Ultrathin layered double hydroxide nanosheets for the production of multifunctional acid-free papers with enhanced durability

Paper—an essential carrier for information dissemination and the inheritance of civilization—holds significant importance in both daily life and specific applications. Nevertheless, the acidification of paper reduces its mechanical strength, restricts its functionality, and considerably shortens its service life. In this research, a handmade acid-free paper (HMAP) with an initial pH of 7–8 was prepared by incorporating ultrathin magnesium–aluminum layered double hydroxide (LDH) nanosheets as a filler in the paper preparation process. The Mg–Al LDH nanosheets, with an average layer thickness of about 8 nm, were synthesized via a one-step surfactant-assisted hydrothermal method. Simultaneously, the HMAP exhibits the advantages of long service life and acid resistance after a prolonged accelerated aging experiment (two months), maintaining a pH above 6. Additionally, the HMAP also possesses potential application value in some domains such as flame retardancy and adsorption. This work substantiates the feasibility of ultrathin LDH as a paper filler and broadens its prospects in the preparation of acid-free long-life paper.