Tough Soft Wet Adhesion

Tough bonding of hydrogels to diverse non-porous surfaces

Hyunwoo Yuk, Teng Zhang,Shaoting Lin, German Alberto Parada & Xuanhe Zhao

Nature Materials (2015) doi:10.1038/nmat4463

In many animals, the bonding of tendon and cartilage to bone is extremely tough (for example, interfacial toughness ~800 J m−2), 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.

www.nature.com/nmat/journal/vaop/ncurrent/full/nmat4463.html