Electrosynthesis of Polythiophene Nanowires on Fabricated Anodic Alumina Oxide Templates

Lead (Pb) nanowire arrays were fabricated with anodic aluminum oxide (AAO) templates of 30, 100 and 300 nm in pore diameters. Through vacuum injection molding process, Pb/AAO composite was obtained, and lead sulfide (PbS) could further be synthesized after exposing to sulfur gas. AAO templates with different pore sizes were fabricated by using pure aluminum in a two-step anodization. Three types of solutions, which are 10 vol% sulfuric acid, 3 wt% oxalic acid and 1 vol% phosphoric acid, were adopted to achieve AAO of various pore sizes. Different sulfurization temperatures and time spans were applied for studying on the formation mechanism of PbS. Finally, the morphology, composition, structure and elements distribution of the as-prepared Pb and PbS nanowires were confirmed through the use of scanning electron microscopy, energy dispersive x-ray spectroscopy, element-mapping, x-ray diffraction and transmission electron microscopy analysis. The results indicated that Pb nanowires were successfully obtained after applying vacuum injection molding process with 50 kgf cm−2 hydraulic pressure, and PbS nano arrays can be formed by sulfurization at 500 °C for 5 h. Furthermore, an optical property, ultraviolet–visible (UV–Vis) absorption, was also measured. The measurement of the PbS nanowires showed that a significant quantum confinement effect made the energy gap produce a blue shift from 0.41 eV to 1.65 eV or 1.72 eV.

Anodic alumina oxide (AAO) templates with multi-branched structure were fabricated in a phosphoric acid. Atomic force microscope (AFM) was utilized to investigate the unstable growth of porous oxide film in initial stage. The morphologies of cross-section of AAO templates at different current density were also studied with FESEM. The results show that the acquired AAO templates are of multi-branched structure with large size. The diameter of pores on outer surface ranges from 150 to 220 nm, and the width of branches from 100-120 nm. This structure can be due to the unstable growth of AAO film in initial stage. Besides, the structure of AAO template is sensitive to the current density and the order degree decreases with the increase of current density: at 1.0A/dm2, most of tubes are not straight and some divided into two branches; at 2.0A/dm2, all tubes grow disorderly and form net-like structure. In this electrolyte, different types of structure of AAO templates can be acquired by adjusting current density, which may be used for the synthesis of new types of nanowires with improved mechanical properties.

A porous anodic aluminium oxide (AAO) templates were fabricated on aluminium by electrodeposition method using a two-step anodization process. The AAO templates were anodized in 0.3 M oxalic acid solution by applying a constant voltage of 40V, which was afterward treated with chemical etching process in a mixed solution of 6% phosphoric acid and 1.8% chromic acid, respectively. The temperature was kept constant in 15oC during the anodization process and the anodization time were done between 20 to 60 min. All the samples were characterized using by scanning electron microscopy (SEM) to study the surface morphology of AAO templates. It was found that the pore diameters of AAO templates can be controlled by changing the anodizing time. The influence of the electropolishing were also discussed. Highly uniform self-ordered AAO template were effectively formed from these polished foils via an anodizing process.

A mechanical pressure injection technique has been developed to fabricate uniform metallic nanowires in the pores of anodic aluminum oxide (AAO) template. The AAO template was prepared from general purity aluminum by a two-step anodization followed by heat treatment to achieve highly ordered nanochannels. The nanowires were fabricated by an injection process using a hydraulic pressure method. A mold containing the AAO template and a metal foil was placed inside a vacuum chamber and heated up to the melting temperature of the given metal using a hot plate. The hot chamber was then removed from the hot plate and pressure was applied on the melt through the sliding column of the chamber, using a hydraulic jack to impregnate the molten metal into the nanochannels of the AAO. The nanowires were found to be dense and continuous with uniform diameter throughout their length. Diffraction experiment in the transmission electron microscope revealed that individual nanowires are single crystalline. This paper will present the fabrication process of the AAO template, and the fabrication of Bi nanowires as well as their characterization conducted using SEM, TEM, XRD and DSC.

As-received multilayered Co/Cu nanowire arrays were examined by TEM, which were synthesized by pulsed DC electrodeposition using anodized aluminum oxide (AAO) templates. The multilayered Co/Cu nanowire exhibited magnetism in the perpendicular direction to the long wire axis. These nanowire can be applied to sensor array, magnetic bead(biocompatible), MRI contrast enhancing agent, ferro-fluid. Although the characterization of the multilayered Co/Cu nanowire using XRD and VSM and microstructural analysis using TEM on the bare nanowires extracted from AAO templates have been reported, interface analysis between Co and Cu phase or HREM analysis has not been reported in detail. We have prepared TEM specimen with large thin area which was appropriate for the interface analysis between Co and Cu layer without removing AAO templates using tripod polishing method. Tripod polishing proved very efficient to secure the large observable area during TEM session since the polishing angle can be precisely controlled, regardless of the mechanical strength differences in constituents. Thus we could observe not only the interface between Co and Cu layer but also the interface between the metallic layers and AAO templates. Microstructure, composition, and the concentration variation of each Co and Cu layer and the interfaces were analyzed with TEM and STEM.

Fabrication of one-dimensional ZnO nanotube and nanowire arrays with an anodic alumina oxide template via electrochemical deposition

High-density and uniform-sized FeCo alloy nanowires were prepared by electro deposition of Fe2+ and Co2+ into Anodic aluminum oxide (AAO) templates with two different diameters. These templates were fabricated with three-step anodization method. The additional anodization after the 2nd anodization step resulted in the decrease of the thickness of bottom barrier layer. It found an optimum condition to obtain a successful electrodeposition of Fe2+ and Co2+ into AAO templates. The nanowires with the diameters of 25 nm and 80 nm were homogeneously embedded in the AAO templates and their magnetic properties were strongly affected by diameters of nanowire.

