A pseudo‐Double‐Network Hydrogel Built upon Layered Double Hydroxides with Self‐Strengthening Properties

While great achievements have been made in the development of mechanically robust nanocomposite hydrogels, incorporating multiple interactions on the bases of two demensional inorganic cross‐linkers to construct self‐strengthening hydrogels has rarely been investigated. To this end, we propose here a new method for the coupling the dynamic covalent bonds and non‐covalent interactions within a pseudo double‐network system. The pseudo first network, formed through the Schiff Base reation between Tris‐modified layered double hydroxides (Tris−LDHs) and oxidized dextran (ODex), is linked to the second network built upon non‐covalent interactions between Tris−LDHs and poly(acrylamide‐co‐2‐acrylamido‐2‐methyl−propanesulfonate) (p‐(AM‐co‐AMPS). The swelling and mechanical properties of the resulting hydrogels have been investigated as a function of the ODex and AMPS contents. The as‐prepared hydrogel can swell to 420 times of its original size and retain more than 99.9 wt.% of water. Mechanical tests show that the hydrogel can bear 90 % of compression and is able to be stretched to near 30 times of its original length. Cyclic tensile tests reveal that the hydrogels are capable of self‐strengthening after mechanical training. The unique energy dissipation mechanism based on the dynamic covalent and non‐covalent interactions is considered to be responsible for the outstanding swelling and mechanical performances. Layered double hydroxide (LDH) hydrogels, possessing a pseudo‐double‐network, have been constructed on the basis of dynamic covalent bonds, electrostatic interactions and hydrogen bonding. The as‐prepared nanocomposite hydrogels can retain more than 99 wt.% of water and exhibit a self‐strengthening phenomenon, which originates from the inherent dynamic interactions, after mechanical training.