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A new dual nanocomposite hydrogel with excellent mechanical properties have been developed by sol-gel reaction of vinyl triethoxysilane (VTES) and in situ radical polymerization of acrylamide (AM) and VTES in the dispersion of Bentonite (Bent). Unlike conventional cationic surfactant intercalators, VTES was used as both an intercalator and a crosslinker. Good intercalation and exfoliation were confirmed by transmission electron microscopy (TEM) and X-ray diffraction (XRD) results. The covalent interaction between Bent and silica by condensation of VTES was confirmed by Fourier transform infrared spectroscopy (FTIR) and 29 Si solid-state NMR. The compressive stress of the gel reached up to 4.65 MPa with ha huge fracture energy of 6285.59 J m − 2 (water content of 85 wt%). The gel showed a high cross-linking density of 77.17 mol m − 3 by dynamic viscoelastic measurement. The compressive stress increased to above 25 MPa when the water content decreased to 50 wt%. In the tough nanocomposite hydrogel, the nano-scaled SiO 2 was covalently bonded to intercalated or exfoliated Bent and polymer chains, and thus greatly improved the mechanical properties of the gel [ABSTRACT FROM AUTHOR]