Total Reflection X-ray Diffraction Research Articles

Enhancement the electrical conductivity of the synthesized polyvinylidene fluoride/polyvinyl chloride composite doped with palladium nanoparticles via laser ablation

The current work attempts to introduce polymer nanocomposite film based on the blended Poly(vinylidene fluoride) (PVDF) and Poly(vinyl Chloride) (PVC) and doped with different concentrations of palladium nanoparticles (PdNPs) were prepared by laser ablation technique. These nanoparticles; PdNPs doped PVDF/PVC was prepared to enhance the electrical conductivity of the synthesized film (PVDF/PVC) for suitable electrical applications. The structural and optical characterization have been investigated by means of ultraviolet–visible spectroscopy (UV–vis), Fourier transform infrared–attenuated total reflection analysis (FTIR-ATR) and X-ray diffraction (XRD). The electrical conductivity parameters as a function of frequency of PVDF/PVC/PdNPs were studied at room temperature. The addition of PdNPs improved the electrical conductivity of PVDF/PVC. Based on that, ist can be concluded that the obtained composites are conductive and suitable for batteries application.

Poultry litter ash characterisation and recovery

This paper reports a complete characterisation of poultry litter ash and its potential use as a heavy metal stabiliser. We propose a novel approach, in which the ashes deriving from municipal solid waste incineration (MSWI) are combined with poultry litter ash, rather than with coal combustion flue gas desulfurisation (FGD) residues. Heavy metals stabilisation was demonstrated by comparing the elemental concentrations in the leaching solutions of the starting raw and stabilised materials: leachable Pb and Zn showed a reduced solubility. The characterisation was conducted by total reflection X-ray fluorescence (TXRF), X-ray diffraction (XRD), micro-Raman spectroscopy and scanning electron microscopy combined with energy-dispersive X-ray spectrometry (SEM-EDX). The results showed that the poultry litter ash was Ca-, P-, K- and S-rich (>29 g/kg). It contained amorphous materials (i.e. fly ash economiser (FAECO) 73% and fly ash cyclone (FACYC) 61%) and soluble phases (e.g. arkanite and sylvite; up to 13% FAECO and 28% FACYC), as well as resilient crystalline (up to 2% of FAECO and FACYC) and amorphous phases (e.g. hydroxyapatite). After two months, the Pb and Zn concentrations in the leachate solutions were below the limit set by the European regulations for waste disposal (<0.2 mg/L and 1.5 mg/L, respectively). We propose a mechanism for the heavy metals stabilisation based on the carbonation process and high amounts of P, Ca and reactive amorphous phases. In conclusion, it is demonstrated that poultry litter ash can be an effective secondary source of heavy metals, allowing their immobilisation through P- and Ca-based reactive amorphous phases.

Structural Nanocomposite Fabrication from Self-Assembled Choline Chloride Modified Kaolinite into Poly(Methylmethacrylate)

Composite materials produced from indigenous nanoscale particles and synthetic polymers have created demand in the field of nanoscience and technology. Layered silicates are potential candidates for reinforcing the properties of composites. Here, we report the fabrication of nanocomposites using poly(methylmethacrylate) (PMMA) as the matrix and the Bijoypur clay of Bangladesh known as kaolinite (200–250 nm) as the filler via solution casting. Kaolinite was first modified using choline chloride to prepare core-shell particles through a precipitation technique and was used for self-assembled nanocomposite films preparation. A series of nanocomposites films using 0, 1, 3, 5 and 10% (w/w) modified kaolinite was prepared. The neat PMMA and nanocomposite films were characterized by attenuated total reflection infra-red (ATR-IR) spectroscopy and X-ray diffraction (XRD) techniques. The mechanical properties, thermal stability, and morphology of the films were investigated using a universal testing machine (UTM), a thermal gravimetric analyzer (TGA), and a scanning electron microscope (SEM). The nanocomposite films exhibited better mechanical properties and thermal stability than neat PMMA film. Development of such structural nanocomposite materials using naturally occurring nanoscale particles would play a crucial role in the field of materials science for packaging applications and separation technology.

