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We report the growth and characterization of coexistence of vertically aligned and twinned V-shaped RuO2 nanorods (NRs). The well-aligned RuO2 NRs were grown on top of rutile (R) phase TiO2 NRs sitting on sapphire (SA) (1 0 0) substrate via metal-organic chemical vapor deposition (MOCVD) by using bis(ethylcyclopentadienyl) ruthenium (II) and titanium-tetraisopropoxide (TTIP, Ti[OCH(CH3)2]4) as source reagents. The surface morphology, structural, and spectroscopic properties of the as-deposited nanocrystals (NCs) were characterized by field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), micro-Raman spectroscopy, transmission electron microscopy (TEM) and selected-area electron diffractometry (SAED). The FESEM images and XRD patterns indicated growth of vertically aligned RuO2(0 0 1) and V-shaped RuO2(1 0 1) NRs on top of R-TiO2 NRs. The Raman spectrum indicated the formation of high quality RuO2 NCs on rutile phase of TiO2 NRs. TEM and SAED characterizations of V-shaped RuO2 NRs showed that the nanorods were crystalline RuO2 with a twin plane of (1 0 1) and twin direction of [ 1 ¯ 0 1 ] at the V-junction. The probable mechanisms for the formation of well-aligned RuO2 NRs are discussed.

Carbon nanofibers (CNFs) were grown in the porous anodic aluminum oxide (AAO) thin film grown on the Si wafer by electron cyclotron resonance chemical vapor deposition using cobalt as the catalyst. A larger Co particle electrodeposited in the AAO pore channel produced vertically aligned CNFs with a tube diameter in compliance with the pore size of the AAO template. On the other hand, a smaller Co particle resulted in CNF growth with a nonuniform distribution of the tube diameter and a sparse tube density. Amorphous carbon residue produced under the plasma-assisted CNF growth condition seemed to play an essential role leading to the observation. A growth mechanism is proposed to delineate the volume effect of the electrodeposited Co catalyst on the CNF growth confined in pore channels of the AAO template.

We demonstrate here that ZnS nanotubes can be successfully synthesized via a facile conversion process from ZnO nanorods precursors. During the conversion process, ZnO nanorods are first prepared as sacrificial templates and then converted into tubular ZnO/ZnS core/shell naonocomposites through a hydrothermal sulfidation treatment by using thioacetamide (TAA) as sulfur source. ZnS nanotubes are finally obtained through the removal of ZnO cores of tubular ZnO/ZnS core/shell naonocomposites by KOH treatment. The photoluminescence (PL) characterization of the as-prepared products shows much enhanced PL emission of tubular ZnO/ZnS core/shell nanocomposites compared with their component counterparts. The probable mechanism of conversion process is also proposed based on the experimental results.

Terbium (III)-doped yttrium oxysulfate Y2O2SO4:Tb3+ was synthesized by the 1000 °C calcination of Tb3+-doped dodecylsulfate-templated yttrium oxide mesophases with straight-layered (S-type) and concentric-layered (C-type) structures. The Tb3+-doped oxysulfates exhibited luminescence bands including the 5D4–7F5 transition with a tendency in intensity to saturate or reach a maximum at 13–25 mol% Tb doping. The maximum intensity of Tb3+ emission for the C-type-mesophase-mediated Y2O2SO4:Tb3+ was 1.44 times stronger than that for the S-type-mesophase-mediated analogues, although the Eu3+ emissions for C-type-mesophase-mediated Y2O2SO4:Eu3+ was enhanced in intensity up to three times stronger than those for S-type-mesophase-mediated ones. It is suggested from FT-IR data that any specific deformation of sulfate groups is induced for both emission systems by the conversion of concentric dodecylsulfate-layers into straight sulfate-layers in the oxysulfate framework upon calcination. This leads to the enhanced emission for the Eu3+-doped system, whereas the emission of Tb3+ in the same Y2O2SO4 matrix is slightly enhanced because the electronic state of 4f8 for Tb3+ ion is insensitive to the change of the distribution of the surrounding negative-charged oxide ions.

Three-dimensional (3D) SiO 2 has been prepared by coating silica on the surface of a template polymer and a sequent calcination of the silica/polymer composite. The template polymer that has 3D skeletal structure was prepared by curing epoxy resin in polyethylene glycol mediums using diethylenetriamine as a curing agent. The coating of silica on the polymer surface was accomplished through a slow in situ hydrolysis of infiltrated ethyl silicate in the interconnected pore network of the template polymer. The thickness of silica layer was controlled in a range of 20–80 nm by changing the total amount of ethyl silicate in hydrolysis. The 3D structures of silica were characterized by scanning electronic microscopy, transmitting electronic microscopy, Fourier transform infrared spectroscopy and surface area measurement. The light scattering of the 3D silica filled with liquid medium can be minimized by tuning the refractive index of the liquid medium to be the same as that of amorphous silica in the 3D structure.

Nd-substituted bismuth titanate (Bi3.15Nd0.85Ti3O12, BNT) nanotube arrays are fabricated by means of a sol–gel method utilizing porous anodic aluminum oxide (AAO) template. The morphologies and structures have been determined by scanning electron microscopy (SEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The diameter and length of these nanotubes are about 200 nm and 60mm, respectively, and their wall thickness is about 30 nm. The average grain size is around 40 nm. XRD data show that the BNT nanotubes possess bismuth-layered perovskite structure. High-resolution electron microscopy (HRTEM) image demonstrates that the BNT nanotubes are polycrystalline. Polarization–electric field (P–E) response curves of BNT nanotube arrays were measured, and a size induced polarization reduction phenomenon is observed.

