A biomimetic ion-crosslinked layered double hydroxide/alginate hybrid film

Natural nacre has an ordered layered arrangement of calcium carbonate platelets and ion-crosslinked protein, which enable it to achieve outstanding mechanical properties. Inspired by the relationship between structure and mechanical properties of natural nacre, we fabricate a Ca²⁺-crosslinked layered double hydroxide/alginate (LDH/ALG-Ca²⁺) hybrid film through filtration of Ca²⁺-crosslinked LDH/ALG hybrid building blocks. The LDH nanoplatelets and alginate were alternately stacked giving an ordered layered structure, in which alginate was crosslinked by Ca²⁺. The effect of LDH content and Ca²⁺ crosslinking on the microstructure and interfacial interaction of LDH/ALG-Ca²⁺ hybrid films was studied systematically. The optimized nacre-like hybrid film exhibits good flexibility and high strength (194 MPa), superior to natural nacre. The ordered layered structure and small diameter of LDH give the hybrid film a high transparency of 74-94% in the visible light wavelength range.