Mechanically Robust, Tough, and Self‐Recoverable Hydrogels with Molecularly Engineered Fully Flexible Crosslinking Structure

Abstract

How to reasonably fabricate polymer network for high performance hydrogels is a critical issue but remains a challenge. This work reports an approach to high performance hydrogels by molecularly engineering fully flexible crosslinking (ffC) network. A model network cross‐linked by fully flexible crosslinking points of triblock copolymer micelles and ionic interactions is fabricated. Due to the unique structure, the resulting ffC hydrogels are mechanically robust, tough, and self‐recoverable. For as‐prepared ffC hydrogels, a tensile stress more than 3.5 MPa can be achieved and the energy dissipation can reach up to 6.61 MJ m −3 at the tensile strain of 125%. Moreover, ffC hydrogels fabricated under constant strain can achieve an energy dissipation ability up to 11.63 MJ m −3 at the tensile strain of 100% and a tensile stress of 17.57 MPa. Based on these results, a dynamic molecular mechanism in the ffC hydrogel network under tensile deformation is proposed. The high performances of the ffC hydrogels can be possibly attributed to the sequential breakage and energy dissipation of the flexible crosslinking points and the easily accessible polymer chain orientation during tensile deformation. image