The transformation of Te nanotubes to CoTe 2 nanotubes have been achieved through a solvothermal process in a mixed solvent of ethylene glycol (EG) and oleic acid (OA) at 200 °C for 24 h. Single crystalline Te nanotubes generated in situ could serve as the Te source and template, and then transformed as self-assembly CoTe 2 nanotubes. In the unique reaction system, CoTe 2 nanotubes were obtained when the volume ratio of EG and OA ( V EG / V OA ) was 5/3. The facile approach was extended to prepare other 1D telluride nanostructures, including CdTe, PbTe, Sb 2 Te 3 and Bi 2 Te 3 .

Highly ordered mesoporous crystalline MoO(2) materials with bicontinuous Ia3d mesostructure were synthesized by using phosphomolybdic acid as a precursor and mesoporous silica KIT-6 as a hard template in a 10% H(2) atmosphere via nanocasting strategy. The prepared mesoporous MoO(2) material shows a typical metallic conductivity with a low resistivity ( approximately 0.01Omega cm at 300 K), which makes it different from all previously reported mesoporous metal oxides materials. Primary test found that mesoporous MoO(2) material exhibits a reversible electrochemical lithium storage capacity as high as 750 mA h g(-1) at C/20 after 30 cycles, rendering it as a promising anode material for lithium ion batteries.

A novel manganese phosphite-oxalate, [C2N2H10][Mn2II(OH2)2(HPO3)2(C2O4)] has been hydothermally synthesized and its structure determined by single-crystal X-ray diffraction. The structure consists of neutral manganese phosphite layers, [Mn(HPO3)]∞, formed by MnO6 octahedra and HPO3 units, cross-linked by the oxalate moieties. The organic cations occupy the middle of the 8-membered one-dimensional channels. Magnetic studies indicate weak antiferromagnetic interactions between the Mn2+ ions.

A systematic investigation on the Ag/bpy/(H)dpa family represents seven Ag(I) supramolecular compounds with distinct structural features, Ag2(bpy)0.5(dpa) (1), Ag2(bpy)1.5(dpa)(H2O) (2), Ag(bpy)0.5(Hdpa) (3), α-[Ag(bpy)]·(Hdpa) (4), β-[Ag(bpy)]·(Hdpa) (5), [Ag(bpy)]2·(dpa)·6(H2O) (6), and [Ag(bpy)]4·(dpa)·2(NO3)·6(H2O) (7) (H2dpa = 1,1′-biphenyl-2,2′-dicarboxylic acid, bpy = 4,4′-bipyridine). Of particular interest about this work is that supramolecular isomerism is observed between compounds 4 and 5. Single-crystal X-ray structural analysis reveals the structural diversity of the formed products. Compounds 1−5 are extended from various one-dimensional (1D) chain substructures. Three distinct 1D chains exist in 1−3: one 1D chain of {Ag2(dpa)} exists in compound 1, one supramolecular chain of tetranuclear {Ag2(dpa)(H2O)}2 subunits linked by Ag···Ag interactions (argentophilic interactions) and hydrogen bonding interactions is observed in 2, and one 1D alternate chain of eight-membered {Ag2(Hdpa)2} ring bri...

Large-scale arrays consist of dendritic single-crystalline Ag/Pd alloy nanostructures are synthesized for the first time. A simple galvanic replacement reaction is introduced to grow these arrays directly on Ag substrates. The morphology of the products strongly depended on the reaction temperature and the concentration of H2PdCl4 solution. The mechanism of the formation of alloy and the dendritic morphology has been discussed. These alloy arrays exhibit high surface-enhanced Raman scattering (SERS) activity and may have potential applications in investigation of “in situ” Pd catalytic reactions using SERS. Moreover, electrocatalytic measurements suggest that the obtained dendritic Ag/Pd alloy nanostructures exhibit electrocatalytic activity toward the oxidation of formic acid.

Crystallization of the active pharmaceutical ingredient Entacapone, which exhibits strong polymorphic behavior in aqueous/acetone solutions, is examined with and without the presence of a self-assembled molecular layer of Entacapone (SALE) on an Au (100) surface. SALE characterization by electrochemical and spectroscopic tools confirms the existence of a well-ordered layer structure. These surfaces are found to act as nucleation catalysts providing polymorph-specific templates which enable secondary nucleation through provision of oriented adsorption and molecular recognition at the SALE/solution interface. In particular, crystallization of the stable prismatic polymorphic form A is observed from aqueous/acetone solutions in the presence of an SALE compared to needle-shaped crystals of the metastable form D which usually form. The quiescent crystallization of Entacapone from the same aqueous/acetone solutions in the presence of an Au (100) surface produces an assembly of single crystals form A epitaxially...

