title: Tough bonding of hydrogels to diverse non-porous surfaces.
abstract: In many animals, the bonding of tendon and cartilage to bone is extremely tough (for example, interfacial toughness ∼800 J m(-2); refs ,), yet such tough interfaces have not been achieved between synthetic hydrogels and non-porous surfaces of engineered solids. Here, we report a strategy to design tough transparent and conductive bonding of synthetic hydrogels containing 90% water to non-porous surfaces of diverse solids, including glass, silicon, ceramics, titanium and aluminium. The design strategy is to anchor the long-chain polymer networks of tough hydrogels covalently to non-porous solid surfaces, which can be achieved by the silanation of such surfaces. Compared with physical interactions, the chemical anchorage results in a higher intrinsic work of adhesion and in significant energy dissipation of bulk hydrogel during detachment, which lead to interfacial toughness values over 1,000 J m(-2). We also demonstrate applications of robust hydrogel-solid hybrids, including hydrogel superglues, mechanically protective hydrogel coatings, hydrogel joints for robotic structures and robust hydrogel-metal conductors.
authors.affiliation: Soft Active Materials Laboratory, Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Hyunwoo
authors.identifier: http://orcid.org/0000-0003-1710-9750
authors.initials: H
authors.lastname: Yuk
authors.affiliation: Soft Active Materials Laboratory, Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Teng
authors.initials: T
authors.lastname: Zhang
authors.affiliation: Soft Active Materials Laboratory, Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Shaoting
authors.initials: S
authors.lastname: Lin
authors.affiliation: Soft Active Materials Laboratory, Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.|Department of Chemical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: German Alberto
authors.initials: GA
authors.lastname: Parada
authors.affiliation: Soft Active Materials Laboratory, Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.|Department of Civil and Environmental Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Xuanhe
authors.initials: X
authors.lastname: Zhao
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D001842:Bone and Bones; D002356:Cartilage; D002616:Chemical Engineering; D020100:Hydrogels / Q000737:chemistry*; D008422:Materials Testing; D013499:Surface Properties; D013710:Tendons
chemical_list: D020100:Hydrogels