Wide-angle Powder X-ray Diffraction Research Articles

Mesoporous CdS via Network of Self-Assembled Nanocrystals: Synthesis, Characterization and Enhanced Photoconducting Property.

Semiconduction nanoparticles are intensively studied due to their huge potential in optoelctronic applications. Here we report an efficient chemical route for hydrothermal synthesis of aggregated mesoporous cadmium sulfide (CdS) nanoparticles using supramolecular-assembly of ionic and water soluble sodium salicylate as the capping agent. The nanostructure, mesophase, optical property and photoconductivity of these mesoporous CdS materials have been characterized by using small and wide angle powder X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), N2-sorption, Raman analysis, Fourier transformed infrared (FT-IR), UV-Visible DSR spectroscopy, and photoconductivity measurement. Wide angle XRD pattern and high resolution TEM image analysis suggested that the particle size of the materials is within 10 nm and the nanoparticles are in well-crystallized cubic phase. Mesoporous CdS nanoparticles showed drastically enhanced photoelectrochemical response under visible light irradiation on entrapping a photosensitizer (dye) molecule in the interparticle spaces. Efficient synthesis strategy and the enhanced photo response in the mesoporous CdS material could facilitate the designing of other porous semiconductor oxide/sulfide and their applications in photon-to-electron conversion processes.

Small-granule starches from sweet corn and cow cockle: Physical properties and amylopectin branching pattern

Small-granule starches (SGS) attract growing interests with their unique structure and functionalities, such as fat replacement and texture modifications. To explore new resources of SGS, sweet corn starch (SCS) and cow cockle starch (CCS) were studied for their physical properties and branching pattern, with normal corn starch, waxy corn starch, normal rice starch, and waxy rice starch as comparisons. Hydrothermal and wide-angle X-ray powder diffraction analyses showed the much lower content of ordered structure (melting enthalpy of 5.6 J/g) and lower crystallinity (28%) for SCS than for normal corn starch (14.4 J/g and 34%, respectively). The rapid viscosity analyzer analysis showed very low viscosity for SCS through the pasting process and high resistance of CCS against the shear force. The results of β-limit dextrin structure analyses showed highly branched clusters of SCS (about 15 glucan chains per cluster) and a lack of long inter-cluster chains that connect 3 or more clusters. In contrast, CCS displayed a branching pattern similar to that of corn starches, however, with fewer short intra-cluster chains. It was considered that the low crystallinity and viscosity of SCS were attributed to its high branching, which reduced the formation of crystalline structure during the genesis of starch and decreased the interactions among swollen granules. On the other hand, the submicron size made CCS granules less susceptible to the shear force applied during pasting, leading to negligible breakdown. Using SCS and CCS as models, this study connected the physical properties and branching pattern of SGS, thus supporting their potential applications.

Transcription of Nanofibrous Cerium Phosphate Using a pH-Sensitive Lipodipeptide Hydrogel Template

A novel and simple transcription strategy has been designed for the template-synthesis of CePO4·xH2O nanofibers having an improved nanofibrous morphology using a pH-sensitive nanofibrous hydrogel (glycine-alanine lipodipeptide) as structure-directing scaffold. The phosphorylated hydrogel was employed as a template to direct the mineralization of high aspect ratio nanofibrous cerium phosphate, which in-situ formed by diffusion of aqueous CeCl3 and subsequent drying (60 °C) and annealing treatments (250, 600 and 900 °C). Dried xerogels and annealed CePO4 powders were characterized by conventional thermal and thermogravimetric analysis (DTA/TG), and Wide-Angle X-ray powder diffraction (WAXD) and X-ray powder diffraction (XRD) techniques. A molecular packing model for the formation of the fibrous xerogel template was proposed, in accordance with results from Fourier-Transformed Infrarred (FTIR) and WAXD measurements. The morphology, crystalline structure and composition of CePO4 nanofibers were characterized by electron microscopy techniques (Field-Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy/High-Resolution Transmission Electron Microscopy (TEM/HRTEM), and Scanning Transmission Electron Microscopy working in High Angle Annular Dark-Field (STEM-HAADF)) with associated X-ray energy-dispersive detector (EDS) and Scanning Transmission Electron Microscopy-Electron Energy Loss (STEM-EELS) spectroscopies. Noteworthy, this templating approach successfully led to the formation of CePO4·H2O nanofibrous bundles of rather co-aligned and elongated nanofibers (10–20 nm thick and up to ca. 1 μm long). The formed nanofibers consisted of hexagonal (P6222) CePO4 nanocrystals (at 60 and 250 °C), with a better-grown and more homogeneous fibrous morphology with respect to a reference CePO4 prepared under similar (non-templated) conditions, and transformed into nanofibrous monoclinic monazite (P21/n) around 600 °C. The nanofibrous morphology was highly preserved after annealing at 900 °C under N2, although collapsed under air conditions. The nanofibrous CePO4 (as-prepared hexagonal and 900 °C-annealed monoclinic) exhibited an enhanced UV photo-luminescent emission with respect to non-fibrous homologues.

