Mechanisms of Nanoporous Alumina Formation and Self-organized Growth

Molecular self-assembly of nylon-12 nanorods cylindrically confined to nanoporous alumina

IUCrJ ◽

10.1107/s2052252514020132 ◽

2014 ◽

Vol 1 (6) ◽

pp. 439-445 ◽

Cited By ~ 7

Author(s):

Yan Cao ◽

Hui Wu ◽

Yuji Higaki ◽

Hiroshi Jinnai ◽

Atsushi Takahara

Keyword(s):

Hydrogen Bonding ◽

Self Assembly ◽

Growth Direction ◽

Two Dimensional ◽

Nanoporous Alumina ◽

Self Organized ◽

Selected Area Electron Diffraction ◽

Transmission Electron ◽

Nylon 12 ◽

Different Diameters

Molecular self-assembly of nylon-12 rods in self-organized nanoporous alumina cylinders with two different diameters (65 and 300 nm) is studied with transmission electron microscopy (TEM) and wide-angle X-ray diffraction (WAXD) in symmetrical reflection mode. In a rod with a 300 nm diameter, the tendency of the hydrogen-bonding direction of a γ-form crystal parallel to the long axis of the rod is not clear because of weak two-dimensional confinement. In a rod with a diameter of 65 nm, the tendency of the hydrogen-bonding direction of a γ-form crystal parallel to the long axis of the rod is more distinct because of strong two-dimensional confinement. For the first time, selected-area electron diffraction (SAED) is applied in a transmission electron microscope to a polymer nanorod in order to determine the hydrogen-bond sheet and lamellar orientations. Results of TEM–SAED and WAXD showed that the crystals within the rod possess the γ-form of nylon-12 and that thebaxis (stem axis) of the γ-form crystals is perpendicular to the long axis of the rod. These results revealed that only lamellae with 〈h0l〉 directions are able to grow inside the nanopores and the growth of lamellae with 〈hkl〉 (k≠ 0) directions is stopped owing to impingements against the cylinder walls. The dominant crystal growth direction of the 65 nm rod in stronger two-dimensional confinement is in between the [−201] and [001] directions due to the development of a hydrogen-bonded sheet restricted along the long axis of the rod.

Download Full-text

FABRICATION OF SELF-ORGANIZED METAL NANOWIRE ARRAY USING POROUS ALUMINA TEMPLATE FOR OFF-CHIP INTERCONNECTS

International Journal of Nanoscience ◽

10.1142/s0219581x06004620 ◽

2006 ◽

Vol 05 (04n05) ◽

pp. 453-458 ◽

Cited By ~ 3

Author(s):

S. BALAKRISHNAN ◽

V. KRIPESH ◽

SER CHOONG CHONG

Keyword(s):

Silicon Wafer ◽

Porous Alumina ◽

Nanowire Array ◽

Oxalic Acid Solution ◽

Aluminum Film ◽

Native Oxide ◽

Alumina Template ◽

Nanoporous Alumina ◽

Self Organized ◽

Nickel Nanowire

Porous anodic alumina formation on silicon substrate is an example of a nanostructured porous array that is well-suited as a template for growing metallic nanowires. Commercial silicon wafer deposited with aluminum is used as substrate. Prior to anodization, the aluminum film is cleaned with mixture of acids solution to remove its native oxide growth. Anodization of aluminum film on silicon wafer is performed in oxalic acid solution to generate uniform and self-organized nanoporous alumina film. The pores are in the range of 60 nm diameter and pore density is about 9 × 109/ cm 2. The nanoporous alumina template is filled with nickel nanowires by wet electrodeposition process. After nanowire is grown on silicon wafer, the alumina template is etched and the as grown nickel nanowire forest is patterned using laser pruning method. The crystallinity pattern of the as grown nickel naowire forest is characterized using X-ray diffraction technique.

Download Full-text

Nanoporous alumina formed by self-organized two-step anodization of Ni3Al intermetallic alloy in citric acid

Applied Surface Science ◽

10.1016/j.apsusc.2012.10.074 ◽

2013 ◽

Vol 264 ◽

pp. 605-610 ◽

Cited By ~ 16

Author(s):

Wojciech J. Stępniowski ◽

Grzegorz Cieślak ◽

Małgorzata Norek ◽

Krzysztof Karczewski ◽

Marta Michalska-Domańska ◽

...

Keyword(s):

Citric Acid ◽

Intermetallic Alloy ◽

Nanoporous Alumina ◽

Self Organized ◽

Ni3al Intermetallic

Download Full-text

Problem behavior in autism spectrum disorders: A paradigmatic self-organized perspective of network structures

Behavioral and Brain Sciences ◽

10.1017/s0140525x18001188 ◽

2019 ◽

Vol 42 ◽

Author(s):

Lucio Tonello ◽

Luca Giacobbi ◽

Alberto Pettenon ◽

Alessandro Scuotto ◽

Massimo Cocchi ◽

...

Keyword(s):

Autism Spectrum Disorder ◽

Problem Behaviors ◽

Autism Spectrum ◽

The Self ◽

Network Structures ◽

Self Organized ◽

Critical Equilibrium ◽

Self Organized Criticality ◽

Acute Agitation ◽

Spectrum Disorders

AbstractAutism spectrum disorder (ASD) subjects can present temporary behaviors of acute agitation and aggressiveness, named problem behaviors. They have been shown to be consistent with the self-organized criticality (SOC), a model wherein occasionally occurring “catastrophic events” are necessary in order to maintain a self-organized “critical equilibrium.” The SOC can represent the psychopathology network structures and additionally suggests that they can be considered as self-organized systems.

Download Full-text

Compact and efficient gas diffusion electrodes based on nanoporous alumina membranes for microfuel cells and gas sensors

The Analyst ◽

10.1039/c9an01882d ◽

2020 ◽

Vol 145 (1) ◽

pp. 122-131 ◽

Cited By ~ 1

Author(s):

Wanda V. Fernandez ◽

Rocío T. Tosello ◽

José L. Fernández

Keyword(s):

Response Times ◽

Hydrogen Oxidation ◽

Fast Response ◽

Gas Diffusion ◽

Limiting Current ◽

Gas Diffusion Electrodes ◽

Nanoporous Alumina ◽

Alumina Membranes ◽

Current Densities ◽

Microfuel Cells

Gas diffusion electrodes based on nanoporous alumina membranes electrocatalyze hydrogen oxidation at high diffusion-limiting current densities with fast response times.

Download Full-text