An effect of alginate on the stability of LDH nanosheets in aqueous solution and preparation of alginate/LDH nanocomposites

• Alginate can stabilize LDH nanosheets preferably in an aqueous solution.
• Alginate/LDH nanocomposites were prepared by delamination and restacking of LDH.
• LDH enhanced the thermal stability and mechanical properties of alginate.

Nanosheets under 10 nm in thickness are obtained by exfoliating layered double hydroxide (LDH) in formamide. The LDH nanosheets are dispersed and stabilized in an alginate aqueous solution after removing formamide by water washing and ultracentrifugation. During the water washing stage LDH nanosheets can be prevented from restacking by electrostatic stabilization of the surface of LDH sheets through the adsorption of alginate. Alginate/LDH nanocomposites can be prepared by drying the dispersion, and sandwich-like structures in the nanocomposites are formed with two alginate layers contained between two LDH sheets. LDH nanosheets in the dried alginate/LDH nanocomposites can be re-dispersed in water. The thermal stability of alginate in the nanocomposite is increased by LDH. Alginate membranes containing this layered nanocomposite can be prepared. The addition of LDH into the alginate matrix leads to an increase in the mechanical properties of the nanocomposite.