Facile one-pot construction of α-Fe2O3/g-C3N4 heterojunction for arsenic removal by synchronous visible light catalysis oxidation and adsorption

α-Fe2O3/g-C3N4 composites with heterojunction were prepared by facile one-pot synthesis using ferric chloride and dicyandiamide as precursors. The newly formed composites were applied to remove arsenic from aqueous solution for the first time through synchronous visible light catalysis oxidation and adsorption. α-Fe2O3/g-C3N4 composites were characterized by wide-angle X-ray powder diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, UV–Vis diffuse reflectance spectroscopy, and BET surface analysis. Under visible light irradiation, As(III) was oxidized to As(V) efficiently on the surface of α-Fe2O3/g-C3N4. In addition, the oxidized arsenic could be adsorbed in situ, resulting in the effective arsenic removal. The enhancement of photocatalytic activity the composites was attributed to the construction of heterojunction between α-Fe2O3 and g-C3N4. A possible oxidation mechanism of the as-composites for As(III) under visible light irradiation was also elucidated.

Piezochromic luminescence and aggregation induced emission of 9,10-bis[2-(2-alkoxynaphthalen-1-yl)vinyl]anthracene derivatives

Four derivatives of 9,10-bis[2-(2-alkoxynaphthalen-1-yl)vinyl]anthracene (BNAs) were designed, successfully synthesized and characterized by spectrofluorometer, powder wide-angle X-ray diffraction (PXRD) and differential scanning calorimetry experiments (DSC), etc. It was found that these compounds exhibited aggregation-induced emission phenomenon. Moreover, these target compounds displayed reversible color change from yellow to orange upon pressing and annealing process. Interestingly, all of BNAs obviously presented red-shifted piezofluorochromic (PFC) properties and behaved mainly length dependence of alkoxy group, in which, BNA displayed the largest PFC spectral shift (ΔlPFC=26nm). The PXRD profiles demonstrated the transformation from crystalline to amorphous state upon grinding, and the mechanism of PFC behaviors was proposed. Thus, changing the length of alkoxyl chain could be an alternative way to tune their PFC behaviors.

Influence of functionalized mesoporous silica in controlling azathioprine drug release and cytotoxicity properties

The present study is focused on functionalisation of mesoporous silica (or SBA-15) to control azathioprine drug release rate and its toxic effect. The mesoporous silica was functionalised by (γ-chloropropyl)triethoxysilicane and (3-aminopropyl)triethoxysilane (APTES) via hydrothermal process. The azathioprine was loaded into SBA-15 via post impregnation method. Azathioprine-loaded pristine and functionalised SBA-15 samples were characterised using UV–visible spectrophotometry and thermogravimetric analysis to measure the drug loading efficiency. The samples were also characterised by small and wide-angle powder X-ray diffraction, scanning electron microscope, transmission electron microscope, infrared spectroscopy and nitrogen adsorption/desorption analysis to study the structure, morphology, functionalisation and drug loading in detail. The maximum drug loading efficiency of 65(±1)% was achieved. In vitro azathioprine release profiles were studied in phosphate buffered saline (pH 7.4) and results suggested that the drug release amount could be controlled by functionalisation of carrier matrix SBA-15. Azathioprine-loaded APTES-functionalised material revealed lowest release amount of ~64.5% in 60 h. The toxicity of azathioprine was significantly reduced by loading the drug into the mesoporous pristine and functionalised silica. The controlled azathioprine release reduced its repeated administration and can reduce its toxicity and side effects. These outcomes recommend that the functionalised SBA-15 is an advantageous drug carrier for achieving extended release time.