Modified fly ash and zeolites as an effective adsorbent for metal ions from aqueous solution

Zeolite Na–X and chitosan-modified Na–X–CS were used as adsorbents for the removal of Cu(II), Fe(III), Mn(II) and Zn(II) from aqueous solutions. They were prepared based on fly ash by hydrothermal reaction using the NaOH solution under controlled conditions. Characterization of the Na–X and Na–X–CS sorbents was made using Fourier transform infrared spectroscopy with the attenuated total reflection mode, X-ray fluorescence and X-ray diffraction, nitrogen adsorption and desorption, acidity measurements and scanning electron microscopy techniques. The effects of adsorption time, the amount of sorbent and the concentration of metal ions on the removal percentage and sorption capacities were studied. The sorption percentage increased with the increasing phase contact time and zeolite amount. The adsorption mechanism was also discussed. The results revealed that Na–X–CS adsorbs Cu(II), Fe(III), Mn(II) and Zn(II) ions more effectively than zeolite Na–X and proved that modification by CS leads to an increase in the adsorption efficiency of the zeolites.

FTIR과 XRD를 이용한 출토 동물뼈의 화학적 평가 적용

동물뼈의 속성작용 정도에 따른 화학적 평가 기준을 적용하기 위하여 고고유적지에서 출토된 3종의 동물뼈와 현대 동물뼈 1종을 대상으로 FTIR-ATR과 XRD 분석을 실시하였다. FTIR-ATR 분석을 통해 결정화지수(CI)와 탄산염과 인산염의 비(C/P), 탄산염과 탄산염의 비(C/C)를 비교한 결과 동물뼈의 보존 상태에 따라 CI와 C/P 값이 차이를 보였다. XRD 분석을 통해 결정화 정도를 비교한 결과 <TEX>$30^{\circ}-35^{\circ}$</TEX> 범위에서 동물뼈의 보존 상태를 구분할 수 있었다. FTIR-ATR과 XRD 분석 결과, 몽골 대형포유류뼈의 보존 상태가 가장 양호하였고 나주 소뼈, 함안 소뼈의 순서로 보존 상태가 좋지 않았다. 이는 뼈 단면의 조직학 분석 결과와도 일치한다. 이를 통해 화학적 평가 기준은 우리나라에서 출토되는 동물뼈의 보존 상태를 파악하는데 적용이 가능할 것으로 판단된다. For the application of chemical assessment standards by the extent of diagenetic alteration, we investigated three archaeological animal bones and a modern animal bone using Fourier transform infrared-attenuated total reflection (FTIR-ATR) spectroscopy and x-ray diffraction (XRD) analysis. The calculating results of crystallinity index (CI), carbonate-to-phosphate (C/P) and carbonate-to-carbonate (C/C) using FTIR-ATR spectra showed differences CI and C/P according to the preservative condition of animal bones. By comparison of the crystallinity contents using XRD patterns, the states of animal bones were distinguished to the range of <TEX>$30^{\circ}-35^{\circ}$</TEX>. As results of FTIR-ATR and XRD analysis, it is suggested that Mongolian large mammals bone presents the best preservative condition, and cattle bone from Naju site, and Haman site followed. In addition, those were correlated with the results of histological index. The results suggested that the chemical assessment standards may contribute to application of predictions of the states of animal bones discovered from Korea.

Synthesis of Ti 1− xSn xO 2 nanosized photocatalysts in reverse microemulsions

The preparation of Ti 1− x Sn x O 2 nanocrystalline photocatalysts in reverse microemulsions is reported in this work. The obtained materials have been characterised by total reflection X-ray fluorescence (TXRF), X-ray diffraction (XRD) and Raman and UV–vis spectroscopies. Very good accordance between calculated and obtained compositions is observed. Undoped TiO 2 prepared in this way crystallises in the anatase phase. Tin-doped anatase is formed with x < 0.05, while both anatase and rutile phases crystallise when x ≥ 0.05. When both phases coexist, a preferential doping of rutile seems to occur. When x = 0.10, a multiphase mixture containing TiO 2(anatase), TiO 2(rutile) and SnO 2 was formed. No significant modification of the band gap is found in any case. The photocatalytic activity of the obtained catalysts is compared employing the trichloroethylene photocatalytic degradation as a test reaction. The beneficial effect of Sn 4+ in the activity of TiO 2 appears to be related to the formation of anatase–rutile mixtures, leading to the highest specific photocatalytic activity in the sample of composition Ti 0.93Sn 0.07O 2, with anatase:rutile ratio close to 3.