Preparation of thin hexagonal highly-ordered anodic aluminum oxide (AAO) template onto silicon substrate and growth ZnO nanorod arrays by electrodeposition

Electrochemical synthesis and electrochemical behavior of highly ordered polyaniline nanofibrils through AAO templates

The Self-Organizing Anodic Aluminium Oxide(AAO) Template Is Widely Used to Construct the Nanomaterials. but the AAO Film Is Very Thin and Brittle, the AAO Templates Are Easily Been Destroied when Widening and Opening the Nanopores. the Nanorods/wires Constructed by this Template Likely Aggregate because of the High Activity of Nano-Surface at Short Range. this Paper Proposed a Novel Image of AAO Template in which Several Nanopores Combined Together to Form a Large Open Holes without Widening the Cells and Opening Barrier Layers. the Electronic Aluminium Foils with 99.99% Purity Is Anodized in Phosphoric Acid by Two-Steps, then Polarized under a Negative Voltage in the Kcl Solution. the Result of Experiment Demostrated the Possibility of the Formation Mechanism of this New Templates.

Three-dimensional (3D)-hybrid surface-enhanced Raman scattering (SERS) substrates have been achieved via simultaneous assembled silver nanoparticles (AgNPs) onto the anodic aluminum oxide (AAO) templates. The AAO templates were prepared from the UHV aluminum foil in 0.3 M oxalic acid using the two-step anodization process at 0°C. The effect of applied voltage ranging from 30 to 50 V on the porous diameter and the inter-porous distance of the AAO templates was investigated and observed with filed-emission scanning electron microscope (FE-SEM). The results showed that the porous distance and the inter-porous distance were linearly increased with the increase in the voltage potentials. To investigate the pore-size effect on the SERS activities, the AgNPs were deposited on the AAO nanoporous templates. The SERS activities of these nanostructures were demonstrated with the methylene blue (MB) as the probing molecules.

Poly(butylene adipate) (PBA) was infiltrated into the anodic alumina oxide (AAO) templates with the pore diameter of around 30, 70, and 100 nm and PBA nanotubes with different diameters were prepared. The crystallization and phase transition behavior of the obtained PBA nanotubes capped in the nanopores have been explored by using X-ray diffraction and differential scanning calorimetry. Only α-PBA crystals form in the bulk sample during nonisothermal crystallization. By contrast, predominant β-PBA crystals form in the AAO templates. The β-PBA crystals formed in the nanopores with pore diameter less than 70 nm prefer to adopt an orientation with their b-axis parallel to the long axis of the pore. During the melt recrystallization, it was found that the critical temperature (Tβ), below which pure β-crystals form, is 20 °C for bulk PBA. It drops down significantly with the pore diameter for the PBA in the AAO template. Moreover, the β-crystals in the porous template exhibit larger lattice parameters compared with the bulk crystals. By monitoring the change of β-crystals in the heating process, it was found that β-crystals in the AAO template with the pore diameter of 30 nm (D30) melt directly while the β-crystals transform to α-crystals in the template with the pore diameter of 100 nm (D100). The intensity of (020) Bragg peak of β-crystals decreases at a similar rate in both D30 and D100 but disappears at a relatively lower temperature in D30. On the other hand, the β(110) peak intensity of β-PBA crystals formed in the D100 template decreases first at slower rate before α crystals appear, and then at a faster rate once the β to α phase transition takes place.

The crystallization of poly(ε-caprolactone) (PCL) and isotactic polypropylene (iPP) infiltrated in nanoporous anodic alumina oxide (AAO) templates was reexamined to demonstrate the importance of obtaining polymer-free, clean AAO surfaces on the nucleation, size dependence of crystallization temperature (Tc), and texture. The AAO pore diameters cover a broad range from 400 to 20 nm. When the AAO templates were completely free of any residual polymer on their surfaces, differential scanning calorimetry (DSC) experiments exhibited a single crystallization peak for all the samples with different AAO pore sizes. A drastic decrease in Tc with density of domains indicated a transition from heterogeneous to homogeneous/surface nucleation. A regular decrease of Tc with pore size was observed in the low Tc regime, as a result of the volume dependence of nucleation events. The chain alignment of the two polymers infiltrated in AAO was studied by two-dimensional wide-angle X-ray scattering (WAXS). By comparing the experimental and simulated WAXS patterns, the orientation modes of the polymers were identified and compared with previous studies.

Electrodeposition of Ordered Arrays of Multilayered Cu/Ni Nanowires by Dual Bath Technique

Superparamagnetic and flexible Fe2O3 nanowire arrays were fabricated by the controlled electrostatic assembly of iron oxide nanoparticles and poly(dimethyldiallylammonium chloride) (PDADMAC) in an anodic aluminum oxide (AAO) template. The micrograph of iron oxide nanowire arrays was characterized by field emission scanning electron microscopy. The magnetic hysteresis loops obtained by a vibrating sample magnetometer confirm that the nanowire arrays have superparamagnetic properties. The filling ratio of iron oxide nanoparticles and polymers in the AAO template was affected by four factors, including the concentration of iron oxide nanoparticles, the pore diameter of the AAO template, the charge ratio of iron oxide nanoparticles and PDADMAC, and the molecular weight of polyacrylic acid. The effect of the AAO template on the diameter and length of the nanowire arrays was also analyzed. In addition, the nanowire arrays were shown to be flexible because of the presence of polymers. These nanowire arrays with superparamagnetic and flexural properties have potential applications in sensor probes.