A dipeptide-based superhydrogel: Removal of toxic dyes and heavy metal ions from waste water.

A short peptide-based molecule has been found to form a strong hydrogel at phosphate buffer solution of pH 7.46. The hydrogel has been characterized thoroughly using various techniques including field emission scanning electron microscopy (FE-SEM), wide angle powder X-ray diffraction (PXRD), and rheological analysis. It has been observed from FE-SEM images that entangled nanofiber network is responsible for gelation. Rheological investigation demonstrates that the self-assembly of this synthetic dipeptide results in the formation of mechanically strong hydrogel with storage modulus (G') around 104 Pa. This gel has been used for removing both cationic and anionic toxic organic dyes (Brilliant Blue, Congo red, Malachite Green, Rhodamine B) and metal ions (Co2+ and Ni2+ ) from waste water. Moreover, only a small amount of the gelator is required (less than 1 mg/mL) for preparation of this superhydrogel and even this hydrogel can be reused three times for dye/metal ion absorption. This signifies the importance of the hydrogel towards waste water management.

Two-Component Fluorescent-Semiconducting Hydrogel from Naphthalene Diimide-Appended Peptide with Long-Chain Amines: Variation in Thermal and Mechanical Strengths of Gels.

Two-component fluorescent hydrogels have been discovered, containing the mixtures of naphthalene diimide (NDI)-conjugated peptide-functionalized bola-amphiphile and primary amines with long alkyl chains at physiological pH 7.46. The aggregation-induced enhanced emission associated with an NDI-appended peptide in aqueous medium is rare, as water is known to be a good quencher of fluorescence. In this study, an NDI-containing gelator peptide forms a highly fluorescent aggregate in aqueous medium. Absorption and emission spectroscopic techniques reveal the formation of J-aggregates among the chromophoric moieties in their aggregated state in aqueous medium. However, this NDI-containing peptide does not form any gel in aqueous medium. In the presence of the primary amines with long alkyl chains in the buffer solution, it forms two-component fluorescent hydrogels exhibiting bright yellow fluorescence under a UV lamp (365 nm). Probably, the acid-amine interaction between the amines and the bola-amphiphile triggers the gel formation, as evident from Fourier transform infrared data, indicating the presence of a carboxylate group (-COO-) and an ammonium species (NH3+) in the coassembled two-component gel system. Low- and wide-angle powder X-ray diffraction and small-angle X-ray scattering further support the fact that the coassembled state in the gel form is produced by the supramolecular interaction between the NDI-based bola-amphiphile and the long-chain amines. Field-emission scanning electron microscopy and high-resolution transmission electron microscopy images reveal that the π-conjugated coassembled hydrogels exhibit nanofibrillar network morphologies. Interestingly, the coassembled hydrogels exhibit an enhanced fluorescence emission, excited-state lifetime, and quantum yield when compared with those of the NDI-containing amphiphile alone in its self-assembled state in aqueous medium. Moreover, the thermal stability and mechanical strength of these gels have been successfully tuned by varying the alkyl chain length of the corresponding amine. Moreover, these NDI-peptide-conjugated soft materials exhibit semiconducting behavior in their respective coassembled states. This holds future promise to use these peptide-appended NDI-based coassembled soft materials for applications in optoelectronic and other devices.

Magnetically Separated meso-g-C3N4/Fe3O4: Bifuctional Composites for Removal of Arsenite by Simultaneous Visible-Light Catalysis and Adsorption

Bifunctional mesoporous g-C3N4/Fe3O4 composites were prepared and used for the simultaneous visible-light catalysis and adsorption of arsenic from aqueous solution. The as-prepared composites were characterized by wide-angle X-ray powder diffraction, transmission electron microscopy, high-resolution transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet–visible diffuse reflectance spectroscopy, a vibrating sample magnetometer, and Brunauer–Emmett–Teller surface analysis. Experimental results showed that meso-g-C3N4/Fe3O4 composites could oxidize As(III) to As(V), which was in turn effectively removed by the composites. The photocatalytic activity was significantly enhanced by the synergistic effect between g-C3N4 and Fe3O4. In addition, a reasonable visible-light catalytic oxidation mechanism of As(III) was investigated.

