An Amphiphilic Entangled Network Design Towards Ultratough Hydrogels.

Hydrogels find important roles in biomedicine, wearable electronics and soft robotics, but their mechanical properties are often unsatisfactory. Conventional tough hydrogel designs are based on hydrophilic networks with sacrificial bonds, while incorporation of hydrophobic polymers into hydrogels is less well understood. In this work, we demonstrate a hydrogel toughening strategy by introducing a hydrophobic polymer as reinforcement. Semicrystalline hydrophobic polymer chains are "woven" into a hydrophilic network via entropy-driven miscibility. In-situ formed sub-micrometer crystallites stiffen the network, while entanglements between hydrophobic polymer and hydrophilic network enable large deformation before failure. The hydrogels are stiff, tough and durable at high swelling ratios of 6-10, and the mechanical property are tunable. Moreover, they could effectively encapsulate both hydrophobic and hydrophilic molecules. This article is protected by copyright. All rights reserved.