1D nanostructures of Zn1−xCoxO (x = 0, 0.03 and 0.05) and Co and Li codoped ZnO (Zn0.85Li0.10Co0.05O) were prepared by a soft chemical method. We report a very interesting observation of morphological control and transformation of ZnO nanorods to spherical particles induced by Co substitution. It is also remarkable to note that the morphology completely reverts back to rod shape by Li incorporation. In addition to this unusual observation, the Li incorporation enhances the room-temperature ferromagnetic (RTFM) properties. These experimental observations are well-supported by theory work as well. These results are significant, as the 1D RTFM will have implications in spintronic devices.

MnO2 with different crystallographic forms (α, γ) and morphologies (needles, rods, and spindles) was fabricated via a facile quick-precipitation procedure at a low temperature (about 83 °C) without using any templates or surfactants. The proposed mechanism is focused on the different reaction parameters that affect the behaviors of MnO6 octahedron units (basic structural framework of MnO2), which then exert an influence on the formation and stack of nuclei in the crystal growth process. Specific capacitances (Cs) calculated according to the area of the cyclic voltammograms (CV) curves were 233.5, 83.1 F·g−1 for the needle- and 95.5, 29.3 F·g−1 for the spindle-like products at the scan rate of 5, 100 mV·s−1, respectively. The Cs of needle-like samples calculated by discharge curves at the current density of 2 mA·cm2 is 209.8 F·g−1, close to the value calculated by CV curves at the scan rate of 5 mV·s−1. This methodology facilitates us to synthesize MnO2 with discrepant one-dimensional (1D) nanostructures v...

Perpendicularly aligned semiconducting CdSe nanorod arrays were fabricated on ITO-coated glass substrate using porous aluminum oxide (PAO) as a hard template. Nanorod lengths were varied between 50 and 500 nm, while keeping the diameter at 65 nm. The electrochemical photovoltaic performance was found to depend critically on nanorod length and crystallinity. Arrays of rods annealed at 500 degrees C showed an order of magnitude improvement in white light power conversion efficiency over unannealed samples. The largest power conversion efficiency of 0.52% was observed for nanorods 445 +/- 82 nm in length annealed at 500 degrees C. The technique described is generally applicable to fabricating highly aligned nanorods of a broad range of materials on a robust transparent conductor.

Molten hydrated salt was used, for the first time, as a new kind of solvent to explore the synthesis of complex oxide nanomaterials. Employing Ba(OH)23 8H2O as the solvent, and rutile TiO2 as the reactant, core-shell and hollow nanoparticles of perovskite-type BaTiO3 were successfully fabricated under sealed conditions at 180 C. No other additive was introduced into the reaction system. The effect of various reaction conditions on the morphology and size of the products was investigated. At high TiO2 dosage, core-shell BaTiO3 particles were the dominant products with their sizes between 400 and 800 nm, whereas relatively low TiO2 dosage favored the formation of hollow BaTiO3 particles less than 250 nm. The formation process of the products was investigated, and can be attributed to an Ostwald ripening induced hollowing mechanism. Because of its simplicity and scalability, the molten hydrated salt method may open up a promising route for the synthesis of complex oxide micro/nanomaterials for practical applications.

The reversible molecular template-directed self-assembly of gold nanoparticles (AuNPs), a process which relies solely on noncovalent bonding interactions, has been demonstrated by high-resolution transmission electron microscopy (HR-TEM). By employing a well-known host-guest binding motif, the AuNPs have been systemized into discrete dimers, trimers, and tetramers. These nanoparticulate twins, triplets, and quadruplets, which can be disassembled and reassembled either chemically or electrochemically, can be coalesced into larger, permanent polygonal structures by thermal treatment using a focused HR-TEM electron beam.

Highly ordered array of hierarchical nanotubes constructed from Cu2O hollow nanospheres with a diameter of 165−185 nm and shell thickness of 20−40 nm has been synthesized by using an array of Cu(OH)2 nanorods as a sacrificial template. The formation of Cu2O nanotubes is considered to be the result of the “Kirkendall effect”, while evolution of the Cu2O hollow nanospheres from solid nanospheres in the walls results from the “Ostwald ripening” process. Furthermore, the Kirkendall effect in nanoscaled synthesis has been directly proven by the successful design and synthesis of arrays of Cu2O/Cu2−xSe heterogeneous nanotubes constructed from Cu2O hollow seminanospheres covered on both the inner and the outer surfaces of Cu2−xSe sheaths with a thickness about 5−10 nm, in which the diffusion rate of copper ions through the Cu2−xSe sheaths is shown to be double that of ascorbic acid molecules during the reaction process. This work offers a new strategy to study the diffusion rate relationship between diffusion co...

We report the first use of a block terpolymer for the synthesis of three-component nanocomposites. Here, the use of three chemically distinct polymer blocks enabled control over each of the three final components: partially graphitic carbon, crystalline transition metal oxide, and porosity. Tuning of the individual block lengths and block fractions resulted in control over the three components. Specifically, two PAN-b-PEO-b-PPO-b-PEO-b-PAN pentablock terpolymers were synthesized starting with a functionalized P123 or F127 macroinitiator. The PEO blocks were selectively swelled with titania sols while the PPO primarily served as a mesoporosity source and the PAN served as a carbon source with high yield. Two subsequent heat treatments were used to form partially graphitic carbon which acted as an in situ hard template preserving the mesostructure through the crystallization of the titania sols. TEM and SAXS analysis revealed wormlike microphase separation. Nitrogen physisorption analysis revealed that the ...

