Materials Literature
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A new technology to pattern surface charges, either negatively or positively, using a standard photolithography process is introduced. A positively charged poly(allylamine hydrochloride) (PAH) layer is coated onto a negatively charged silicon oxide surface by electrostatic self-assembly (ESA). Combined with photolitho…
Leibler's random phase approximation for block copolymers, modified so as to be applicable to linear multiblock copolymers, has been quantitatively compared to data from three linear ABC/ACB triblock copolymer melts: poly(cyclohexylethylene- b -ethylene- b -ethylethylene) (CEE E )/CE E E, poly(styrene- b -isoprene- b…
A simple approach is reported for the preparation of hollow spheres with a 10−20-nm-thick shell of silicalite-1 nanocrystals. The nanocrystals were produced by the steaming of silicalite-1 nanoprecursors (NPs), collected with the help of surfactant from a clear synthesis solution immediately following the induction pe…
The charge ordering in ${\mathrm{La}}_{1.5}{\mathrm{Sr}}_{0.5}{\mathrm{NiO}}_{4}$ has been studied using the neutron-diffraction technique. An interesting rearrangement of the charge ordering was observed as a function of temperature. With decreasing temperature, a checkerboard-type charge order is formed below ${T}_{…
Three novel ferrocenyl complexes [Zn(4-PFA)(2)(NO(3))(2)](H(2)O) (1), [Hg(2)(OAc)(4)(4-BPFA)(2)](CH(3)OH) (2), and [Cd(2)(OAc)(4)(4-BPFA)(2)] (3) (4-PFA = [(4-pyridylamino)carbonyl]ferrocene, 4-BPFA = 1,1'-bis[(4-pyridylamino)carbonyl]ferrocene) were prepared, and complexes 1 and 2 were structurally characterized by m…
First-principles calculations of the linear and nonlinear optical properties of KH2PO4 (KDP) and CO(NH2)2 are presented. The calculations are an extension of methods we developed earlier and applied to borate crystals. Electronic band structure obtained from a pseudopotential method is input to the calculation. For tw…
Metal nanowire thin films have been obtained by electrodeposition into mesoporous silica thin‐film templates, resulting in nanowire arrays that reflect the pore structure of the template. Removal of silica is achieved via annealing followed by etching to leave mechanically strong freestanding metal nanowire films (see…
The resonant behavior of anatase ${\mathrm{TiO}}_{2}$ (101) and (001) surfaces has been investigated using synchrotron photoemission spectroscopy. The data are compared with earlier photoemission work from rutile ${\mathrm{TiO}}_{2}(110)$ and calculations for bulk anatase in order to elucidate the degree of Ti-O hybri…
An approach to producing a composite material with negative refraction index is demonstrated. It is shown that a photonic structure consisting of two dielectric materials, with positive and negative dielectric permittivities, can support electromagnetic surface waves which exhibit the unusual electromagnetic property…
Abstract Using surfactant‐assisted synthesis, aluminas with hierarchical nanopores are produced. The hierarchical structures are composed of mesopores of 4 nm diameter, and macropores with diameters of about 300 nm. The structures were found to be stable to the thermal removal of the surfactant. Synthesis factors affe…
Through the controlled removal of surfactant from the presynthesized mesolamellar precursor (WO-L) at elevated temperature, tungsten oxide nanowires with diameters ranging from 10 to 50 nm and lengths up to several micrometers were obtained on a large scale. The structure, morphology, and composition of the nanowires…
Large periodic arrays of carbon nanotubes have been grown by plasma-enhanced hot filament chemical vapor deposition on periodic arrays of nickel dots that were prepared by polystyrene nanosphere lithography. A single layer of self-assembled polystyrene spheres was first uniformly deposited on a silicon wafer as a mask…
A new low‐bandgap conjugated polymer is synthesized (see Figure for structure). It is transparent, easily processed, and exhibits electrochromic behavior specific to the near‐infrared region of the spectrum. The absence of electrochromic behavior in the visible range may permit this polymer to be used in near‐infrared…
Densely grafted molecular brushes with AB and ABA “block−graft” architectures, i.e., pODMA- b -p(BPEM- g - n BuA) and pODMA- b -p(BPEM- g - n BuA)- b -pODMA, were synthesized by the “grafting from” approach using atom transfer radical polymerization (ATRP). The backbone macroinitiators were prepared in three steps. Fi…
The molecular deformation of both silkworm (Bombyx mori) and spider dragline (Nephila edulis) silks has been studied using a combination of mechanical deformation and Raman spectroscopy. The stress/strain curves for both kinds of silk showed elastic behavior followed by plastic deformation. It was found that both mate…
The structure of crystallized GeTe films has been studied by x-ray absorption fine structure spectroscopy. We find that in addition to Ge–Te bonds (2.20 and 3.13 Å) ∼10% of Ge–Ge bonds are present. Our results indicate that the crystallized GeTe film consists of GeTe crystallites with 10% Ge vacancies, separated by a…
We conduct a numerical investigation of structural order in the shifted-force Lennard-Jones system by calculating metrics of translational and bond-orientational order along various paths in the phase diagram covering equilibrium solid, liquid, and vapor states. A series of nonequilibrium configurations generated thro…
Abstract This article presents original multi‐scale porous nanocrystalline transition‐metal oxide materials (MO 2 , where M = Ti, Zr, Ce) that have many potential applications. They were prepared through a one step method that combines sol–gel chemistry, multi‐scale templating approaches, aerosol processing, and speci…
We present studies of the photoluminescence (PL), absorption and Raman scattering from poly[2,7-(9,9'-bis(2-ethylhexyl))fluorene] under hydrostatic pressures of 0-100 kbar at room temperature. The well-defined PL and associated vibronics that are observed at atmospheric pressure change dramatically around 20 kbar in t…
We introduce the Korringa-Kohn-Rostocker non-local coherent potential approximation (KKR-NLCPA) for describing the electronic structure of disordered systems. The KKR-NLCPA systematically provides a hierarchy of improvements upon the widely used KKR-CPA approach and includes non-local correlations in the disorder conf…