Search

Bismuth vanadate (BiVO(sub 4)) nanosheets were synthesized hydrothermally in the presence of a morphology directing agent sodium dodecyl benzene sulfonate (SDBS) and were studied with the help of modern techniques of spectroscopy and electron microscopy. The BiVO(sub 4) nanosheets showed a monoclinic structure with a preferred surface orientation, outstanding spectral selectivity, improved color properties and higher photcatalytic activities.

The interactions of cyanoacetylene and diacetylene with a Si(111)-7 x 7 surface is studied as model systems to mechanically understand the chemical binding of unsaturated organic molecules to diradical-like silicon dangling bonds. Results show that cyanoacetylene mainly binds to the surface through a diradical reaction involving both cyano and C(triple bond)C groups.

Size-dependent surface binding forms of the carboxylic group on the surface of TIO2 nanoparticles are investigated by a surface binding transient probe molecule all-trans-retinoic acid. Different TiO2 nanoparticles of varying size are prepared and their physical properties are examined by X-ray diffraction, transmission electron microscopy and selected-area electron diffraction.

Multilayer films containing gold nanoparticles, stabilized with a carboxylic acid terminated thiol and the polyelectrolyte PDDA are synthesized on APTES-functionalized silicon substrates. It is evident from the Kelvin probe measurements that the sign of the surface charge oscillates, as expected if layer formation is being driven by electrostatic interactions.

Studies done on the fabrication and supramolecular chirality of complex multilayer films of tetrakis(4-sulfonato-phenyl)-porphine (TPPS) and long-chain enantiomers of tryptophan derivatives (D-Trp or L-Trp) are reported. Complex multilayer films of TPPD and chiral Trp amphiphiles can be formed by in situ or ex situ adsorption and it was observed that TPPS could form J aggregates and show chirality in both types of multilayer films.

The characteristics of binary monolayers are discussed in relation to wettabilty, electrochemical and reflection absorption spectroscopic measurements.

Some novel morphology of calcium carbonate (CaC[O.sub.3]) is precipitated in an ethanol-water binary solvent (EWBS) with a Ca[Cl.sub.2]/[Na.sub.2]C[O.sub.3] reaction system. It is shown that EWBS has a divisive effect on [Ca.sup.2+] and C[O.sub.3.sup.2-] and the local inhomogeneity of EWBS is increased by adding some [Na.sub.2]C[O.sub.3] into it.

Molecular dynamics simulations are employed to study the various structured water and water-polymer interactions taking place in the hydrogels of molecularly imprinted polymers. The structure of water is shown to become weaker with an increase in the mesh size of the polymer.

The article presented a newly developed method, which is used for the label-free detection of sequence-specific (ss) DNA with multiwalled carbon nanotubes (MWCNTs) and their light scattering signals. The ssDNA are shown to be capable of preventing MWCNTs from coagulation in the electrolyte solution.

A kinetic model is used for understanding the behavior of crystal dissolution to aluminosilicate dissolution kinetics. The stochastic model has integrated all microscopic information at the atomic scale and has explored the reasons for the kinetic results in experimental studies, thus improving the understanding of the aluminosilicate dissolution.

Molecular dynamics simulations are used to investigate the diffusion behavior of a model drug in different ratios of poly(lactic acid-co-ethylene glycol) (PLA-PEG). The comparison of the diffusion behavior of small gas molecules in polymer matrix has led to the development of a different mechanism for the drug molecules.

Computer tomography for materials (mCT) is used to study the adsorption sites inside metal-organic frameworks (MOFs) at any positions and any view angles. The analysis has shown that the introduction of some stronger electronegative atoms to the frameworks might be a feasible way for improving the hydrogen storing capacity.

A study demonstrates that 3-D micromachining by indirect electrochemical etching of n-GaAs and p-Si can be accomplished using the confined etchant layer technique (CELT) with appropriate etching solutions. Results indicate that the success of this process depends mainly on the concentration of l-cystine to [Br.sup.-] in the etching solution.

The monodisperse silver nanoparticles were synthesized by one-step reduction of silver ions in the alkaline subphase beneath vitamin E (VE) Langmuir monolayers and their structure was investigated. The results suggested that excellent quality V[E.sub.q]/silver nanocomposite LB films might be formed on different substrates without significant variation in the nanoparticle density.

The formation and evolution of the solid electrolyte interphase (SEI) film on the surface of natural graphite spheres in the electrolyte of 1M LiPF6 in ethylene carbonate (EC) and ethylene dimethyl carbonate (DMC) with focused ion beam (FIB) technology is investigated. The results enrich the knowledge of the SEI film and may be helpful for the design and upgrading of high-performance lithium ion batteries.

