Materials Literature
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Detailed diffuse-reflectance infrared Fourier transform structural analysis of a series of organically modified silicates (ORMOSIL)-entrapped catalysts, varying the molar percentage and the alkyl chain length of the organic group, shows that the important factors affording optimal catalytic performance are two: predom…
A relationship between the chemical composition, structure and luminescent properties of light-emitting SiOxNy(Si) composite layers with Si nanocrystals is demonstrated. Photoluminescence (PL) with a maximum of intensity at 500-600 nm is observed in a narrow region of chemical compositions with relatively small Si exc…
We present an experimental system suitable for producing spherical crystals and for observing the distribution of lattice defects (disclinations and dislocations) on a significant fraction (50%) of the sphere. The introduction of fluorescently labeled particles enables us to determine the location and orientation of g…
Abstract This article provides an overview of some recent developments related to the synthesis and functionalization of monodisperse colloidal spheres, a class of colloidal materials that has found widespread use in applications such as the fabrication of photonic crystals, optical sensing, and drug delivery. Traditi…
Poly(L-lysine)-g-poly(ethylene glycol) (PLL-g-PEG) copolymers with various grafting ratios were adsorbed to niobium pentoxide-coated silicon wafers and characterized before and after protein adsorption using X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). Three pro…
Hexadecyltrimethylammonium bromide (CTAB), which is necessary for the preparation of gold nanorods (NRs), was extracted from a NR solution into a chloroform phase containing phosphatidylcholine (PC). After three extractions, the zeta potential of the NRs remained positive, but its magnitude decreased from +67 +/- 1 to…
MRI detectable and targeted quantum dots were developed. To that aim, quantum dots were coated with paramagnetic and pegylated lipids, which resulted in a relaxivity, r(1), of nearly 2000 mM(-1)s(-1) per quantum dot. The quantum dots were functionalized by covalently linking alphavbeta3-specific RGD peptides, and the…
Nonlinear optical (NLO) materials can be useful for a variety of applications varying from modulation of optical signals facilitated by the electro-optic effect-the effect whereby the refractive index of a material changes in response to an applied electric field-to microfabrication, sensing, imaging, and cancer thera…
The concept, decoupling doping from nucleation and/or growth, allows us to dope nearly all nanocrystals in a given sample which is indicated by complete quenching of the host emission and bright emission from the dopants at characteristic wavelengths tunable in most parts of the visible window using a ZnSe host. In an…
An ab initio study of the surface phonons in high-symmetry points of the Brillouin zone has been performed for the clean MgO(001) surface in the framework of the density functional theory (DFT) using plane waves and a lattice-dynamical treatment with a supercell approach. It is found that a calculation of the surface…
Abstract Allophanes are poorly crystalline and quasi-stable aluminosilicate minerals, the structures of which are sensitive to chemical treatment. In the present study, solid-state 27 Al and 29 Si nuclear magnetic resonance (NMR) spectra of allophane samples were monitored as they went through several purification pro…
The crystal-to-hexagonal columnar mesophase transition in solution-grown single crystals of poly(di- n -propyl siloxane), PDPS, was studied in situ with selected-area electron diffraction and variable-temperature atomic force microscopy. It was observed that, upon the transition, the hexagonal columnar mesophase displ…
Secondary relaxations have been detected in poly(vinyl chloride) (PVC) by measuring the phosphorescence emitted by chromophores present as defects in the polymer chains and in PVC with luminescent probes, pyridine and naphthalene, grafted onto the chain. The measurement of phosphorescence decay with temperature allows…
Abstract Sorption and transformation of 1-naphthol by a K-smectite (K-SWy-2) were studied using batch sorption isotherms, Fourier-transform infrared spectroscopy (FTIR), and X-ray diffraction (XRD). The sorbents included three preparations of the reference smectite clay (SWy-2): (1) whole clay containing naturally occ…
Abstract Sudoite from diagenetic to very low-grade metaclastites of the Betic Cordillera was studied by X-ray diffraction and transmission/analytical electron microscopy. Sudoite formed directly from dickite, the assemblage dickite + sudoite + illite being replaced at increasing metamorphic grade by the assemblage pyr…
The preparation and characterization of two polymorphic phases of AgNd(WO 4 ) 2 are described. The high-temperature phase of AgNd(WO 4 ) 2 is prepared as a polycrystalline powder and as a single crystal. X-ray diffraction analysis indicates that the crystal has at 300 K the tetragonal symmetry of the space group (SG)…
The infrared (IR) chemiluminescence spectra of CO2 were measured during the steady-state CO + O2 reaction over Pt(110) and Pt(111) surfaces. Analysis of the IR emission spectra indicates that the bending vibrational temperature (TVB), as well as the antisymmetric vibrational temperature (TVAS), was higher on Pt(110) t…
A high-resolution calorimetric study has been carried out on nanocolloidal dispersions of aerosils in the liquid crystal $4\text{\ensuremath{-}}n$-pentylphenylthiol-${4}^{\ensuremath{'}}\text{\ensuremath{-}}n$-octyloxybenzoate $(\overline{8}\mathrm{S}5)$ as a function of aerosil concentration and temperature spanning…
The dielectric and electrical conductivity properties of x Pb(Mn 1/3 Sb 2/3 )O 3 –(1− x )Pb(Zr 0.52 Ti 0.48 )O 3 (PMS–PZT) ceramics were studied. X‐ray diffraction indicated that all samples exhibit a single‐phase perovskite structure. Dielectric study revealed that the dielectric relaxor behavior was induced by co‐do…
The emission and excitation spectra of $\mathrm{Ba}{\mathrm{F}}_{2}$ doped with 0.3 and $3.0\phantom{\rule{0.3em}{0ex}}\mathrm{mol}\phantom{\rule{0.2em}{0ex}}%$ ${\mathrm{Pr}}^{3+}$ have been studied using synchrotron radiation in the range from $5\phantom{\rule{0.3em}{0ex}}\text{to}\phantom{\rule{0.3em}{0ex}}30\phant…