The Self-assembly Of Air-water Interfacial Oxide Films

Fabrication of materials with various nanoarchitectures is of great scientific andtechnological importance, and self-assembly technique is an important approach to thedevelopment of nanostructured materials. The preparation of inorganic material-basedfilm using self-assembly technique has attracted intense research interest over recentyears. In this paper, a series of air-water interfacial films with ordered structure aretemplated by anion surfactants with organic metallic alkoxide precursors. X-raydiffraction, Fourier-Transform Infrared Spectra, Raman Spectra, Nuclear MagneticResonance (NMR), Thermal Gravity and Differential Thermal Analysis, Scaning ElectronMicroscope, Transmission Electron Microscope and Energy Dispersive Spectra are use tocharacterize the self-assembled films. The formation mechanism of the films is alsoinvestigated.Zirconia films composed of multiring nanodisks are self-assembled by sodium dodecylsulfonate and sodium dodecyl benzene sulfonate with gelatin as stabilizer. The interactionbetween surfactant headgroups (dimeric molecular bar) and zirconia planes is proved tobe the key to form the structure by TEM, HRTEM and NMR. Especially the formationalmechanism of the primary centre of the disk is also investigated in detail by TEM. Thethermal property of the zirconia nanodisks is also investigated.Three anionic surfactants (H⁺A^-, Na⁺A), sodium dodecyl sulfate, sodium dodecylsulfonate, sodium dodecyl benzene sulfonate and dodecyl benzene sulfonate acid, havebeen employed to template the self-assembly of titania interracial films withorganometallic compounds as precursors. All obtained films display well-orderedstructures. For the films prepared with sodium dodecyl sulfate, as a typical example, therelations between the d spacing of the lamellar structure, the critical chain length ofsurfactant molecule as well a the included angle of tilted surfactant molecule werediscussed quantitatively. By the way, further investigations have been focused on thestabilities of the surfactant template in the titania interracial films.TiO₂/ZrO₂, TiO₂/SiO₂ and ZrO₂/SiO₂ binary oxides films are self-assembled withsodium dodecyl sulfonate as template. All the films are composed of lamellar particleswith a d spacing of 3.2 nm. The particles composing TiO₂/ZrO₂ films are nano rods withthe lamellas which are perpendicular to the lengthwise position of the rods. And the particles composing ZrO₂/SiO₂ film are leaf-like slices with lamellar structure. But thelamellar structure in the films collapse after calcinations.ZnO film is self-assembled with anion surfactant (sodium dodecyl sulfonate) inalkaline solution. Lamellar structure and hexagonal structure are found respectively inZnO film prepared in the solution with different pH. It is surmised that counterion Na+ion get involved as charge compensating species and a joint of surfactant and mineralspecies.Moreover, Al₂O₃ and SiO₂ film is self-assembled with anion surfactant (sodiumdodecyl sulfonate) as template. Lamellar structure is found in Al₂O₃ film, whilemesoporous structure is observed in SiO₂ film.