Materials Literature
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The structures of hydrogen silsesquioxane based porous low dielectric constant (low- k ) films (XLK) prepared with varying process conditions are characterized using a combination of high-energy ion scattering, X-ray reflectivity, and small-angle neutron scattering. We measure the film thickness, average mass density,…
Abstract The synthesis of second‐generation (G‐2) dendritic polymers of isoprene (I) and styrene (S) was achieved with anionic polymerization high‐vacuum techniques and by performing the following steps: (1) selective reaction of a living chain with the chlorosilane group of 4‐(chlorodimethylsilyl)styrene (a dual‐func…
We report high-resolution specific-heat measurements on the quasi-two-dimensional organic superconductor $\ensuremath{\kappa}\ensuremath{-}(\mathrm{BEDT}\ensuremath{-}\mathrm{TTF}{)}_{2}\mathrm{Cu}(\mathrm{NCS}{)}_{2},$ performed by using a sensitive ac-modulation technique. The main observations are (i) a discontinui…
Highly ( S )-enriched substituted poly(ε-caprolactone)s were synthesized from 4-methyl-ε-caprolactone (4-MeCL) and 4-ethyl-ε-caprolactone (4-EtCL) by lipase Novozym-435 (from Candida antarctica ) catalyzed ring-opening polymerizations. The polymerizations were performed in bulk, thus eliminating the need for solvents…
We report the control of molecular orientation in solid films through self-organization and induced-orientation processes. We synthesized water-soluble cationic 3,4,9,10-perylene diimide ( 1 ) and studied its self-organization in aqueous solution. By UV−vis spectroscopy, H-aggregates of 1 were observed forming in solu…
The synthesis of highly ordered cubic mesoporous silica MCM-48 with tunable pore sizes in the range 1.6−3.8 nm is reported. Pore size control has been achieved by using (mixtures of) gemini surfactants, [CH 3 (CH 2 ) n NMe 2 (CH 2 ) m NMe 2 (CH 2 ) n CH 3 ] 2+ 2Br -, of different average chain length ( m = 12 and n =…
Diamond is a wide-band-gap material with large donor and acceptor ionization energies. In principle, at room temperature and below, the Fermi energy is pinned close to the donor or acceptor level, depending on which is present in the higher concentration. In semiconductors with shallow donors and acceptors the equilib…
Abstract Conductive polymer composites possessing a low percolation‐threshold concentration as a result of double percolation of a conductive filler and its host phase in an immiscible polymer blend afford a desirable alternative to conventional composites. In this work, blends of high‐density polyethylene (HDPE) and…
We report the formation of novel self-assembled ultrathin (ca. 20 nm) films comprising in-plane arrays of nanoscale surface cavities. The original micellar thin films, formed by casting kinetically stable reverse micelles from a solution of a styrene (PS)−acrylic acid (PAA) diblock copolymer in toluene onto silicon ni…
We have measured the differential conductance of individual multiwall carbon nanotubes. Coulomb blockade and energy level quantization are observed. The electron levels are nearly fourfold degenerate (including spin) and their evolution in magnetic field (Zeeman splitting) agrees with a g factor of 2. In zero magnetic…
We present a systematic analysis of the effect of radial deformation on the atomic and electronic structure of zigzag and armchair single wall carbon nanotubes using the first-principle plane wave method. The nanotubes were deformed by applying a radial strain, which distorts the circular cross section to an elliptica…
We have performed first principles electronic structure calculations to investigate the structural and magnetic properties of Fe/ZnSe(001) interfaces. Calculations involving full geometry optimizations have been carried out for a broad range of thickness of Fe layers(0.5 monolayer to 10 monolayers) on top of a ZnSe(00…
We investigate the flow of granular material in a rotating cylinder numerically using molecular dynamics in two dimensions. The particles are described by a new model which allows to simulate geometrically complicated shaped grains. The results of the simulation agree significantly better with experiments than the res…
We present magnetization measurements on \ensuremath{\sim}3-nm $({\mathrm{Fe}}_{0.26}{\mathrm{Ni}}_{0.74}{)}_{50}{\mathrm{B}}_{50}$ ferromagnetic amorphous nanoparticles. Our results show evidence of the surface contribution to the magnetic properties in the $M(H),$ $M(T)$ and relaxation measurements. We observe a lar…
In the present work, the bulk degradation of SiC in hadron (pion and proton) fields, in the energy range between 100 MeV and 10 GeV, is characterised theoretically by means of the concentration of primary defects per unit fluence. The results are compared to the similar ones corresponding to diamond, silicon and GaAs.
We propose a model for collisions between particles of a granular material and calculate the restitution coefficients for the normal and tangential motion as functions of the impact velocity from considerations of dissipative viscoelastic collisions. Existing models of impact with dissipation as well as the classical…
Polyelectrolyte adsorption onto an oppositely charged interface is determined by electrostatic and secondary interactions. Since polyelectrolytes precipitate at elevated temperatures, the secondary interactions are presumably temperature dependent. This idea is tested for poly(allylamine) hydrochloride/polystyrene sul…
We propose a new model for the description of complex granular particles and their interaction in molecular dynamics simulations of granular material in two dimensions. The grains are composed of triangles which are connected by deformable beams. Particles are allowed to be convex or concave. We present first results…
We investigate curvature effects on geometric parameters, energetics, and electronic structure of zigzag nanotubes with fully optimized geometries from first-principle calculations. The calculated curvature energies, which are inversely proportional to the square of radius, are in good agreement with the classical ela…
The recently introduced new class of contrast agents (CAs) based on chemical exchange saturation transfer (CEST) may have a huge potential for the development of novel applications in the field of MRI. In this work we explored the CEST properties of a series of Lanthanide(III) complexes (Ln = Eu, Dy, Ho, Er, Tm, Yb) w…