Monodisperse hexagonal Ln(OH)(3) (Ln = Eu, Sm) submicrospindles with uniform morphology and size have been Successfully synthesized in a large scale via a Facile aqueous solution route from the mixture of aqueous solutions or LnCl(3) and NaOH at 5 degrees C without using any surfactant or template. The as-synthesized products are characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), energy-dispersive X-ray (EDX) spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). The SEM and TEM images show that the as-formed Ln(OH)(3) samples have a spindlelike shape with an equatorial diameter of 80-200 nm and a length of 500-900 nm, which are aggregates of even smaller nanoparticles.

Atomic force microscopy was used to study the surface of STA-7 crystals. STA-7 is a silicoaluminophosphate, nanoporous solid formed by interlinked double six ring units (D6R). Observations showed the formation of three distinct types of spirals at low supersaturation conditions. The {001} face shows spirals with isotropic shapes and a Burgers vector of 0.9 nm, which corresponds to one D6R or one unit cell along the ⟨001⟩ direction. The {100} face contains two distinct types of spirals. The first has a Burgers vector of 0.9 nm, or half a unit cell along ⟨100⟩. This dislocation produces a change in the “stacking” sequence of the D6Rs generating an overgrowth with the AEI structure. The second type is an interlaced spiral and is generated by a dislocation with a Burgers vector of 1.8 nm or one unit cell, leading to the formation of two substeps each with a different growth anisotropy. This anisotropy is directed by the shape of the substep and the energetics of template attachment. The preponderance of a sur...

A novel method was used to synthesize CdS single-crystal nanorods directly in the presence of conjugated polymer poly(3-hexylthiophene-2,5-diyl) (P3HT), where the P3HT is acting as a molecular temp...

We have prepared silver nanoparticles on the surface of bacterial cellulose (BC) nanofibers. The synthesis of silver nanoparticles incorporates 2,2,6,6-tetramethylpiperidine-1-oxyradical (TEMPO)-mediated oxidation to introduce carboxylate groups on the surface of BC nanofibers. An ion exchange of the sodium to the silver salt was performed in AgNO(3) solution, followed by thermal reduction. By using oxidized BC nanofibers as a reaction template, we have prepared stable silver nanoparticles with a narrow size distribution and high density through strong ion interactions between host carboxylate groups and guest silver cations, which have been investigated by scanning electron microscopy, UV-visible spectroscopy, and a small-angle X-ray scattering method.

In acetonitrile, reactions of bis(acetylacetonato)oxidovanadium(IV) ([VO(acac) 2 ]) with 4- R -benzoylhydrazine in 1:1 mole ratio provide coordinatively symmetrical complexes ( 1 – 5 ) of the {OV(μ-O)VO} 4+ motif in 40–47% yields. On the other hand, in methanol the same reactants provide complexes ( 6 – 10 ) containing the {OV(μ-OMe) 2 VO} 4+ core in 37–50% yields. In both series of complexes, the ligand is the O,N,O-donor deprotonated Schiff base system 4- R -benzoic acid (1-methyl-3-oxo-butylidene)-hydrazide formed by template condensation of acac − with 4- R -benzoylhydrazine (R = H, Cl, OMe, NO 2 and NMe 2 ). All the complexes have been characterized by elemental analysis, magnetic and spectroscopic (IR, UV–Vis and NMR) measurements. Molecular structures of three representative complexes ( 4 , 6 and 7 ) have been determined by X-ray crystallography. In each complex, the dianionic planar ligand is coordinated to the metal centre via the enolate-O, the imine-N and the O-atom of the deprotonated amide functionality. Cyclic voltammetric measurements in dichloromethane revealed that complexes 1 – 5 are redox inactive, while complexes 6 – 10 display a metal centred reduction in the potential range −0.06 to 0.0.32 V (versus Ag/AgCl).

Applying both template and Si cap technology, we achieved the epitaxial growth of CoSi 2 directly on Si(1 0 0) substrate by rapid thermal annealing (RTA). The crystal quality of CoSi 2 film is found to be significantly dependent on the Si cap thickness. In our work, a good-quality CoSi 2 film with a minimum of χ min ~11.6% and 3.3 Ω/square was obtained as a 15 nm Co with a subsequent 15 nm Si cap layer is deposited on an oxide-mediated CoSi 2 template and followed by an anneal at 1050 °C under N 2 protection; whereas too thin or thick Si cap layer will deteriorate the crystalline quality of CoSi 2 . These experimental results are discussed in combination with the simulation of Rutherford backscattering spectroscopy and X-ray reflectivity.

Using Zn nanowires as a self-sacrificed template, hierarchical tubes constructed by zinc oxide (ZnO) nanoflakes and ZnO nanotubes have been successfully fabricated by two different thermal-oxidation modes. The products were characterized by the X-ray powder diffraction, transmission electron microscopy and field-emission scanning electron microscopy. The experimental results show that the formation processes of ZnO nanostructures are sensitive to the growth temperature, which is lower or higher the melting point of Zn (419 °C). ZnO nanoflake tubes and ZnO nanotubes can be controlled through the variation of the heat-treatment process of Zn nanowires and their growth pathway can be described by two types of growth mechanism, in terms of Kirkendall effect and the sublimation of the Zn cores, respectively. Our method provides an easy and convenient way to prepare metal oxides tubular nanostructures with different morphologies through self-sacrificed template method via adjusting the heat-treatment process.

