Amphiphilic Templating of Mesostructured Zirconium Oxide

The synthesis of zirconium oxide with a mesostructured framework (Zr-TMS) has been achieved through the use of amphiphilic compounds with a variety of headgroups (anionic and nonionic) and tail group chain lengths (1-18 carbons). Anionic surfactants with phosphate, carboxylate, sulfate, and sulfonate headgroups led to disordered hexagonal and/ or layered phases. Mesoporous zirconia with high surface areas could be obtained through calcination of materials templated with phosphate amphiphiles; the phosphate headgroups remained on the pore walls and appeared necessary for thermal stability. Nonionic amine amphiphiles have been found to lead to less ordered zirconia mesostructures, due to the weak interaction with the zirconium n-propoxide precursor. The chain-length-independent templating ability of the amphiphiles and ex situ ³¹P MAS NMR of dodecyl phosphate (before and after incorporation into Zr-TMS) supported a method of formation involving covalent-bond interactions between the headgroup and the inorganic precursor.