Selective Depositions of Fe-Containing Oxide Films on Mixed Selfassembled Organic Monolayers using Microcontact Printing

1999 ◽  
Vol 576 ◽  
Author(s):  
Hyunjung Shin ◽  
Hyejin Im ◽  
Seungbum Hong ◽  
Kyongmi Lee ◽  
Geunbae Lim ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Aqueous Solutions ◽  
Microcontact Printing ◽  
Thin Layers ◽  
Organic Monolayers ◽  
Selective Deposition ◽  
X Ray ◽  
Si Substrates ◽  
Relief Structure ◽  
Oxide Phases

ABSTRACTIn situ patterning of crystalline iron oxide thin layers has been achieved via microcontact printing (μCP) and selective deposition. μCP was used to pattern two different surface moieties of selfassembled organic monolayers (SAMs) on Au/Cr/Si substrates. An elastomeric stamp (poly(dimethylsiloxane); PDMS) having a submicron-size patterned relief structure was used to transfer either hexadecanethiol (HDT) SAMs, which are to sustain deposition of iron oxide precipitates, or hydrophilic SAMs (e.g. dithiothreitol (DTT)). Selective deposition is realized through precipitation of iron oxide phases from aqueous solutions at ambient temperature (<100°C). Aqueous solutions of 0.05 M of iron nitrate (Fe(NO3)2•9H20) containing urea under nitric acid (pH < 2) were prepared for selective depositions. X-ray photoelectron spectroscopic (XPS) results showed that iron oxide precipitates were deposited onto hydrophilic SAMs, but not onto HDT surfaces. As-deposited films onto DTT-SAM surfaces at 80°C were crystalline α-Fe2O3 (hematite). Fe3O4 and γ-Fe2O3 films were synthesized via annealing of as-deposited α-Fe2O3. Scanning electron microscopy, x-ray diffractometry, vibrating sample magnetometry, and optical microscopy were used to characterize the films' microstructures and properties.

Formation and characterization of crystalline iron oxide films on self-assembled organic monolayers and their in situ patterning

2001 ◽  
Vol 16 (2) ◽  
pp. 564-569 ◽  
Author(s):  
Hyunjung Shin ◽  
Jong Up Jeon ◽  
Y. Eugene Pak ◽  
Hyejin Im ◽  
Eung Soo Kim
Keyword(s):  
Iron Oxide ◽  
Microcontact Printing ◽  
Oxide Films ◽  
Thin Layers ◽  
Organic Monolayers ◽  
Selective Deposition ◽  
Si Substrates ◽  
Self Assembled ◽  
Iron Oxide Films

Crystalline and pore-free films of α–Fe2O3 were prepared on hydrophilic self-assembled organic monolayers (DTT-SAMs) at 80 °C. Subsequently, Fe3O4 and γ–Fe2O3 films were synthesized via post annealing of as-deposited α–Fe2O3. In situ patterning of crystalline iron oxide thin layers was achieved via microcontact printing (μCP) and selective deposition. μCP was used to pattern two different surface moieties of self-assembled organic monolayers (SAMs) on Au–Cr–Si substrates. An elastomeric stamp was used to transfer either hexadecanethiol (HDT) SAMs, which are to sustain deposition of iron oxide precipitates, or hydrophilic SAMs [e.g., dithiothreitol (DTT)]. Selective deposition was realized through precipitation of iron oxide phases. Iron oxide films were deposited onto hydrophilic SAMs, but not onto HDT surfaces. Line (width of <1 μm) patterns in crystalline α–Fe2O3 thin films were obtained.

scholarly journals Removal and Oxidation of As(III) from Water Using Iron Oxide Coated CTAB as Adsorbent

Polymers ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 1687 ◽  
Author(s):  
Daniela Predoi ◽  
Simona Liliana Iconaru ◽  
Mihai Valentin Predoi ◽  
Mikael Motelica-Heino
Keyword(s):  
Iron Oxide ◽  
Aqueous Solutions ◽  
Photoelectron Spectroscopy ◽  
Arsenic Removal ◽  
Morphological Changes ◽  
Xrd Analysis ◽  
Precipitation Method ◽  
Cubic Phase ◽  
Separation Procedure ◽  
X Ray

