properties.

Biphasic Approach for the Synthesis of Au Nanoparticles via Diffusional Release of Gallic Acid from Supramolecular Hydrogels to Aqueous Solutions: Implications for Biomedical Applications

“…The SEM images of these PVA-GA hydrogels show that the concentration of GA in the polymer network changes the morphology (Figure B). An increase in the GA concentration decreases the interconnection in the structure of the hydrogel, making it a fragile material featuring a globular microstructure, as previously observed in this type of supramolecular network. , …”

“…An increase in the GA concentration decreases the interconnection in the structure of the hydrogel, making it a fragile material featuring a globular microstructure, as previously observed in this type of supramolecular network. 33,39 Release Behavior of GA from PVA-GA Hydrogel and Kinetics of Au NP Formation. The release profile of the GA in the different PVA-GA hydrogels analyzed before was studied for simplicity in a biphasic system of PVA-GA/water.…”

“…Moreover, PCs have the exciting property of forming supramolecular interactions with specific polymers. − In this sense, the formation of supramolecular hydrogels from poly­(vinyl alcohol) (PVA) and GA has been previously described. − These materials can be prepared by a hot-dissolution/cooling method, resulting in thermoreversible supramolecular networks with outstanding viscoelastic and mechanical qualities by dynamic interactions between the polymer and GA. The concentration of GA could control the gel–sol phase transition of these hydrogels, the degree of hydrolysis of PVA, and even the PVA/GA molar ratio.…”

Semi-solid electrodes based on injectable hydrogel electrolytes for shape-conformable batteries

“…Recently, small-sized polyphenols such as gallic acid (GA), protocatechuic acid, and pyrogallol, among others, have been demonstrated to be promising for supramolecular hydrogel chemistry. 14,15 Interestingly, poly(vinyl alcohol) (PVA):GA hydrogels feature fast gelation kinetics, shear-thinning behaviour, and low gel-to-sol phase transition temperatures (70 1C), rendering them innovative options for semi-solid electrodes. 16 In this work, PVA:GA gels are used as electrolytes for the fabrication of shape-conformable batteries.…”

Adhesive, self-healable and biodegradable dopamine modified PVA films for sustainable electronics

“…License: CC BY-NC-ND 4.0 [26] clickable coupling reactions [27] or multiplex supramolecular interactions. [28] The use of expensive raw materials or tedious preparation methods limited their practical applications.…”