Enhancing the Mechanical Properties of Hydrogels Based on Photo-Polymerizable π-Conjugated Polymers

A common strategy to enhance the mechanical properties of hydrogels is the incorporation of covalent or noncovalent cross-linking mechanisms. The choice of suitable cross-linking materials and simplicity of the process are critical factors. In this study, vesicle-like photopolymerizable diacetylene (DA) assemblies were integrated into poly(vinyl alcohol) (PVA) hydrogel. Upon UV-irradiation, the mechanical properties of PVA hydrogel were gradually enhanced, accompanied by the formation of polydiacetylene (PDA) backbones. Compared with the pristine hydrogel, the tensile strength and Young’s modulus of PDA–PVA hydrogel increased 5.5- and 3.2-fold, respectively, owing to the combined effects of photopolymerization and hydrogen bonding between PDA vesicles and PVA chains. Moreover, the resulting hydrogel exhibited excellent energy dissipation capacity. The strategy proposed in this study, introducing photopolymerizable DA assemblies into hydrogels provides a promising new approach for enhancing mechanical properties of hydrogels.