Understanding the thermal conductivity variations in nanoporous anodic aluminum oxide

Abstract

Anodic porous alumina (AAO) templates, also known as nanoporous anodic alumina (NAA) platforms or membranes, are widely used in nanoscience and nanotechnology. During fabrication, characterization, or device performance they are...

Revisiting anodic alumina templates: from fabrication to applications

“…Some works reviewing this topic could be found in references [238][239][240] . The use of nanoporous alumina structures as templates to grow different materials inside them presents several advantages over other kinds of templates, such as the diameter sizes possible to achieve, in the range of nanometers, combined with straight pore Please do not adjust margins Please do not adjust margins lengths in the range of microns, the low cost and large area of ordered nano-cylinder arrays that can be provided, the thermal stability in a wide range of temperatures, without losing the porous structure even after treatments over 1000 °C 241,242 . Depending on the template-assisted growth mechanism used for the material, the original porous alumina can be used with the barrier layer and backing aluminum (for instance, for polymer infiltration, atomic layer deposition, etc.)…”

“…Then, as we will see through this review, AAOs appear as the most suitable platforms for a great number of applications, either as porous materials themselves, either as templates for the fabrication of a variety of nanostructured architectures. They provide thermal stability of the structures, even over 1000ºC 77 , large areas of a high density of pores, good control over the pore diameter (which can range from tens to hundreds of nm), great control over the structural parameters of 3D structures, and a large aspect ratio with a cost-effective, easily scalable method, and therefore, are widely used and provide an active field of research.…”

Recent Advances in Nanoporous Anodic Alumina: Principles, Engineering, and Applications

“…This intake is an intrinsic factor partially responsible for the variations in the thermal conductivity of NAA reported in the literature. Recently, an attempt to systematize the observed effect was reported by Vera-Londono et al [ 35 ]. It was established that thermal conductivity depends on the presence of ionic impurities—thus the electrolyte of choice—along with water built in the structure, and the crystalline form.…”

Dependence of the Magnetization Process on the Thickness of Fe70Pd30 Nanostructured Thin Film

“…Nanoporous anodic alumina templates (NPAATs) with a square surface of 4 cm 2 , thickness of 500 μm, inter-hole distance P = 107 ± 3 nm, and hole diameter D = 80 ± 5 nm were fabricated via two-step mild anodization of high purity (99.999%) Al foils, which were electropolished with a mixture of H 3 PO 4 and H 2 SO 4 to improve the surface smoothness [ 23 ]. After cleaning and electropolishing at 50 V in perchloric acid and ethanol solution (1:3 vol., 9 °C) for 8 min, the Al foils were subjected to a two-step electrochemical anodization, as described elsewhere [ 23 , 24 ]. During the second anodization step, which lasted 6 h, the nanopores grew following the prepatterned engineering of a highly self-ordered hexagonal symmetry produced in the first anodization process.…”