Tough hybrid hydrogels based on simultaneous dual in situ sol–gel technique and radical polymerization

Abstract

A tough hybrid hydrogel has been developed by dual in situ sol–gel reaction of γ‐ethacryloxypropyltrimethoxysilane (MPTMS) and tetrabutyl titanate, as well as in situ radical polymerization of acrylamide (AM) and MPTMS. In this hydrogel, covalently bonded SiO2 and TiO2 nanoparticles were used as inorganic filler and multifunctional crosslinker. Nano‐TiO2 was bonded onto the surface of SiO2 by forming TiOSi bonds and SiO2 bonded with polymer chains by the formation of COSi bonds, which were confirmed by Fourier transform infrared and X‐ray photoelectron spectroscopy technology. Transmission electron microscopy images revealed that SiO2 and TiO2 tended to construct a distinct rod‐like structure in poly(AM) matrix. This specific microstructure enhanced the mechanical properties of hydrogel. The compressive stress of the gel reached up to 9.49 MPa, and the compressive fracture energy was as high as 5307.73 J m−2. This strategy provided a probable method for the preparation of tough soft materials with potential applications in chemical machinery and actuators. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47742.