Direct observation of the cell material comprising porous anodic films formed on aluminium

The Effects of Acid and Water in the Formation of Anodic Alumina: DFT and Experiment Study

The DFT method is employed to study the adsorption and reaction behaviors of HC2O4−, H2PO4−, HSO4− and H2O on neutral and anodic aluminum slabs. With the exception of adsorption, the three acid radicals can successively take the two H atoms from the adsorbed H2O on the anodic aluminum slabs, which is the key step of the formation of anodic alumina. The dehydrogenation reaction is dominated by the Coulombic interaction of O and H, respectively belonging to acid radicals and the adsorbed H2O or OH, rather than by the interaction of electronic orbits located on the two kinds of atoms. The experiment of anodic polarization of aluminum verifies the calculation result well.

Determination of the field strength and realization of the high-field anodization of aluminum

The electric field strength during aluminum anodization was clarified, and this work can shed some light on the self-ordering mechanism of porous anodic alumina.

Extremely high aspect ratio alumina transmission nanomasks: their fabrication and characterization using electron microscopy

Free standing, nanoporous alumina templates were fabricated as transmission masks from aluminium using a two-step anodization process followed by acid etching. The resulting membrane comprises self-ordered, periodic arrays of non-connecting circular channels which can be prepared with pore diameters <100 nm and with minimal occlusion. Aspect ratios greater than 300:1 were measured directly using electron transmission and the channels were shown to be highly aligned (angular) over membrane thicknesses of tens of microns. Also evident is some local order associated with both azimuthal and angular domain structure giving rise to local channel tilt which has not previously been reported. Transmission electron microscopy has been shown to be an important characterization tool for these nanomasks as the channels are transparent to electrons, providing a means of directly measuring their thickness and aspect ratio. Expressions for determining their thickness and aspect ratio are also presented and evaluated in this work. These membranes are well suited for use as nanotemplates in transmission lithography applications including ion implantation and ion or electron beam collimation.