AMPHIPHILIC TEMPLATING OF MESOSTRUCTURED ZIRCONIUM-OXIDE

The synthesis of zirconium oxide with a mesostructured framework (Zr-T MS) has been achieved through the use of amphiphilic compounds with a variety of headgroups (anionic and nonionic) and tail group chain leng ths (1-18 carbons). Anionic surfactants with phosphate, carboxylate, s ulfate, and sulfonate headgroups led to disordered hexagonal and/or la yered phases. Mesoporous zirconia with high surface areas could be obt ained through calcination of materials templated with phosphate amphip hiles; the phosphate headgroups remained on the pore walls and appeare d necessary for thermal stability. Nonionic amine amphiphiles have bee n found to lead to less ordered zirconia mesostructures, due to the we ak interaction with the zirconium n-propoxide precursor. The chain-len gth-independent templating ability of the amphiphiles and ex situ P-31 MAS NMR of dodecyl phosphate (before and after incorporation into Zr- TMS) supported a method of formation involving covalent-bond interacti ons between the headgroup and the inorganic precursor.