Materials Literature
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Block copolymer micelles have shown high potential as hydrophobic drug carriers. The loading efficiency, partition coefficient, and release profile all play critical roles in micellar drug delivery. As part of a series of studies on these polycaprolactone- block -poly(ethylene oxide) (PCL - b -PEO) micelles in drug de…
Preparation of carbon nanotube (CNT)/alumina composites by a simple colloidal processing method has been reported in this paper. The surface modification process of carbon nanotubes was characterized by means of zeta potential measurements and TEM microscopy. The addition of only 0.1 wt % carbon nanotubes in the alumi…
We have carried out molecular dynamics simulations of model polymer–nanoparticle composites (PNCs) consisting of coarse-grained bead-necklace polymer chains and roughly spherical nanoparticles comprised of like beads for the purpose of gaining understanding of the influence of the nanoparticle–polymer interface on the…
Basis sets of atomic orbitals are very efficient for density functional calculations but lack a systematic variational convergence. We present a method to optimize numerical atomic orbitals variationally, using a single parameter to control their range. The efficiency of the basis generation scheme is tested and compa…
We report on the doping dependence of the order of the ferromagnetic metal to paramagnetic insulator phase transition in ${\mathrm{L}\mathrm{a}}_{1\ensuremath{-}x}{\mathrm{C}\mathrm{a}}_{x}{\mathrm{M}\mathrm{n}\mathrm{O}}_{3}$. At $x=0.33$, magnetization and specific heat data show a first order transition, with an en…
A technique to investigate the adhesion of carbon nanotubes to a polymer matrix is described. Carbon nanotubes bridging across holes in an epoxy matrix have been drawn out using the tip of a scanning probe microscope while recording the forces involved. A full force-displacement trace could be recorded and correlated…
Filled elastomers exhibit a complex dependence of their viscoelastic modulus as a function of both temperature and frequency. Otherwise, recent observations on thin polymer films have shown that their glass transition temperature depends on their thickness. On the basis of these recent results and on a recent model, w…
One-dimensional silicon-carbon nanotubes and nanowires of various shapes and structures were synthesized via the reaction of silicon (produced by disproportionation reaction of SiO) with multiwalled carbon nanotubes (as templates) at different temperatures. A new type of multiwalled silicon carbide nanotube (SiCNT), w…
We have studied the enhancement of luminescence of (CdSe)ZnS core−shell quantum dots on gold colloids as a function of semiconductor nanocrystal−metal nanoparticle distance. Using a layer-by-layer polyelectrolyte deposition technique to insert well-defined spacer layers between gold colloids and quantum dots, a distan…
On-board diagnosis (OBD) aims at detecting malfunctions of emission-related components of road vehicles. It is required by legislation in United States and the European Union, as it is considered to be beneficial for the reduction of vehicle-related air pollution. On-board diagnosis of the catalytic converter is a cha…
Yil: 2002Cilt: 26Sayi: 6ISSN: 1300-0527 / 1303-6130Sayfa Araligi: 925 - 937Metin Dili:Ingilizce
Abstract Radiation‐induced grafting of acrylic acid (AAc) onto polyethylene (PE) film was investigated. The grafted films rapidly adsorbed Eu, Gd, Tb, and Dy ions at high efficiency. The carboxylic acid groups on the AAc‐grafted PE film acted as a chelating site for the selected lanthanide ions. Complex formation of l…
Two cationic phthalocyanines (Pc), a tetravalent Alcian Blue pyridine variant (ABpy4+) and a monovalent iron(III) phthalocyanine (FePc+), were intercalated into two layered titanates derived from Na2Ti3O7 and CsxTi2 − x/4□x/4O4 (□ = vacancy, x = 0.7) by using the corresponding propylammonium titanates as the intermedi…
The silicon $2p$ photoelectron spectra for $\mathrm{S}\mathrm{i}{\mathrm{H}}_{\mathrm{4}}$, $\mathrm{S}\mathrm{i}{\mathrm{F}}_{\mathrm{4}}$, and $\mathrm{S}\mathrm{i}\mathrm{C}{\mathrm{l}}_{\mathrm{4}}$ have been analyzed to give the natural linewidths of the Si $2p$ hole states, which reflect the Auger decay rates of…
Sorption of two dinitrophenolic herbicides, 4,6-dinitro-o-cresol (DNOC) and 4,6-dinitro-2-sec-butylphenol (DINOSEB) to smectite was studied using FTIR, HPLC, and quantum chemical methods. The high affinity of DNOC and DINOSEB for smectite surfaces was attributed to site-specific interactions with exchangeable cations…
Abstract The textural and electrooptical behavior of a nematic liquid crystal (LC) dispersed in a flexible and rigid polyester was studied. The dispersion of LC in the polymer matrix and light transmission through the polymer‐dispersed liquid crystal (PDLC) is governed by the nature of the polymer, its molecular weigh…
Abstract Poly(ethylene oxide) (PEO) star polymers were prepared by anionic polymerization of methacryloyl chloride and glyceryl trimethacrylate with sec ‐butyllithium in cyclohexane. The ensuing polymers were grafted with poly(ethylene glycol) of molecular weight 400. The final product was washed with methylene chlori…
We have extended the modified formalism of Sheng, Xing, and Wang [J. Phys.: Condens. Matter 11 L299 (1999)] to allow the calculation of the conductivity of a thin metallic film bounded by a rough fractal surface. We utilized the so-called k-correlation model proposed by Palasantzas and Barnas [Phys. Rev. B 48, 14 472…
Dinitrogen (N 2 ) adsorption on overexchanged Cu-ZSM-5 (Si/Al = 25, 104% ion exchange from copper acetate) was studied at 302 K by diffuse reflectance infrared spectroscopy (DRIFTS), N 2 -adsorption isotherms, and temperature-programmed N 2 desorption (TPD). We found that Cu-ZSM-5 adsorbs N 2 at least in two different…
Abstract Sodium polyacrylate superabsorbent polymers were prepared in particle forms by the inverse suspension technique. The surfactant concentration effect on the polymer particle size was analyzed with molecular sieves and an optical microscope. Water absorption and desorption characteristics were analyzed by the g…