NASICON type ordered mesoporous lithium-aluminum-titanium-phosphate as electrode materials for lithium-ion batteries

An ordered 2D-hexagonal mesoporous Lithium-Aluminum-Titanium-Phosphate (LATP-1) material has been synthesized by using cetyltrimethylammonium bromide (CTAB) as the structure directing agent (SDA) thorough hydrothermal route. After acid-ethanol extraction of the as-synthesized LATP-1 material, the extracted white solid product has been characterized thoroughly using small and wide angle powder X-ray diffraction (XRD), nitrogen adsorption/desorption analysis, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, field emission scanning electron microscopy (FE-SEM), Ultra-high resolution transmission electron microscopy (UHR-TEM) and thermogravimetric analysis (TGA). Elemental analysis revealed 2.53% Li, 2.02% Al, 4.84% Ti, 28.16% P, 62.44% O in the mesoporous LATP-1 material. The template-extracted LATP-1 material has been employed as anode and cathode materials for lithium ion batteries: as an anode material, the LATP-1 electrode exhibits stable discharge-charge performances with delivered capacity of 121 mAh.g−1 and 117 mAh.g−1, respectively and a high coulombic efficiency.

Improved antimicrobial property and controlled drug release kinetics of silver sulfadiazine loaded ordered mesoporous silica

The present study deals with the loading of silver sulfadiazine into ordered mesoporous silica material by post-impregnation method and its effect on the in vitro release kinetics and antimicrobial property of the drug. The formulated SBA-15 silica material with rope-like morphology and SBA-15-silver sulfadiazine (SBA-AgSD) were characterized by UV–visible spectrophotometer, small and wide-angle powder X-ray diffraction (PXRD), field emission scanning electron microscope (FESEM) and high resolution transmission electron microscope (HRTEM). Thermo-gravimetric analysis of SBA-AgSD revealed a high loading amount of 52.87%. Nitrogen adsorption–desorption analysis confirmed the drug entrapment into host material by revealing a reduced surface area (214 m2/g) and pore diameter (6.7 nm) of the SBA-AgSD. The controlled release of silver sulfadiazine drug from the mesoporous silica to simulated gastric, intestinal and body fluids was evaluated. The Korsmeyer–Peppas model fits the drug release data with the non-Fickian diffusion model and zero order kinetics of SBA-AgSD. The antibacterial performance of the SBA-AgSD was evaluated with respect to Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa. The controlled drug delivery of the SBA-AgSD revealed improved antibacterial activity, thus endorsing its applicability in effective wound dressing.

Influence of molecular weight of chitosan on the microstructures and photocatalytic property of ZrO2 prepared by chitosan templates method

ZrO2 particles with different microstructure have been fabricated through an easy method with chitosan of different molecular weights as template. The chitosan of different molecular weights was obtained through synergistic degradation of raw chitosan by α-amylase and H2O2 using microwave hydrothermal method in low concentration acetic acid (1% V/V). The as-synthesized ZrO2 particles were characterized by wide-angle powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, and N2 adsorption⿿desorption. The possible formation mechanism of ZrO2 particles with different microstructure has been proposed, and the photocatalytic activity of the as-synthesized products was assessed by monitoring the photodegradation of Rhodamine B (Rh B) under UV irradiation. Morphologies of as-synthesized ZrO2 particles changed significantly with the different molecular weight of chitosan. As the molecular weight of chitosan decreased, the morphologies of as-synthesized ZrO2 particles showed aggregate, nano-cubes, and nano-sheets, respectively. The ZrO2 particles prepared with lower molecular weight chitosan as the template showed higher photocatalytic activity. The degradation efficiency of ZrO2 with 3.1ÿ107 and 2.4ÿ104Da chitosan as template was 64.4% and 86.2%, respectively.

A Peptide-Based Mechano-sensitive, Proteolytically Stable Hydrogel with Remarkable Antibacterial Properties.

A long-chain amino acid containing dipeptide has been found to form a hydrogel in phosphate buffer whose pH ranges from 6.0 to 8.8. The hydrogel formed at pH 7.46 has been characterized by small-angle X-ray scattering (SAXS), wide-angle powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy, field-emission scanning electron microscopy (FE-SEM), high-resolution transmission electron microscopy (HR-TEM) imaging and rheological analyses. The microscopic imaging studies suggest the formation of a nanofibrillar three-dimensional (3D) network for the hydrogel. As observed visually and confirmed rheologically, the hydrogel at pH 7.46 exhibits thixotropy. This thixotropic property can be exploited to inject the peptide. Furthermore, the hydrogel exhibits remarkable antibacterial activity against Gram-negative bacteria Escherichia coli and Pseudomonas aeruginosa, which are responsible for many common diseases. The hydrogel has practical applicability due to its biocompatibility with human red blood cells and human fibroblast cells. Interestingly, this hydrogel shows high resistance toward proteolytic enzymes, making it a new potential antimicrobial agent for future applications. It has also been observed that a small change in molecular structure of the gelator peptide not only turns the gelator into a nongelator molecule under similar conditions, but it also has a significant negative impact on its bactericidal character.

