Solvothermal Ion Exchange of Aliphatic Dicarboxylates into the Gallery Space of Layered Double Hydroxides Immobilized on Si Substrates

Highly ordered Mg/Al-based layered double hydroxide (LDH) nanocrystals on Si substrates were successfully obtained by ultrasonic treatment in organic solvents. LDHs intercalated with aliphatic (alpha),(omega)dicarboxylate were prepared through anion exchange by solvothermal treatment at around 100 C. Binary solvent mixtures of alcohol and toluene prevent dissolution of the LDH and preserve the layered crystal structure of the LDH during the anion-exchange reaction. Atomic force microscopy results present conservation of lateral positions and morphologies of the LDH crystals on Si before and after anion exchange. The interlayer spacings of LDH crystals intercalated with dicarboxylates vary directly with the chain length of the dicarboxylates, and reaction stepwise anion exchanges are possible. The results gave an original example of the direct measurement of the anisotropic nanomorphological change of the selected LDH crystals in the intercalation reaction, which opens a wide range of applications.