Iron oxides such as magnetite and maghemite coated with cetyltrimethylammonium bromide (CTAB) are very promising materials for wastewater treatment because iron oxide can be easily separated from solutions using the magnetic separation procedure Iron oxide (IO) coated CTAB was synthesized by an adapted co-precipitation method. In the present study, the IO-CTAB was used for removing arsenic from water for the first time. In the present study, the performance of iron oxide coated CTAB biocomposites as an adsorbent for arsenic removal from aqueous solutions was examined. X-ray diffraction (XRD) analysis and the results revealed a cubic phase Fd-3 m of Fe3O4 with lattice a = 8.40 Å and average crystal size equal to 17.26 ± 3 nm. The mean particle size calculated from transmission electron microscopy (TEM) was 19.86 ±1.7 nm. The results of the adsorption batch experiments and the data determined using the Langmuir and Freundlich models emphasized that IO-CTAB nanoparticles were favorable for the adsorption of As(III) ions from aqueous solutions. Ultrasound measurements have shown that IO-CTAB is a cost-effective biocomposite for removing arsenic from contaminated solutions. Moreover, x-ray photoelectron spectroscopy (XPS) has shown that during the process of arsenic absorption, there is oxidation from As(III) to As(V), which leads to a decrease in toxicity during this process. The results of the cytotoxic assays confirmed that the IO-CTAB nanoparticles did not induce any morphological changes in the HeLa cells and did not affect their proliferation after 24 h of incubation.

Raman and Impedance Spectroscopy of Blend Polycarbonate and Zinc Oxide Layers Grown by Sol-Gel Method

2013 ◽  
Vol 200 ◽  
pp. 22-26 ◽  
Author(s):  
Pawel Popielarski ◽  
Kazimierz Paprocki ◽  
Waclaw Bala ◽  
Agnieszka Banaszak-Piechowska ◽  
Karolina Walczyk ◽  
...  
Keyword(s):  
Sol Gel ◽  
Thin Layers ◽  
X Ray Diffraction ◽  
Confocal Raman Spectroscopy ◽  
Gel Method ◽  
X Ray ◽  
Sol Gel Method ◽  
Si Substrates ◽  
Surface Spectroscopy ◽  
Different Content

Confocal Raman spectroscopy has been applied to investigate blend polycarbonate and ZnO thin layers with different thicknesses and different content of ZnO. The admittance spectroscopy have been applied to correlation of optical and electrical properties of these layers used in electroluminescence diodes and photovoltaic cells. The I-V (DC and AC) characteristics and thermally stimulated current (TSC) have been applied to the study of the deep levels in ZnO thin films grown by sol-gel method onto Si substrates. The surface spectroscopy morphology of the samples were investigated by scanning microscopy and X ray diffraction.

X-ray spectromicroscopy of nanoparticulate iron oxide phases

2016 ◽  
Vol 11 (4) ◽  
pp. 04B402 ◽  
Author(s):  
Paul M. Dietrich ◽  
Wolfgang E. S. Unger ◽  
Sufal Swaraj
Keyword(s):  
Iron Oxide ◽  
X Ray ◽  
Oxide Phases

Identification of iron oxide phases in thin films grown on Al2O3(0001) by Raman spectroscopy and X-ray diffraction

2010 ◽  
Vol 604 (7-8) ◽  
pp. 679-685 ◽  
Author(s):  
Maike Lübbe ◽  
Alexander M. Gigler ◽  
Robert W. Stark ◽  
Wolfgang Moritz
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Iron Oxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxide Phases

STRUCTURE AND PHOTOLUMINESCENT PROPERTIES OF SiCO THIN-FILMS DOPED WITH Al PREPARED BY DUAL MAGNETRON SPUTTERING

2011 ◽  
Vol 25 (16) ◽  
pp. 2149-2156
Author(s):  
JICHENG ZHOU ◽  
XUQIANG ZHENG ◽  
ZHIJIE SHI ◽  
BAOXING ZHAO ◽  
FU LIU ◽  
...  
Keyword(s):  
Thin Films ◽  
Energy Dispersive Spectrometer ◽  
Thin Layers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Force Microscopy ◽  
Si Substrates ◽  
Atomic Force ◽  
Related Defect ◽  
Amorphous Sic

SiCO thin-films doped with aluminum (Al) prepared by alternate deposition of SiC and Al thin layers using Ar and O 2 as sputtering gas were deposited on n- Si substrates. The as-deposited thin-films were annealed under 600°C in nitrogen ambient. The thin-films have been characterized by atomic force microscopy, energy dispersive spectrometer, X-ray diffraction, fourier transform infrared spectroscopy, and photoluminescence spectra. The results showed that the introduction of Al promotes the formation of Si — C bonds, but hinders amorphous SiC to further transform to crystalline SiC . The doped Al would react with SiO x in the thin-films to form more Si particles which strongly affect the optical properties. After Al doped, there presented a seven times of enhancement emission band centered around 412 nm, which is ascribed to nanostructure Si -related defect centers embedded in the SiCO thin-films. The obtained results are expected to have important applications in modern optoelectronic devices.