High surface area pure mesoporous aluminum-phosphorus oxide-based derivatives have been synthesized through an S+I− surfactant-assisted cooperative mechanism by means of a one-pot preparative procedure from aqueous solution and starting from aluminum atrane complexes and phosphoric and/or phosphorous acids. A soft chemical extraction procedure allows opening the pore system of the parent as-prepared materials by exchanging the surfactant without mesostructure collapse. The nature of the pore wall can be modulated from mesoporous aluminum phosphate (ALPO) up to total incorporation of phosphite entities (mesoporous aluminum phosphite), which results in a gradual evolution of the acidic properties of the final materials. While phosphate groups in ALPO act as network building blocks (bridging Al atoms), the phosphite entities become basically attached to the pore surface, what gives practically empty channels. The mesoporous nature of the final materials is confirmed by X-ray diffraction (XRD), transmission electron microscopy (TEM) and N2 adsorption–desorption isotherms. The materials present regular unimodal pore systems whose order decreases as the phosphite content increases. NMR spectroscopic results confirm the incorporation of oxo-phosphorus entities to the framework of these materials and also provide us useful information concerning the mechanism through which they are formed.

Bimodal macro-mesoporous silica networks have been prepared in a simple one-pot synthesis using an inexpensive tetramine surfactant and tetraethoxysilane as a silica precursor. These novel materials show high pore volumes and templated mesopores (average pore size 3.0 nm) embedded in 20 nm thick walls forming interparticle large meso/macropores. The judicious control of the pH during the silica formation allows for the precise control of the interparticle condensation, likely due to the change in the interaction between the tetramine surfactant and the silica precursors. Finally, a highly porous carbon replica with bimodal porosity was prepared by using the bimodal silica as a hard sacrificial template. The microstructure of the silica template was accurately transferred to the carbon material obtaining high surface areas (up to 1300 m{sup 2} g{sup -1}) and total pore volumes >=2 cm{sup 3} g{sup -1}. - Graphical abstract: Hierarchical bimodal porous silica and its carbon replica prepared by nanocasting.

Mesoporous nanocrystalline titania (nc-TiO 2 ) films were synthesized by sol–gel route using poly (alkylene oxide) block copolymer as template and tetrabutyl orthotitanate as titanium source. Influence of acetylacetone (AcAc), glacial acetic acid, HCl and AcAc-HCl as inhibitors on hydrolysis/condensation reaction was investigated. The mesopore structure, crystalline phase and optical characteristics were analyzed by N 2 adsorption, X-ray diffraction, transmission electron microscopy and UV–VIS–NIR spectrum. Photoaction measurements were performed on dye-sensitized solar cells (DSSCs) using the mesoporous nc-TiO 2 as photoanodes. The results show that the formed films are anatase phase and mesoporous structure. Different restraining mechanisms of these inhibitors to hydrolysis/condensation process lead to different mesoporous structure whose specific surface area (S BET ) varies from 34 to 176 m 2 /g, and crystal size is from 5.6 to 38.2 nm. The mesoporous photoanode with high S BET and large crystalline grains may be responsible for increasing conversion efficiency of the DSSCs.

Uniform octahedral YVO4:Eu3+ microcrystals have been successfully prepared through a designed two-step hydrothermal conversion method. One-dimensional precursor Y4O(OH)9NO3 was first prepared through a simple hydrothermal process without using any surfactant, catalyst or template. Subsequently, well-defined octahedral YVO4 was synthesized at the expense of the precursor during a hydrothermal conversion process. XRD results demonstrate that the diffraction peaks of the final product can be well indexed to the pure tetragonal phase of YVO4. The SEM and TEM images indicate that the as-prepared YVO4 sample has regular octahedral shape with sharp corners and well-defined edges. The as-obtained YVO4:Eu3+ phosphor shows strong red emission under ultraviolet excitation or low-voltage electron beam excitation. Furthermore, this facile and general conversion method may be of much significance in the synthesis of many other lanthanide compounds with uniform morphology.

Loading or filling nanostructures with antibiotics can be one of the relevant approaches for obtaining a controlled drug release rate. Vertically aligned silicon nanowire (SiNW) arrays with 10-40 nm diameter wires having 1-3 microm in length obtained by the electroless etching (EE) technique are used in this study as novel nanostructures for mediating drug delivery. Here we report controlled antibiotic activity and sustained bioavailability from SiNW arrays and also show microstructural manipulations for a tunable release rate. As well, we have demonstrated biodegradability of SiNWs in phosphate buffer saline (PBS) solution. Strikingly suppressed cell and protein adhesion was observed on our SiNW surface, which indicates a reduced probability for biofouling and drug release impediments. Such antibiotic release from the nanowire-structured surface can provide more reliable antibiotic protection at a targeted implantation or biosensor site.

Organic laser dyes coumarin 1, coumarin 2, coumarin 102, coumarin 314, and coumarin 334 have been included in crystalline guanidinium organodisulfonate (GDS) host frameworks, forming stable inclusion compounds with lamellar architectures. The GDS hosts consist of 2D quasihexagonal hydrogen-bonded sheets with topologically complementary guanidinium (G) ions and the sulfonate (S) moieties of a variety of organodisulfonates that serve as “pillars” that connect opposing GS sheets, thus generating inclusion cavities between the sheets. These host frameworks display a variety of architectural isomers, including the so-called bilayer, simple brick, zigzag brick as well as two heretofore unreported framework isomers: double zigzag brick and a “chevron” brick. These isomers vary with respect to the connectivity between opposing GS sheets and the corresponding shape of the inclusion cavities. The preference for the framework isomers reflects a systematic templating role for the guest molecules, largely based on the...

