Materials Literature
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Using stochastic conformal mappings we study the effects of anisotropic perturbations on diffusion limited aggregation (DLA) in two dimensions. The harmonic measure of the growth probability for DLA can be conformally mapped onto a constant measure on a unit circle. Here we map $m$ preferred directions for growth of a…
DW Tomlin, LV Natarajan, VP Tondiglia, RL Sutherland, TJ Bunning; Morphology of Holographic Polymer Dispersed Liquid Crystal Reflection Gratings Written in
We report Raman investigations on stable and metastable phases of cyanoadamantane plastic crystal, which gives an orientational glassy state upon a deep undercooling below 175 K. The isothermal transformation of the metastable quenched plastic phase is systematically analyzed for quenches in the 180−250 K temperature…
Experimental observation of the transformation of cubic symmetry from face-centred cubic (f.c.c.) to body-centred cubic (b.c.c.) for spherical microdomains upon uniaxial stretching of poly(1,3-cyclohexadiene)- block -poly(ethylene-co-but-1-ene)- block -poly(1,3-cyclohexadiene) triblock copolymer, having φ PCHD = 0.293…
We present here the synthesis, characterization, and flash photolysis study of [(F(8)TPP)Fe(II)(CO)(THF)] (1) [F(8)TPP = tetrakis(2,6-difluorophenyl)porphyrinate(2-)]. Complex 1 crystallizes from THF/heptane solvent system as a tris-THF solvate, [(F(8)TPP)Fe(II)(CO)(THF)].3THF (1.3THF), with ferrous ion in the porphyr…
Atomistic and quantum DFT calculations are carried out for models of Ce 0.5 Zr 0.5 O 2 mixed oxide having different cation orderings within a fluorite-type structure. The DFT results are more accurate than those given by the atomistic calculations; these latter exaggerate oxygen sublattice distortions and energy diffe…
M J Campin, J C Barbour, J W Braithwaite, P P Provencio, J G Zhu; Microstructural Studies of the Initial Stages of Copper Sulfide Film Growth: Influence of
Time-resolved small-angle X-ray scattering (TR-SAXS) studies of the structural changes in a block copolymer after a temperature jump are reported. The sample used was a polystyrene- block -poly(ethylene- alt -butylene)- block -polystyrene (SEBS) triblock copolymer, which has a number-average molecular weight of 54000…
Image analysis of semi-crystalline polymer systems in reciprocal space allows quantitative measurement of characteristic periodicities of the material. This paper proposes numerical techniques for the computation of power spectral densities (PSD) and correlation functions, appropriate to this objective, along with a t…
Poly( N -vinylcaprolactam) (PVCL) is a synthetic analogue of biomolecules (enzymes, proteins). It demonstrates a specific hydration and undergoes a coil–globule transition. The PVCL–D 2 O system (PVCL mass M = 10 6 ) has been investigated by small-angle neutron scattering (SANS) at T = 296–316 K to identify the struct…
[reaction: see text] The redox chemistry of pi-extended squaraines is investigated using cyclic voltammetry, in-situ spectroelectrochemistry and quantum chemical calculations. Squaraine 1 is reversibly oxidized to the radical cation and dication whereas reduction shows limited electrochemical but fully chemical revers…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTSuspension Polymerization of l-Lactide in Supercritical Carbon Dioxide in the Presence of a Triblock Copolymer StabilizerDaniel Bratton, Malcolm Brown, and Steven M. HowdleView Author Information School of Chemistry, University of N…
A reconstruction method is presented for the generation of three-dimensional maps of the grain boundaries within powders or polycrystals. The grains are assumed to have a mosaic spread below 1°. They are mapped layer by layer in a non-destructive way by diffraction with hard X-rays. First the diffraction spots are sor…
[Tris(hexamethyldisilyl)amide] yttrium is a catalyst for the controlled ring-opening polymerization of ε-caprolactone when reacted with an excess of alcohol. Up to an alcohol-to-yttrium molar ratio of 50, the chain transfer to the alcohol is quantitative, and the molecular weight of the chains can be predicted from th…
We report a method to prepare hydrophilic poly(dimethylsiloxane) (PDMS) stamps that could transfer patterns of polar molecules homogeneously in soft lithography. In this method, we demonstrated a two-step procedure by using a mixed gas of argon (Ar) and hydrogen (H 2 )-based microwave plasma pretreatment to activate P…
The ground- and excited-state metal-ligand dynamics of nonplanar nickel(II) 2,3,5,7,8,10,12,13,15,17,18,20-dodecaphenylporphyrin (NiDPP) and two fluorinated analogues (NiF(20)DPP and NiF(28)DPP) have been investigated using static and time-resolved absorption spectroscopy in toluene and in ligating media that differ i…
A series of photochemically active, “axial-bonding” type phosphorus(V) porphyrin−azoarene (P−A) conjugates, viz., [(TTP)P V ( - O-AZM) 2 ] +, [(TTP)P V ( - O-AZT) 2 ] +, [(TTP)P V ( - O-AZB) 2 ] +, and [(TTP)P V ( - O-AZN) 2 ] + ( TTP is 5,10,15,20-tetra(4-methylphenyl)porphyrinato dianion and O-AZM, O-AZT, O-AZB, and…
Electrodeposition is a low cost method for WO 3 thin film preparation. The starting dissolved tungsten precursor is a peroxo-compound which can be prepared by an equimolar mixing of sodium tungstate and hydrogen peroxide. The precursor preparation as well as the electrodeposition and precursor solution aging processes…
The effects of the choice of oxygen scattering curves with different ionization levels and of the number of spherical harmonics terms used to correct for preferred orientation are discussed in the case of the Rietveld refinement of MgAl 2 O 4 spinel. Results indicate that Rietveld refinements, and not only single-crys…
Polyelectrolyte-layered films containing α- and β-cyclodextrin were prepared by a layer-by-layer deposition of sulfonated α- or β-cyclodextrin (s-α-CyD or s-β-CyD) and cationic poly(allylamine hydrochloride) (PAH) on a solid surface. The deposition of the films from water solutions (no salt added) afforded thin films…