Hydrogels totally from inorganic nanosheets and water with mechanical robustness, self-healing, controlled lubrication and anti-corrosion

Synthetic hydrogels with attractive mechanical strength and self-healing are particular appealing, in light of their significance and prospects in industrial, engineering and biomimetic fields. Fabricating various mechanically robust and self-healable hydrogels have achieved some successes in using strong covalently bonded organic polymers as building blocks. However, creation of such soft materials entirely building on rigid inorganic components remains greatly challenging, because inorganic materials are usually poorly flexible and processable. In this study, mechanical robustness and self-recovery are successfully integrated into a single-component colloidal hydrogel system of aluminium hydroxide nanosheets (AHNSs). The inorganic colloidal hydrogel gains an excellent elasticity and stiffness, as indicated by its elastic modulus >10 MPa, due to the use of tough AHNS gelator and the formation of long-range ordered lamellar architectures consisting of self-assembled side-to-side or interlaced-stacking NS superstructures. The metastability in internal gel network endows the hydrogel a self-healing efficiency of larger than 100%. The AHNS hydrogel has been demonstrated to be effectively lubricative and anti-corrosive. Its mechanical, tribological and anti-corrosion properties can be optimized by tuning its internal NS configuration and salt content. Our study may be a potent replenishment to the scope of materials science and may provide new insights into nanotechnology, colloidal chemistry, green tribology and mechanical engineering.