Synthesis and characterisation of water dispersible copolymer submicron spheres of poly-(phenylenediamine-co-N-sulfopropyl aniline) via random copolymerisation

The homopolymers of poly-phenylenediamines (P-PD's) and poly-N-sulfopropyl aniline (PSPA) were synthesized via chemical oxidative polymerization of phenylenediamine monomers and sulfopropyl aniline using ammonium persulfate as oxidizing agent in acidified medium. Three homopolymers of phenylenediamines synthesised were poly (m-phenylenediamine) P-MPD, poly (p-phenylenediamine) P-PPD and poly (o-phenylenediamine) P-OPD. Poly-N-sulfopropyl aniline (PSPA) is a self doped water soluble conducting polymer. Random copolymerization of N-sulfopropyl aniline and phenylenediamines would enhance the solubility of the copolymer nanomaterials. Three different copolymer compositions (COP25, COP50 and COP75) were employed for copolymer synthesis based on weight percentage of co-monomer's feed taken. Homopolymers and copolymers were characterized by fourier-transform infrared spectroscopy (FT-IR) and elemental analysis. The UV–Visible absorption spectra of the samples in water were shown the characteristic polaron- π* and π−π* peaks. The solid state ordering of the samples recorded by powder wide angle x-ray diffraction studies reveals that homopolymer samples were partially crystalline, whereas copolymers were either amorphous or less crystalline than homopolymer. Morphological features of the polymers and copolymers were recorded by scanning electron microscope (SEM). Poly (m-Phenylenediamine) was present as uniformly distributed submicron spheres with an average size of 850 ± 50 nm, whereas the poly (p-phenylenediamine) was present as non-uniform spheres with size in the range 600 ± 100 nm. The P-OPD sample was highly crystalline and it has shown some ordered rod like structures. Interestingly, all copolymer samples like M-COP25, P-COP25, and O-COP25 were formed as uniform submicron spheres. Poor water solubility of poly-phenylenediamines in aqueous solution was increased tremendously upon copolymerization.

Semiflexible thermotropic polyazomethines based on o-dianisidine mesogenic core

A new series of thermotropic polyazomethines (PAMs) containing flexible spacers in the main chain and side methoxy groups on the mesogenic core has been synthesised by solution polycondensation reaction of o-dianisidine with α,ω-bis(4-formylphenoxy)-alkanes. A model compound was also synthesised by condensation reaction of o-dianisidine with p-butoxybenzaldehyde, in order to accomplish the structural characterisation and for a better understanding of the polymer properties. Chemical structure of the studied polymers was confirmed by Fourier transform infrared spectroscopy and proton nuclear magnetic resonance spectroscopy, and the supramolecular organisation was determined by powder wide angle X-ray diffraction measurements. The thermal properties of the polymers and model compound were investigated by thermogravimetry, polarised light microscopy and differential scanning calorimetry. The resulting data indicated high thermostability without significant weight loss up to 380°C and nematic liquid crystalline behaviour with large stability range (around 100°C) of the mesophase. Electronic UV–Vis absorption and light emitting ability were also investigated; these PAMs presented broad emission bands in the blue domain.

Thermally mendable material based on a furyl-telechelic semicrystalline polymer and a maleimide crosslinker

Based on Diels-Alder reaction, a furyl-telechelic semicrystalline polycaprolactone was crosslinked by a tris-maleimide crosslinker. The synthesized precursors and network were fully characterized via proton nuclear magnetic resonance (1H NMR) and Fourier transform infrared (FT-IR) spectroscopies, gel permeation chromatography (GPC), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and wide-angle powder X-ray diffraction (XRD) measurements. The obtained material showed mendability of scratches under thermal treatment, as evidenced by optical microscopy and tensile analysis. The mending process was a combination of the shape recovery effect favoring scratch closure and the re-crosslinking of the cleaved Diels-Alder bonds at temperatures slightly above the melting transition of polycaprolactone chains. A scratch healing efficiency determined by tensile tests of about 70 % was achieved.