Uniform 5 μm Bi2S3 microspheres and 8 μm microflowers were solvothermally synthesized in acetylacetone solution through thermolysis of the Bi3+-dithizone complex without any templates or surfactants. Bi2S3 microspheres composed of nanorods with a diameter of 20−40 nm were synthesized at 180 °C for 12 h. In similar conditions at 240 °C for 3 days, microflowers composed of nanowires with lengths up to several micrometers and diameter of 20−40 nm were obtained. Field-emission scanning electron microscopy (FESEM) showed in the initial stage in the formation process that smooth spherical cores were observed, then on the surface of the cores nanoparticles appeared, and finally nanorods or nanowires grew out and microspheres and microflowers formed. Electrochemical experiments using Bi2S3 in a lithium ion battery indicated that the first discharge capacity of Bi2S3 microflowers could reach about 148 mA h g−1.

Molecular templating in the sol–gel process represents a unique approach in production of uniform particles efficient as parts of sensors and other electrochemical devices. Major focus of this work was to produce a series of TiO2 thin films under otherwise constant conditions, but varying the molecular structure of the templates, and then relate these structural differences with electrochemical characteristics of the layers. This knowledge might be of practical importance in the design of optimised films for photo-responding sensors. The molecular template provides a reaction space, but also the basic particulate structure. It was demonstrated that templates from the family of non-ionic surfactants with variable lengths of hydrophilic chains may significantly affect the photoinduced electrochemical responses of the produced particles. Special attention was paid to the detailed structural and morphological description of the produced films. The key point of the study, the functional characterisation, was arranged as evaluation of the photoexcitation properties of the films with help of cyclic voltammetry, linear voltammetry, amperometry and open circuit potential measurements. It must be noted that these functional properties were clearly identified to be dependent on the structure of the templating molecules.

We report a simple and cost-effective double templating method for fabricating large-area three-dimensional metallic photonic crystals of controlled thickness. A self-assembled polystyrene opal was used as the first template to fabricate a silica inverse opal on a gold-coated glass substrate via sol-gel processing. Gold was subsequently infiltrated to the pores of the silica inverse opal using electrochemical deposition. A high-quality three-dimensional gold photonic crystal was obtained after removal of the secondary template (silica inverse opal). The effects of template sphere size and deposition current density on the gold growth rate, and the resulting morphology and growth mechanism of the gold opal, were investigated. � 2009 Elsevier B.V. All rights reserved.

The synthesis of large-scale one-dimensional silica nanotube (SNT) arrays embedded in Si substrate is demonstrated by using the combination of AAO template mask and Ar ion milling technique. The geometry of the SNTs could be precisely controlled by the process parameters, which included that the SNT diameter and the interpore distance were controlled by AAO anodization voltage and H 3 PO 4 pore widening time, while the length of SNT was controlled by ion milling time and AAO aspect ratio. Also, the SNT fabrication parameters could be related to their photoluminescence (PL) emitting properties, when anodized at 40 V, pore widening in H 3 PO 4 acid for 70 min and ion milled for 5 min, a strong intensity and stable ultraviolet (UV) light of 3.25 eV (381 nm) emitted from the SNTs under the excitation of 266 nm laser, which could be assumed arising from twofold coordinated silicon lone pair centers in the oxygen deficiency SNTs. The present fabrication of SNT arrays presents a novel method for intensity and frequency adjustable ultraviolet optoelectronic devices.

Ab initio supercell calculations employing the periodic Hartree–Fock formalism are presented of the (0001) α-Cr2O3 surface with a partially or totally Al-substituted external layer. In the simulations a fraction of the Cr atoms at the surface of the chromia slab are replaced by Al atoms, and the Al surface coverage is varied between zero (pure chromia) and 100% (Al-terminated chromia). The surface Al atoms are found to relax inwards considerably, with the magnitude of the relaxation decreasing with increasing Al surface coverage. The calculations also reveal that the surface energy of the slab decreases with increasing Al coverage. Finally, the electronic properties at the surface of the Al-substituted (0001) α-Cr2O3 slabs are investigated. Here the calculations show that the substitution of Cr by Al gives rise to an increase in the covalency of the Al O bonds compared to slabs of pure alumina. In contrast, the influence of the surface Al atoms on the electrostatic potential in the (0001) plane of metal ions is relatively small. These findings support the utilisation of α-chromia substrates for the templated growth of α-alumina, which is consistent with recent experiments.

