Beyond reinforcement: harnessing network entanglements for multifunctional hydrogel design

Hydrogel network entanglements play an important role in enhancing mechanical strength and network stability without reliance on permanent chemical crosslinks. Despite their significance, entanglements are often marginalized as secondary to chemical crosslinks. They are primarily assumed to contribute only to mechanical reinforcement, while their contributions to network functionality remain largely under-recognized. However, these topological interlocks fundamentally regulate polymer mobility, energy dissipation, and dynamic network responsiveness, generating a range of functionalities in hydrogel materials, such as self-healing, adhesion, weldability, stimuli responsiveness, and processability. This review focuses on polymer chain entanglements as a fundamental architectural feature that drives such multifunctionality in hydrogels. Hydrogel entanglements, often overlooked relative to chemical crosslinks, enhance strength and stability while enabling dynamic functions such as self-healing, adhesion, and processability. Here, the authors focus on polymer chain entanglements as a fundamental structural feature driving hydrogel multifunctionality.