Observations of TiO2 Surfaces Using Totally Reflected X-ray In-plane Diffraction Under UV Irradiation

ABSTRACTSurface lattice displacements of titanium dioxide (TiO2: rutile) during ultra-violet (UV) light irradiation have been investigated using a total reflection x-ray diffraction, which provides a high signal to noise ratio (S/N) and superior in-plane surface diffraction. Under the environments in vapors of H2O, CH3OH, C2H5OH and C3H6OH, the photo-catalytic activities of TiO2 (110), (100) and (001) surfaces subject to UV irradiation have been measured. It is found that the diffraction peaks and their full width half maxima (FWHMs) show some peculiarities with respect to the photo-catalytic activities in both surface lattices and adsorbed molecules in vapors. Furthermore, Kelvin force microscopy (KFM) has showed that there exists a very high surface potential, probably due to surface atom displacements induced by UV irradiation. With regard to the origin of the photo-catalytic activities, the induced surface potentials are discussed.

Total-reflection X-ray diffraction study of friction-transferred poly(tetrafluoroethylene) film

The orientational structure of the friction-transferred poly(tetrafluoroethylene) (PTFE) film, which consists of highly oriented polymer strands, was evaluated with energy-dispersive total-reflection X-ray diffractometry. In the film, each PTFE molecule is oriented along the friction direction, and PTFE crystallites have a preferred orientation with respect to the substrate surface. The orientational distribution of the chain direction was quantitatively evaluated. The half-width of the distribution was determined to be about 3°. The dependence of the orientational distribution on temperature is discussed. © 2001 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 39: 432–438, 2001

Highly Oriented Nb-Doped Lead Titanate Thin Films by Reactive Sputtering: Fabrication and Structure Analyses

Highly oriented lead titanate thin films have been deposited on bare (100)MgO substrates and on (100)Pt/(100)MgO substrates by reactive sputtering. By adding metallic niobium chips to the target, Nb-doped PbTiO3 films could be obtained as well. The variation in the orientation of PbTiO3 films due to the deposition conditions is described in detail. Due to the highly oriented nature of the films, two types of X-ray diffraction methods were used to evaluate the effect of Nb doping on the tetragonality ratio c/a: one was the conventional θ–2θ Bragg-Brentano X-ray diffraction method (XRD), the other was the in-plane energy-dispersive total reflection X-ray diffraction method (ED-TXRD), which could provide the lattice vectors perpendicular (c axis) and parallel (a axis) to the substrate, respectively. Furthermore, the epitaxy of the deposited PbTiO3 films in relation to the (100)-cut MgO single crystal substrate could be confirmed using ED-TXRD.

In situ X-ray characterization of oligophenylene thin films prepared by organic molecular beam deposition

In order to examine organic thin films during the deposition, we newly developed in situ observation system of an energy dispersive total reflection X-ray diffraction (TRXD) equipped with an organic molecular beam deposition (OMBD). p-Sexiphenyl (6P), which is one of oligophenylenes, is noted as a useful material with unique optical properties by controlling the molecular orientation. To establish the method to control the molecular orientation in 6P thin films prepared by OMBD, 6P thin films on different substrates of silicon oxide (SiO 2) and uniaxially oriented poly( p-phenylene) (PPP) were examined by using in situ TRXD. In the case of the 6P thin films prepared on SiO 2, 6P molecules formed with the normal orientation from the initial process of the deposition. On the other hand, it was observed 6P molecules on the oriented PPP substrates formed with the parallel orientation along the PPP chains. By using out of plane measurements, it was revealed that the (203̄) planes of 6P crystallites preferentially oriented parallel to the substrate surface.

Mix-Crystallization of Two Dioxime Platinum Complexes by Coevaporation for Synthesizing One-Dimensional Superstructure

Mixed crystals of the one-dimensional metal complexes, bis(dimethylglyoximato)platinum(II) and bis(diethylglyoximato)platinum(II), were synthesized by a coevaporation technique. The continuous energy shift of the d−p transition was observed in the UV−vis absorption spectra of the coevaporated films. This energy shift shows that despite the difference in the crystal lattices between the two precursor complexes, both the metal complexes had mixed into the same column forming one-dimensional superstructures. Conventional X-ray diffraction and total reflection X-ray diffraction measurements showed that the anisotropic variation of the lattice constants depends on the mixing ratio. While the lattice constant parallel to the columns was approximately proportional to the mixing ratio, the variation of the constants perpendicular to the columns deviated substantially from a linear relation. This indicates that the one-dimensional framework of the mixed columns was maintained even though there is significant lattice mismatch between the precursor metal complexes.