The supramolecular assemblies between a series of novel gemini amphiphiles (BisIm17Cn) and TPPS (tetrakis-(4-sulfornatophenyl)porphine) at the air/water interface are investigated. The J-aggregation of TPPS into gemini amphiphile monolayers and the chirality of the transferred nultilayer films are characterized by the pi-A isotherms, CD spectra, UV-vis spectroscopy and atomic force microscopy (AFM) measurements.

A series of gold nanoparticles stabilized by the absorption of heterocyclic mercaptan derivatives, including 2-mercaptopyridine (2MPy), 2-mercaptopyrimidine (2MPm) and 4-mercaptopyridine (4MPy), are synthesized and characterized by Transmission Electron Microscopy (TEM), Fourier Transform Infrared Spectroscopy (FTIR), UV-visible Spectroscopy (UV-vis), and X-ray Photoelectron Spectroscopy (XPS). The absorption of 2MPy molecules led to the most stable and uniform nanoparticles, and 4MPy- coated nanoparticles showed tendency to form 3D aggregates.

Complex monolayer formation between three amphiplies: cetyltrimethylammonium bromide (CTAB), octadecylamine (ODA), dioctadecyldimethylammonium bromide (DOAB), and tetrakis(4-sulfonatophenyl)-porphine (TPPS) at the air/water interface are investigated using a Langmuir-Schaefer (LS) method. It was found that the TPPS could form complex monolayers with the amphiphiles at the air/water interface through the electrostatic interaction at pH = 3.1.

Controlling the process of crystal growth is of importance to the biomineralization and materials science. In this work, some novel morphology of calcium carbonate (CaCO 3) was precipitated in an ethanol−water binary solvent (EWBS) with a CaCl 2/Na 2CO 3reaction system. For the solutions of CaCl 2/Na 2CO 3in EWBS, the alcoholization and hydration of Ca 2+and CO 32−were discussed from the radial distribution functions by molecular dynamics simulations, and the number density profiles of water molecules around and ∼15 Å away from CO 32−were employed to reveal the distribution of water molecules. It is found that EWBS has a divisive effect on Ca 2+and CO 32−, and the local inhomogeneity of EWBS would be enhanced by adding some Na 2CO 3into it. This inhomogeneity results in an aqueous two-phase system as xEgoes up to 0.7. In addition, the novel morphology of CaCO 3under different molar ratios of Ca 2+/CO 32−and in different mixed solvents were confirmed by XRD and SEM, and the relationships between the morphology of CaCO 3and the structural properties of mixed solvents were further explored. [ABSTRACT FROM AUTHOR]

Carbon encapsulated magnetic (metal) nanoparticles (CEMNPs) have wide applications in biomedicine and the magnetic recording industry. However, synthesis of such particles with a high coercive force and good ferromagnetism is still a great challenge. The present study reports a new method for the continuous production of CEMNPs of high purity. This involves the spray pyrolysis of a mixture of iron pentacarbonyl and ethanol at 500−900 °C. Results show that the Fe (or Fe3C) particles synthesized at 700 and 900 °C were well encapsulated by graphitic layers with rare byproducts such as carbon nanotubes, nanofibers, or bulk amorphous carbon. Those synthesized at 700 °C had a particle size of 30−50 nm, a giant coercive force of 867 Oe, and a good magnetic remanence of 33% at room temperature. The present approach based on spray pyrolysis is advantageous over previous ones in suitability for large-scale production, and the synthesized material has wide applications in many fields. [ABSTRACT FROM AUTHOR]

Bismuth vanadate (BiVO4) nanosheets have been hydrothermally synthesized in the presence of sodium dodecyl benzene sulfonate (SDBS) as a morphology-directing template. The nanosheets were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM) equipped with an X-ray energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), IR spectroscopy, transmission electron microscopy (TEM), and high-resolution TEM (HR-TEM). The BiVO4 nanosheets had a monoclinic structure, were ca. 10−40 nm thick, and showed a preferred (010) surface orientation. The formation mechanism and the effects of reaction temperature and time on the products were investigated. UV−visible diffuse reflection spectra indicated that the BiVO4 nanosheets had outstanding spectral selectivity and improved color properties compared with the corresponding bulk materials. Furthermore, the nanosheets showed good visible photocatalytic activities as determined by degradation of N,N,N‘,N‘-tetraethylated rhodamine (RB) under solar irradiation. [ABSTRACT FROM AUTHOR]