A three-dimensional ordered polyoxometalate periodic film was synthesized using dodecatungstophosphoric acid (H{sub 3}PW{sub 12}O{sub 40}) and Cs{sub 2}CO{sub 3} as precursors and colloidal crystals as templates by an inverse opal method. The samples were characterized by elemental analysis, XRD, IR spectra, UV-Vis diffuse reflectance spectra (DR-UV-Vis) and SEM techniques. This arrayed film constructed by pure cesium salt of dodecatungstophosphoric acid Cs{sub 2.5}H{sub 0.5}PW{sub 12}O{sub 40} nanoparticles shows well-defined lamellar array with inverse opal structure, which exhibits a well-defined photonic band gap. - Graphical abstract: A three-dimensional ordered Cs{sub 2.5}H{sub 0.5}PW{sub 12}O{sub 40} periodic film was synthesized by an inverse opal method using H{sub 3}PW{sub 12}O{sub 40} and Cs{sub 2}CO{sub 3} as precursors via nanocasting route and colloidal crystal as template (all scale bars are 1 {mu}m).

Poly(styrene-alt-maleic anhydride) (SMA) self-assembles in aqueous solution to form nanotube structures. These can be used as templates to linearly guide the growth of a secondary polymeric or inorganic material. Templates are made starting from a basic SMA solution, followed by slow pH decrease by dialysis against deionized water, until a 50% degree of protonation is reached. The nanotube structure is composed of multiple polymer chains, associating sideways by π-stacking to form the nanotube walls. The SMA templates were used to grow linear composites, which shows the applicability of the template properties and also confirms the nanotube association mechanism. Linear polymer composites were formed using this SMA template: pyrrole was polymerized, silver nitrate was reduced to silver and silver cyanide nanowires were grown.

A simple hydrothermal reaction between Ba(NO3)2 and K2SiF6 results in the formation of 1D rod-like BaSiF6. The BaSiF6 rods can act as efficient precursors for production of tubular SiO2 by hydrothermal reaction in alkaline solutions. Powder X-ray diffraction (XRD), X-ray photoelectron spectra (XPS), transmission electron microscopy (TEM), high resolution electron microscopy (HRTEM), and field emission scanning electron microscopy (FESEM) were used to characterize the phase and morphology of the final product. The experiments indicated the amount of NaOH, reaction temperature, and reaction time played important roles in the transformation process. A possible growth mechanism of tubular silica was proposed.

Three-dimensionally ordered macroporous (3DOM) nickel films are fabricated by electro-deposition into the interstitial spaces of polystyrene (PS) template formed by PS latex spheres self-assembled on nickel alloy substrates. Yttria stabilized zirconia (YSZ) precursor prepared by the sol–gel method is infiltrated in the voids of the 3DOM nickel films. After heat treatment, a novel structure of 3DOM nickel films with YSZ filled in the hollow regions (3DOM Ni/YSZ composite) has been obtained. Structure and surface morphology of the specimens were studied by X-ray diffractometry (XRD) and scanning electronic microscopy (SEM), respectively. The thermal analysis (TG-DTA) was carried out to study the thermal decomposition process of YSZ gel. When the compound specimen is calcined at 600 °C or higher temperature, the YSZ with cubic structure phase can be prepared.

A novel series of luminescent mesoporous organic–inorganic hybrid materials has been prepared by linking Eu3+ complexes to the functionalized ordered mesoporous SBA-15 which was synthesis by a co-condensation process of 1,3-diphenyl-1,3-propanepione (DBM) modified by the coupling agent 3-(triethoxysilyl)-propyl isocyanate (TEPIC), tetraethoxysilane (TEOS), Pluronic P123 surfactant as a template. It was demonstrated that the efficient intramolecular energy transfer in the mesoporous material Eu(DBMSi-SBA-15)3phen mainly occurred between the modified DBM (named as DBM-Si) and the central Eu3+ ion. So the Eu(DBMSi-SBA-15)3phen showed characteristic emission of Eu3+ ion under UV irradiation with higher luminescence quantum efficiency. Moreover, the mesoporous hybrid materials exhibited excellent thermal stability as the lanthanide complex was covalently bonded to the mesoporous matrix.

We demonstrate a facile route to decorate the surface of networked single walled carbon nanotubes (SWNTs) with silver nanoparticles (Ag NPs). The method is based on utilization of either spherical poly(styrene-b-4vinylpyridine) (PS-b-P4VP) or cylindrical poly(styrene-b-acrylic acid) (PS-b-PAA) copolymer micelles capable of stabilizing nanotubes in solution and subsequently forming a thin and uniform block copolymer/SWNTs composite film upon spin coating. The selective doping of silver acetate into either P4VP or PAA domains in a thin composite film, followed by thermal treatment, results in the formation of Ag NPs in the cores of micelles. Further heat treatment at 500 °C sufficiently high for degrading both block copolymers allows us to fabricate a thin SWNTs network in which Ag NPs are efficiently deposited on the surface of nanotubes. A sharp surface plasmon absorption band around 400 nm of the networked SWNTs with Ag NPs confirms the presence of Ag NPs with narrow distribution in their size.

Large-scale, well-aligned, and oriented semiconductor ZnSe nanobelt arrays have been achieved via the thermal treatment of belt-like precursor (ZnSe·ethylenediamine), which has been synthesized by a simple template-free solvothermal route. ZnSe nanobelts grow perpendicularly on zinc substrate, with thickness of about 50 nm, widths of several hundreds of nanometers, and lengths of up to several micrometers. The as-obtained products have been characterized by scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray, and photoluminescence spectrometer. The cooperative action of the mixed solvents is responsible for the formation of the morphology of the resulting ZnSe nanobelt arrays. Room-temperature photoluminescence measurement indicates that the as-obtained ZnSe nanobelt arrays have a strong emission peak centered at 578 nm and two weak emission peaks centered at 420 and 433 nm. The strong emission from the unique well-aligned ZnSe nanostructures reveals their potential as building blocks for optoelectronics devices.

