Materials Literature
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Phosphate films with thicknesses on the order of the original native metal oxide have been formed on oxide-free aluminum and iron surfaces by electrochemical treatment in 5M phosphoric acid. Electrochemistry was performed under inert atmosphere in a previously described anaerobic cell. The metal phosphate films formed…
Electron energy loss spectroscopy is a well adapted tool for the investigation of the valence excitations of individual nanometer-size particles. The interpretation of the loss spectra of such small particles, however, relies in most cases on a quantitative comparison with simulated excitation probabilities. Here we p…
Abstract A general method for the controlled synthesis of polylactide in solution and from solid supports is presented. The evaluation of stannous(II) trifluoromethane sulfonate [Sn(OTf) 2 ] and scandium(III) trifluoromethane sulfonate [Sc(OTf) 3 ] as catalysts for the ring‐opening polymerization (ROP) of L ‐, D ‐, an…
Sol−gel processing of new materials for second-order nonlinear optics promises to be a simple and highly versatile synthetic route among those that have been evaluated to achieve large and stable second-harmonic generation. Introduction to various types of organic chromophore−inorganic matrix hybrid materials that hav…
The behavior as a function of temperature of very thin films (10 to 200 nm) of pentylcyanobiphenyl on silicon substrates is reported. In the vicinity of the nematic-isotropic transition we observe a coexistence of two regions of different thicknesses: thick regions are in the nematic state while thin ones are in the i…
The effects of a compatibilizer, poly(propylene-ethylene acrylic acid) (PPEAA) and a silane coupling agent, 3-aminopropyl-triethoxy silane (3-APE), on properties of white rice husk ash (WRHA) filled polypropylene (PP)/natural rubber (NR) blends were investigated. The incorporation of WRHA into PP/NR blends improved te…
Mesoporous silica was synthesized as a support for the removal of copper ions in aqueous solutions. The Sol-gel method in conjunction with neutral surfactants was used. The remaining surfactants were removed by either the Soxhlet or microwave extraction method. Both extractions resulted in the same pore structure of t…
The infrared spectra of phenol and phenol-OD are thoroughly reinvestigated, to resolve the contradictory assignment of some vibrations. The harmonic frequencies, integrated IR intensities, and potential energy distribution (PED) have been calculated by the B3LYP method with the 6-311++G(df,pd) basis set. The Fourier t…
The effects of carbon black and pyrogeneous silica fillers on the interfacial properties of a homopolymer [polybutadiene, (PB)] and a terpolymer [brominated poly(isobutylene- co - p -methylstyrene), (BIMS)] are reported. Neutron reflectivity (NR) was used to study the interfacial structure. The results are complemente…
Using the variational density-functional perturbation theory, we investigate the dynamical and dielectric properties of tetragonal zirconia $(t\ensuremath{-}{\mathrm{ZrO}}_{2}).$ We obtain the phonon frequencies at the center of the Brillouin zone, the Born effective charge tensors, and the dielectric permittivity ten…
A synthetic fluorohectorite clay in which the exchange cations have been replaced by hexadecyltrimethylammonium ions, abbreviated C 16 FH, has been shown to readily intercalate linear poly(dimethylsiloxane) (PDMS) molecules containing terminal hydroxyl groups. The extent of gallery swelling increased with increasing P…
As part of our continuing study of the solid-state morphology of poly(urethane urea) segmented block copolymers, we focus in the current paper on the use of atomic force microscopy to visualize the structure of phase-separated microdomains. Free surface and bulk images were obtained from two series of PUU films, for c…
We present an accurate, first-principles study of the electronic structure and absorption spectrum of bulk copper within Density Functional Theory in the Local Density Approximation (DFT-LDA), including the study of intraband transitions. We construct norm-conserving pseudopotentials (PPs) including the 3d shell (and…
The electrochemically induced volume change in conjugated polymers is of interest for actuator applications. Important parameters include the magnitude and speed of the volume change and how volume correlates with potential and current. In this paper, atomic force microscopy was used to examine the expansion and contr…
The surface modification of aqueous silver colloidal particles with the amino acid cysteine and the cross-linking of the colloidal particles in solution is described. Capping of the silver particles with cysteine is accomplished by a thiolate bond between the amino acid and the nanoparticle surface. The silver colloid…
Atom transfer radical polymerization (ATRP) was applied to the synthesis of amphiphilic cylindrical polymer brushes by using the “grafting from” technique. The procedure included the following steps: (1) ATRP of 2-hydroxyethyl methacrylate (HEMA) gave well-defined poly(HEMA), (2) subsequent esterification of the penda…
Abstract Particle‐dispersed melting is a complex but important melting mechanism in the corotating twin‐screw extruder. In this study, the complex multi‐particle‐dispersed system was simplified into a single‐particle melting model. The finite‐difference method was introduced to solve this problem. The simulation resul…
Abstract The diffusion, solubility, and permeability behavior of oxygen and carbon dioxide were studied in amorphous and semicrystalline syndiotactic polystyrene (s‐PS). The crystallinity was induced in s‐PS by crystallization from the melt and cold crystallization. Crystalline s‐PS exhibited very different gas permea…
Abstract Small‐angle X‐ray scattering (SAXS) gives information on lamellar stacks in semicrystalline polymers. SAXS experiments have been used to follow the melting transition that occurs over a temperature range of 10 °C or more. One common feature is the increase in the average period by 50–100% during the melting p…
PURPOSE: To investigate the interpolymer complexation between Carbopol 934P (CP) and various grades of polyvinylpyrrolidone (PVP) (K90, K32, C15, and VA/S-630). METHODS: Amount of fresh and dried CP-PVP complexes, water retaining capacity, apparent density, pH, conductivity, FTIR, swelling and adhesion strength were s…