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Modeling and optimization of characterization of nanostructure anodized aluminium oxide membranes
摘要： This study indicates the importance of statistical analysis and modeling to investigate the synthesis and optimization of anodized aluminium oxide (AAO) properties for template-assisted synthesis of nanostructure particles. The response surface methodology was used to optimize pore size and porosity of AAO. The impacts of four main parameters including type of acidic electrolyte, concentration of acid, bath temperature and electrical potential of anodization on characterization of AAO were investigated. Statistical analysis showed that the linear and quadratic terms of these variables had significant effects. Based on the statistical analysis, a possible mechanism of the anodization was proposed. The proposed mechanism helped us to develop an analytical model. The analytical model could predict the experimental results with an appropriate accuracy. Results indicated the rate-limiting reaction in anodization process is water dissociation which was conducted at the pore bottom of the AAO. In addition, concentrated electrical field at pore base induced water splitting so that the activation energy of water dissociation decreased ten times and reached to 9898.5 J/mol.
关键词： Statistical analysis,Anodized aluminium oxide,Electrochemical synthesis,Pore perforation,Nanoporous materials
更新于2025-09-23 15:23:52
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Nanoconfined water vapour as a probe to evaluate plasmonic heating
摘要： Engineering the photothermal effect in plasmonic materials is of paramount importance for many applications such as cancer therapy, chemical synthesis, cold catalysis and more recently for metasurfaces. Evaluation of plasmonic heating at the nanoscale is challenging and generally requires sophisticated equipments and/or temperature-sensitive probes such as fluorescent molecules or materials. Here we propose to use water vapor as probe to evaluate the local heating around plasmonic nanoparticles. We demonstrated the concept for the case of a plasmonic colloidal film composed by a bi-modal nanoporosity. In particular we exploit the thermal and light water liquid-vapor phase transitions taking place into the nanoporous medium that can be triggered by external stimulus such as heating or irradiation to obtain structural and optical variations in the films. Estimation of the local temperature was then obtained by using spectroscopic ellipsometry acquired by a multimodal chamber. More generally, this method offer a simple and general approach to determine local temperature that only requires a nanoporous material and water vapor, such as environmental humidity. In addition this approach can be further generalized to other materials, vapor molecules or optical technique.
关键词： local temperature measurement,spectroscopic ellipsometry,water vapor,nanoporous materials,plasmonic heating
更新于2025-09-23 15:19:57
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Simple and Rapid Fabrication Process of Porous Silicon Surface Using Inductively Coupled Plasma Reactive Ion Etching
摘要： In this study, the simple and rapid formation of porous silicon on a pillar array structure using inductively coupled plasma reactive ion etching (ICP-RIE) is realized. This method can render the outermost surface porous without using an additional etching or deposition apparatus because the same equipment is used to form the structure. As a basic experiment, we attempted to etch the structure by considerably varying three parameters (bias power, chamber pressure, and gas ?ow rate) in ICP-RIE. The etching step condition was determined for the porous structure from the result. Furthermore, we obtained a porous pillar surface while almost maintaining the structure by performing multicycle etching and an additional passivation step. A number of pores (diameter: ～100 nm) were formed randomly on the side wall of the pillar array using the proposed method. Compared with original pillar, the surface roughness of porous pillar increased by 48%. [2019-0216]
关键词： nanoporous materials,Etching,microstructure,silicon
更新于2025-09-16 10:30:52
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Molecularly imprinted photonic hydrogel sensor for optical detection of L-histidine
摘要： A molecularly imprinted photonic hydrogel (MIPH) is described for the optical determination of L-histidine (L-His). The inverse opal structure of MIPH was obtained by placing silica particles (230 nm) in molecularly imprinted polymer on a glass slide. After being fully etched by hydrofluoric acid, this inverse opal structure brings about a high specific surface and plentiful binding sites for L-His. If L-His is absorbed by the modified MIPH, its average effective refraction coefficient is increased. This causes the Bragg diffraction peak to be red-shifted by about 34 nm as the concentration of L-His increases from 0 to 100 nM. Much smaller diffraction peak shifts are obtained for other amino acids. The detection limit of this method is 10 pM. The response time towards L-His is as short as 60 s. In addition, the sensor can be recovered by treatment with 0.1 M acetic acid/methanol. It was applied to the determination of L-His in drinks sample.
关键词： Inverse opal structure,St?ber method,Nanoporous materials,Photonic crystal array,UV curing,Bragg diffraction peak,Hydrogen bonding,Reflection spectrum
更新于2025-09-10 09:29:36