title: Design of stiff, tough and stretchy hydrogel composites via nanoscale hybrid crosslinking and macroscale fiber reinforcement.
abstract: Hydrogels' applications are usually limited by their weak mechanical properties. Despite recent great progress in developing tough hydrogels, it is still challenging to achieve high values of , toughness and modulus all together in synthetic hydrogels. In this paper, we designed highly stretchable, tough, yet stiff hydrogel composites via a combination of nanoscale hybrid crosslinking and macroscale fiber reinforcement. The hydrogel composites were constructed by impregnating a 3D-printed thermoplastic-fiber mesh with a tough hydrogel crosslinked both covalently and ionically. The hydrogel composites can achieve a fracture energy of over 30,000 J m(-2), a modulus of over 6 MPa, and can be stretched over 2.8 times even in the presence of large structural defects. The enhancement of toughness in the new hydrogel composites relies on multiple pairs of toughening mechanisms which span over multiple length scales. A theoretical model is further developed to predict the toughness and modulus of the hydrogel composites and guide the design of future materials.
authors.affiliation: Department of Mechanical Engineering and Materials Science, Duke University, Durham, NC 27708, USA. zhaox@mit.edu.
authors.forename: Shaoting
authors.initials: S
authors.lastname: Lin
authors.forename: Changyong
authors.initials: C
authors.lastname: Cao
authors.forename: Qiming
authors.initials: Q
authors.lastname: Wang
authors.forename: Mark
authors.initials: M
authors.lastname: Gonzalez
authors.forename: John E
authors.initials: JE
authors.lastname: Dolbow
authors.forename: Xuanhe
authors.initials: X
authors.lastname: Zhao