Preparation of highly oriented organic-LDH hybrid films by combining the decarbonation, anion-exchange, and delamination processes

For the preparation of highly-oriented thin films of organic-LDHs (layered double hydroxides) with Mg/Al = 2 and 3, highly-oriented LDH films with anion-exchangeability were prepared (a) by casting a CO32- LDH water suspension onto a glass slide, followed by decarbonation in an HCl-NaCl solution and anion-exchange to ClO4-LDH, and (b) by casting delaminated ClO4-LDH in formamide (FA) onto a glass slide. These ClO4-LDH films formed on glass substrates were further anion-exchanged by p-toluenesulfonate anions (Tos(-)) to produce organic LDH hybrid films with retention of their orientation and transparency. The direct delamination of Tos(-)LDH in FA was also successfully conducted, and a highly-oriented Tos(-)LDH hybrid film was obtained by casting the colloidal Tos(-)LDH solution on a glass slide. These three procedures offered well-oriented organic-LDH films, and especially, the process involving the delamination treatments gave more dense and transparent films.