MOCVD of Pb-based ferroelectric oxide thin films

Pb-based ferroelectric oxide thin films such as PbTiO 3 and Pb(Zr,Ti)O 3 (PZT) were successfully prepared on Pt(1 1 1)/SiO 2/Si(1 0 0) and Pt(1 0 0) MgO(1 0 0) by MOCVD. The effects of the growth parameters on the film composition, crystalline structure and electrical properties were investigated. The large area growth and step coverage characteristics are also described. Energy-dispersive-type total reflection X-ray diffraction (ED-TXRD) and conventional θ-2θ X-ray diffraction analyses were performed to characterize PbTiO 3, PZT and Pt on MgO. PbTiO 3, PZT and Pt were epitaxially grown on MgO and the in-plane film orientation was strongly dependent on that of Pt on MgO. It was also found that the lattice parameters of PbTiO 3 in the PbTiO 3/Pt/MgO structure were influenced by the film thickness. On the other hand, the lattice parameters of Pt were only slightly influenced by the film thickness of PbTiO 3.

Characterization of Pb(Zr,Ti)O3 thin films by MOCVD using the total reflection X-ray diffraction method

PZT thin film of 250nm thickness was prepared on Pt/MgO(100) by metal-organic chemical vapor deposition(MOCVD). The vertical structure of PZT was evaluated using θ-2θ XRD method. The “in-plane” structure and orientation relationship between PZT, Pt and MgO was evaluated using energy-dispersive typed total reflection X-ray diffraction method.

In-situ Observation of Fullerene Ultrathin Films by Using Total Reflection X-ray Diffraction-Organic Molecular Beam Deposition Method(TRXD-OMBD).

For the purpose of confirming the growth mechanism of organic ultrathin films prepared by organic molecular beam deposition (OMBD), we employed a new combined system of total reflection X-ray diffraction method (TRXD) and OMBD. By using this system (TRXD-OMBD), the in-situ observation of cohesive structures and growth modes in organic ultrathin films were performed. In this study, the in-plane structure and orientation of fullerene (C60) ultrathin films epitaxially grown on oriented silver (Ag) surfaces were examined during the deposition. It was confirmed that the C60 ultrathin film formed the hexagonal closed packed (hcp) structure and the epitaxial structure of C60 on the Ag (111) surface occurred at the thickness of a few nanometer, namely the (2√3× 2√3) R30° structure as a stable state. Further, the growth modes of C60 ultrathin films were examined by the in-situ observation of total reflection fluorescence X-rays of Ag. In this paper, we noted the possibility of various analysis on organic ultrathin films and surfaces by our TRXD-ONBD system.

Dependence of Crystalline Structure and Lattice Parameters on Film Thickness in PbTiO3/Pt/MgO Epitaxial Structure

In PbTiO3 (2.2–398 nm in thickness)/Pt/MgO(100) structure, the dependence of the crystalline structure and lattice parameters of PbTiO3 thin films on the film thickness was investigated using the θ-2θ XRD method and the energy dispersive typed total reflection X-ray diffraction method (ED-TXRD). By using the ED-TXRD method, we can easily evaluate the in-plane structure of island-structured PbTiO3 films at the initial growth stage. Although the PbTiO3 thin films were highly c-axis orientated, the formation of some a-domains was observed with increasing thickness. The lattice parameters of the vertical dimension were dependent on the film thickness, unlike those in-plane. From these experimental results, the inner strain occurring in PbTiO3 thin films is discussed.

Direct observation of the crystallization in EL organic thin films by total reflection X-ray diffractometer

The degradation of amorphous organic electroluminescent (EL) devices is generally assumed due to the crystallization enhanced by the Joule heat. Here, in order to reveal directly the structural changes in organic EL films during an annealing process, we performed first total reflection X-ray diffraction measurements for N,N′-diphenyl- N,N′-bis(3-methylphenyl)-[1,1′-biphenyl]-4,4′-diamine (TPD) films vapor-deposited on SiO 2 glass substrates. Atomic force microscopy (AFM) was also used to observe the morphological modifications through annealing. The X-ray data revealed that the TPD film remained amorphous below 100°C, followed by a gradual change into crystalline during annealing. Moreover, combining this result with the AFM data, we found that there existed some relationship between morphological change and crystallization in the film.