The thermal disintegration of crocidolite in air and in vacuum

1965 ◽  
Vol 35 (269) ◽  
pp. 31-37 ◽  
Author(s):  
J. H. Patterson
Keyword(s):  
Iron Oxide ◽  
Structural Models ◽  
Fibre Axis ◽  
Orientation Relationships ◽  
Incongruent Melting ◽  
Fibre Bundles ◽  
X Ray ◽  
Oxide Phases ◽  
Original Fibre

SummaryThe thermal disintegration of crocidolite has been investigated with X-ray powder and rotation photographs. Initial disintegration products include monoclinic pyroxene, iron oxide phases, and eristobalite as a pseudomorph of the original fibre bundles but at about 1000° C fusion occurs due to incongruent melting of the pyroxene. The products are strongly oriented along the fibre axis and full orientation relationships have been deduced with the aid of structural models. From these relationships it is suggested that regions of the amphibole structure on (100) are retained in the product phases without change in orientation.

Reaction Pathways at the Iron–microspherical Silica Interface: Mechanistic Aspects of the Formation of Target Iron Oxide Phases

2000 ◽  
Vol 15 (4) ◽  
pp. 944-950 ◽  
Author(s):  
Sivarajan Ramesh ◽  
Israel Felner ◽  
Yuri Koltypin ◽  
Aharon Gedanken
Keyword(s):  
Iron Oxide ◽  
Iron Nanoparticles ◽  
Silica Surface ◽  
Adsorbed Water ◽  
Reaction Pathways ◽  
X Ray ◽  
Degree Of Hydration ◽  
Oxide Phases ◽  
And Control ◽  
Hydrolysis Of

Oxidative hydrolysis of elemental iron nanoclusters on hydroxylated surfaces such as silica or alumina is known to be influenced by the degree of hydration of the surface. The understanding and control of this process is crucial in the synthesis of iron oxide coated silica microspheres with a desired magnetic property. The hydrolysis of iron nanoparticles followed by heat treatment in the case of a hydrated microspherical silica surface results in the formation of maghemite (γ–Fe2O3), whereas a dehydrated surface yielded hematite (α–Fe2O3) nanoparticles. The influence of adsorbed water on the formation of intermediate iron oxides/oxidehydroxides and the mechanistic aspects of their subsequent thermal dehydration iron oxide phases were investigated by thermogravimetric analysis, Fourier transform infrared, and Mössbauer spectroscopies. The reactions on both the hydrated and the dehydrated surfaces were found to proceed through the formation of an x-ray amorphous lepidocrocite [γ–FeO(OH)] intermediate and its subsequent dehydration to maghemite (γ–Fe2O3). Maghemite to hematite transformation was readily facilitated only on a dry silica surface. The retardation of the lepidocrocite →maghemite →hematite transformation in the case of a hydrated silica surface is suggested to arise from strong hydrogen-bonded interactions between the substrate silica and the adsorbed nanoparticles.

A case of rhinolithiasis in Botswana: a mineralogical, microscopic and chemical study

2002 ◽  
Vol 116 (12) ◽  
pp. 1036-1040 ◽  
Author(s):  
Bernard W. Vink ◽  
Piet van Hasselt ◽  
Richard Wormald
Keyword(s):  
Iron Oxide ◽  
Chemical Study ◽  
Thin Layers ◽  
Calcium Stearate ◽  
X Ray Diffraction ◽  
Growth Rings ◽  
Amorphous Iron ◽  
X Ray ◽  
Electron Microscope Analysis ◽  
Elliptical Core

A case of rhinolithiasis in Southeast Botswana was treated and after removal in hospital, the rhinolith was subjected to macroscopic and microscopic examination, X-ray diffraction analysis, electron microscope analysis and partial botanical analysis.The rhinolith consists of a strongly elliptical core of calcium stearate (C36H70CaO4.H2O), surrounded by approximately 30 elongated concentric growth rings, consisting of sodium-containing whitlockite (Ca18Mg2(Na,H)(PO4)14). The different layers have various degrees of porosity and red staining, probably due to traces of amorphous iron oxide. The origin of the rhinolith started with a piece of plant material, lodged in the nose, which was replaced by calcium stearate, leaving some remnants of resistant epidermal plant tissue. During subsequent years, thin layers of whitlockite were deposited periodically around the core with the reddish brown bands representingdeposition during the dry season when atmospheric dust rich in amorphous iron oxide is at its highest in Botswana.

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