Dielectric silicone elastomers with mixed ceramic nanoparticles

A ceramic material consisting in a zirconium dioxide-lead zirconate mixture has been obtained by precipitation method, its composition being proved by wide angle X-ray powder diffraction and energy-dispersive X-ray spectroscopy. The average diameter of the ceramic particles ranged between 50 and 100nm, as revealed by transmission electron microscopy images. These were surface treated and used as filler for a high molecular mass polydimethylsiloxane-α,ω-diol (Mn=450,000) prepared in laboratory, the resulted composites being further processed as films and crosslinked. A condensation procedure, unusual for polydimethylsiloxane having such high molecular mass, with a trifunctional silane was approached for the crosslinking. The effect of filler content on electrical and mechanical properties of the resulted materials was studied and it was found that the dielectric permittivity of nanocomposites increased in line with the concentration of ceramic nanoparticles.

Effects of montmorillonite and compatibilizer on the mechanical and thermal properties of dispersing intercalated PMMA nanocomposites

We added montmorillonite (MMT) to improve the mechanical properties and thermal stability of poly (methyl methacrylate) (PMMA). We used a twin-screw extruder to produce standard specimens for examinations. We examined the layer distance of MMT and mechanical properties of the nanocomposites containing various amounts of MMT. The chemical structure and morphology of specimens were characterized with wide-angle powder X-ray diffraction, scanning, and transmission electron microscopy techniques. It was observed that by increasing the amount of MMT, layer distance increased from 2.16 to 3.87nm for the composite containing 5 wt% MMT. In the tensile and impact properties examinations, the composite containing 1% MMT revealed the best result with increase of 1.81%. The shore hardness and wear resistance properties were also significantly improved. The beginning of thermal decomposition of nanocomposites slightly shifted to a higher temperature, compared with the thermogram of pure PMMA.

Synthesis of MgO nanoparticle loaded mesoporous Al2O3 and its defluoridation study

MgO nanoparticle loaded mesoporous alumina has been synthesized using a simple aqueous solution based cost effective method for removal of fluoride from water. Wide angle powder X-ray diffraction, nitrogen adsorption desorption analysis, transmission electron microscopy techniques and energy dispersive X-ray spectroscopy were used to characterize the synthesized adsorbents. Synthesized adsorbents possess high surface area with mesoporous structure. The adsorbents have been thoroughly investigated for the adsorption of F− using batch adsorption method. MgO nanoparticle loading on mesoporous Al2O3 enhances the F− adsorption capacity of Al2O3 from 56% to 90% (initial F− concentration=10mgL−1). Kinetic study revealed that adsorption kinetics follows the pseudo-second order model, suggesting the chemisorption mechanism. The F− adsorption isotherm data was explained by both Langmuir and Freundlich model. The maximum adsorption capacity of 40MgO@Al2O3 was 37.35mgg−1. It was also observed that, when the solutions having F− concentration of 5mgL−1 and 10mgL−1 was treated with 40MgO@Al2O3, the F− concentration in treated water became <1mgL−1, which is well below the recommendation of WHO.

Periodic order and defects in Ni-based inverse opal-like crystals on the mesoscopic and atomic scale

Thestructureofinverseopalcrystalsbasedonnickelwasprobedonthemesoscopicandatomiclevelsbyasetof complementary techniques such as scanning electron microscopy and synchrotron microradian and wide-angle diffraction. The microradian diffraction revealed the mesoscopic-scale face-centered-cubic (fcc) ordering of spherical voids in the inverse opal-like structure with unit cell dimension of 750 ± 10 nm. The diffuse scattering data were used to map defects in the fcc structure as a function of the number of layers in the Ni inverse opal-like structure. The average lateral size of mesoscopic domains is found to be independent of the number of layers. 3D reconstruction of the reciprocal space for the inverse opal crystals with different thickness provided an indirect study of original opal templates in a depth-resolved way. The microstructure and thermal response of the framework of the porous inverse opal crystal was examined using wide-angle powder x-ray diffraction. This artificial porous structure is built from nickel crystallites possessing stacking faults and dislocations peculiar for the nickel thin films.