In situ observation of the in-plane structure of C60 thin films on metal substrates prepared by molecular beam deposition

Recently, it has been reported that fullerene (C60) thin films deposited on Ag ( 111 ) surfaces by molecular beam deposition (MBD) have a high degree of crystallinity and are oriented to the substrate surface. However, because there exists only a few characterization methods to directly examine the in-plane structure of the ultrathin film, such as STM, the details were not understood sufficiently. We employed a new system of an energy-dispersive type total-reflection X-ray diffraction (TRXD) method combined with organic molecular beam deposition (OMBD). The TRXD method is developed for the high-sensitivity measurement of the in-plane structure in organic thin films. By using this in situ and real-time observation, the growth process of C60 ultrathin films on Ag (111) surface was observed at the range of a few nanometers. As a result, we confirmed the in-plane structure and the epitaxy on the substrate surface.

Evaluation of Thin Films of Functional Organic Materials by Total Reflection X-Ray Diffraction

Abstract The crystal structure and molecular orientation of lead phthalocyanine (PbPc) thin films onto a silicon (Si) and potassium bromide (KBr) were in-situ observed by using the new system combined a total reflection X-ray diffraction (TRXD) with an organic molecular beam deposition (OMBD). When the substrate was kept at a temperature of 25°C, the deposited films consisted of monoclinic crystals and the PbPc molecules tend to orient with the column axis parallel to the surface. Further, the films deposited on Si at 100°C consisted of the triclinic crystals with the column axis parallel to the surface. While, the thin films on KBr exhibited much higher crystallinity than on Si, and same structures even if the substrate temperature of 180°C was raised after deposition.

Simultaneous Analysis of Total Reflection X-Ray Diffraction and Fluorescence from Copper-Phthalocyanine Thin Films during Evaporation Process

A newly developed X-ray measuring system, capable of simultaneously conducting total-reflection X-ray diffraction (TXRD) and total-reflection X-ray fluorescence (TXRF) analyses, was utilized to follow the adsorption and structural changes in copper phthalocyanine (CuPc) thin films during an evaporation process. The intensities of Cu Kα fluorescent X-rays provided precise data on the amount of CuPc molecules adsorbed on the substrate of SiO2, and thus the difference in adsorption coefficient of CuPc molecules on the SiO2 substrate and the oscillator surfaces of Ag could be evaluated in the first place. Moreover, by combining these fluorescent data with the diffraction data we could follow the exact changes of molecular orientation with the increase of film thickness. The data on the film thickness variations of the X-ray profiles revealed that the structural change in the CuPc molecular crystal occurred at about 9 nm thickness of the evaporated film.

Structural Evaluation and Molecular Control of Vacuum-Evaporated Organic Thin Films

Recently, organic molecules and their complexes with inorganic or metallic materials have drawn many researchers' interest as candidate materials for nanoscale electronic devices of the next generation, especially since Carter's proposal on molecular electronic devices (MEDs) with the functions of gating, switching, memory, etc. in one molecule. However, in order to build such nanoscopic organic electronic devices to replace conventional silicon-based inorganic devices, one must determine how to produce such nanoscale devices and to recognize the electronic states of a single molecule.The scanning tunneling microscope (STM) developed by G. Binning and H. Rohrer made it possible to visualize atoms and molecules in real space under various atmospheres. In addition, STMs can be used as nanoscopic tools for manipulation of individual atoms and molecules, thus realizing MEDs and nanotechnology.In this article, we present our recent achievements concerning the STM as well as in situ x-ray diffraction studies on the molecular structure of ultrathin films prepared by vacuum evaporation. STM observations with atomic resolution reveal the mechanism of nuclei formation and the crystal-growth process in organic molecules. Computer simulations based on STM images of polar organic molecules with electronic dipoles have elucidated the role of electronic interaction for their aggregation structures.Also, nanometer-sized molecular memory can be created by applying an electronic pulse to the evaporated organic films through the STM tip. Furthermore, we discuss the principle of a newly developed in situ total reflection x-ray diffraction (TRXD) apparatus and its application to the evaluation of crystal structure and molecular orientation in organic thin films during the evaporation process, particularly in regard to the role of the substrate, that is, epitaxial growth on organic molecular crystals.