Hollow CaCO3 particles were synthesized by passing CO2/N2 bubbles into a CaCl2 solution. The formation of such hollow particles was investigated via the nucleation mechanism of calcium carbonate. It was found that homogeneous and heterogeneous nucleation both occurred via a three phase gas−liquid−solid reaction. However, only the latter played a role in the formation of the described hollow particles. Nuclei were initially formed at the bubble surface and subsequently aggregated together to form the initial shell. Growth of the initial shell structure proceeded along the bubble surface by the subsequent aggregation of nuclei. Concurrently it was found that the combination of reaction ions, Ca2+ and CO32−, adsorbed on the outer surface of the growing shell resulted in the increase of shell thickness in a direction perpendicular to the bubble template surface. Both aggregation of nuclei and crystal growth contributed to the formation of the shell structure, with distinguishable inner and outer layers presen...

CdS nanoparticles of 4.5 nm diameter were synthesized in poly(2-vinylpyridine) micellar cores which were obtained by solvating a polystyrene-block-poly(2-vinylpyridine) block copolymer in polystyrene-selective toluene. Then, a C 60 -toluene solution was dispersed into the CdS micelle solution with stirring. This led to the well-defined organization of two different nanoparticles; specifically: a CdS NP decorated by several/dozens of C 60 molecules, because C 60 molecules were strongly coordinated with pyridine molecules in the micellar cores by charge-transfer complexation C δ― 60 ―P2VP δ+ . A harmoniously organized CdS/ C 60 micellar structure was clearly verified by transmission electron microscopy. Fluorescent quenching of CdS nanoparticles, which was strongly affected by neighboring C 60 molecules, was observed.

Zeolite/glass composite materials with hierarchical trimodal pore size distributions have been successfully prepared and subsequently characterized. Starting from glass monoliths having meso- and macropores, additional microporosity was introduced while allowing the growth of zeolite crystals via partial recrystallization of the glass support into ZSM-5 zeolite phase. Structured zeolitic catalytic materials were produced using a combination of supramolecular templating methods to produce the glass support, followed by conventional self-assembly of template cations and silica species. Zeolite crystals are therefore in intimate contact with the glass support, featuring micropores in addition to the mesopores. Hence, these zeolite/glass composites exhibit enhanced diffusional properties in comparison with purely microporous zeolite materials. These enhanced mass transport properties allowed improvement of the selectivity toward light olefins in the important n-hexane cracking reaction.

Novel one-dimensional europium benzene-1,3,5-tricarboxylate compressed nanorods have been synthesized on a large scale through direct precipitation in solution phase under moderate conditions without the assistance of any surfactant, catalyst, or template. The obtained nanorods have widths of about 50−100 nm, thicknesses of 10−20 nm, and lengths ranging from a few hundred nanometers to several micrometers. X-ray powder diffraction, elemental analysis, Fourier transform infrared studies, and thermogravimetric and differential thermal analysis show that the nanorods have the structural formula of Eu(1,3,5-BTC)·6H2O. Upon UV excitation, these nanorods exhibit a highly efficient luminescence, which comes from the Eu3+ ions. Moreover, Eu2O3 nanorods could also be obtained via a thermal decomposition method using the corresponding complex as a precursor. This synthetic route is promising for the preparation of other one-dimensional crystalline nanomaterials because of its simplicity and the low cost of the star...

High temperature ceramics with porosity on multiple length scales offer great promise in high temperature catalytic applications for their high surface area and low flow resistance in combination with thermal and chemical stability. We have developed a bottom-up approach to functional, porous, high-temperature ceramics structured on eight distinct length scales integrating functional Pt nanoparticles from the near-atomic to the macroscopic level. Structuring is achieved through a combination of micromolding and multicomponent colloidal self-assembly. The resulting template is filled with a solution containing a solvent, a block copolymer, a ceramic precursor, and a nanoparticle catalyst precursor as well as a radical initiator. Heat treatment results in three-dimensionally interconnected, high-temperature ceramic materials functionalized with well-dispersed 1-2 nm Pt catalyst nanoparticles and very high porosity.

The reaction of zinc(II)bromide and zinc(II)-, cadmium(II)-, and mercury(II)iodide with 2,2-dimethylaziridine (az) yields tetrahedral mononuclear complexes of the type (az)2MX2 (M = Zn, X = Br, I; M = Hg, X = I). The reaction of CdI2, however, with az yields the formal dimerized ligand N-(2-aminoisobutyl)-2,2-dimethylaziridine (aiaz) forming the ionic complex [(aiaz)2CdI]2[CdI4]. This dimerization of two az ligands into the new bidentate aiaz ligand occurs in the coordination sphere of the metal via a metal-mediated template reaction. This may be favored by the formation of a five-membered N,N′-chelating ring. While the zinc(II) and mercury(II) complexes show tetrahedral geometries of the type (az)2MX2, the cadmium aiaz complex consists of two mono cationic trigonal bipyramidal coordinated cadmium(II) centers and one tetrahedral [CdI4]2− dianion. †This article is dedicated to Prof. em. Dr H.C. Wolfgang Steglich on the occasion of his 75th birthday.