Self-organized nanostructures of poly(4-vinylpyridine), polyaniline and polyamides due to metal complexation

Comb-shaped supramolecules are constructed using flexible polymers and semi-rigid conjugated undoped or doped conjugated polymers upon complexing Zinc dodecyl benzene sulphonate, Zn(DBS)₂. Selforganized nanostructures are formed in the bulk due to competing attractive interactions (coordination or water mediated hydrogen bonding) and repulsive polar/nonpolar interactions, showing characteristic long periods of ca. 30 Å.     

Benzenedisulfonic Acid as an ALD/MLD Building Block for Crystalline Metal-Organic Thin Films**

Two new atomic/molecular layer deposition processes for depositing crystalline metal-organic thin films, built from 1,4-benzenedisulfonate (BDS) as the organic linker and Cu or Li as the metal node, are reported. The processes yield in-situ crystalline but hydrated Cu-BDS and Li-BDS films; in the former case, the crystal structure is of a previously known metal-organic-framework-like structure, while in the latter case not known from previous studies. Both hydrated materials can be readily dried to obtain the crystalline unhydrated phases. The stability and the ionic conductivity of the unhydrated Li-BDS films were characterized to assess their applicability as a thin film solid polymer Li-ion conductor.     

Division point measures resulting from triangle subdivisions

When dividing a 1- or 2-dimensional region according to a specified scheme, division points are continually created as the process continues. A measure results from assigning weights to each of these points. In the 1-dimensional setting, results concerning the distribution of division points are well known, and suggest how to study analogous processes in two dimensions. We explore two different division schemes on a triangular region and three different measures based on each subdivision, finding the limiting measures in each case.     

Regularity of fractional maximal functions through Fourier multipliers

We prove endpoint bounds for derivatives of fractional maximal functions with either smooth convolution kernel or lacunary set of radii in dimensions $n\ge 2$. We also show that the spherical fractional maximal function maps $L^p$ into a first order Sobolev space in dimensions $n\ge 5$.     

Lipschitz Linearization of the Maximal Hyperbolic Cross Multiplier

Journal of Fourier Analysis and Applications - We study the linearized maximal operator associated with dilates of the hyperbolic cross multiplier in dimension two. Assuming a Lipschitz condition...     

Melt‐compounded nanocomposites of titanium dioxide atomic‐layer‐deposition‐coated polyamide and polystyrene powders

Polyamide and polystyrene particles were coated with titanium dioxide films by atomic layer deposition (ALD) and then melt‐compounded to form polymer nanocomposites. The rheological properties of the ALD‐created nanocomposite materials were characterized with a melt flow indexer, a melt flow spiral mould, and a rotational rheometer. The results suggest that the melt flow properties of polyamide nanocomposites were markedly better than those of pure polyamide and polystyrene nanocomposites. Such behavior was shown to originate in an uncontrollable decrease in the polyamide molecular weight, likely affected by a high thin‐film impurity content, as shown in gel permeation chromatography (GPC) and scanning electron microscope (SEM) equipped with an energy‐dispersive spectrometer. Transmission electron microscope image showed that a thin film grew on both studied polymer particles, and that subsequent melt‐compounding was successful, producing well dispersed ribbon‐like titanium dioxide with the titanium dioxide filler content ranging from 0.06 to 1.12 wt%. Even though we used nanofillers with a high aspect ratio, they had only a minor effect on the tensile and flexural properties of the polystyrene nanocomposites. The mechanical behavior of polyamide nanocomposites was more complex because of the molecular weight degradation. Our approach here to form polymeric nanocomposites is one way to tailor ceramic nanofillers and form homogenous polymer nanocomposites with minimal work‐related risks in handling powder form nanofillers. However, further research is needed to gauge the commercial potential of ALD‐created nanocomposite materials. Copyright © 2011 John Wiley & Sons, Ltd.     

Characteristics of multivariate distributions and the invariant coordinate system

We consider a semiparametric multivariate location–scatter model where the standardized random vector of the model is fixed using simultaneously two location vectors and two scatter matrices. The approach using location and scatter functionals based on the first four moments serves as our main example. The four functionals yield in a natural way the corresponding skewness, kurtosis and unmixing matrix functionals. Affine transformation based on the unmixing matrix transforms the variable to an invariant coordinate system. The limiting properties of the skewness, kurtosis, and unmixing matrix estimates are derived under general conditions. We discuss related statistical inference problems, the role of the sample statistics in testing for normality and ellipticity, and connections to invariant coordinate selection and independent component analysis.     

Electron ionization mass spectra and tautomerism of 2-phenacylpyridines

The electron ionization mass spectra of 2-phenacylpyridine (ketimine form) and its 13 derivatives substituted in the benzene ring (1an: a R = H, b 3-Me, c 4-Me, d 4-NH(2), e 3-F, f 4-F, g 4-OMe, h 4-Cl,i 4-N(CH(3))(2),j 4-NO(2), k 4-CF(3), l 4-N(CH(2))(4), m 4- Br, n 3-Br) were recorded at 70 eV to determine the fragmentation routes and to screen the presence of their enolimine tautomers, (Z-)-2-(2-hydroxy-2-phenylvinyl)pyridines in the gas phase. The total ion currents (TIC) of the ions [MH](+), [MHCO](+), 2-PyCH(2)O(+), and RC(6)H(4)CO(+) (= ArCO(+) ) showed a fair or good correlation with the Hammett s constants (R = 0.859, 0.876, 0.912, and 0.926, respectively). The relative abundances (RA) of both the [MCO](+.) and the [MHCO](+) ion increased with the decreasing electron donating ability of the substituents and also correlated relatively well with the Hammett constants (R = 0.834 and 0.907, respectively). These observations, in comparison to the NMR results, show that the relative contribution of the ketimine tautomer also increases in the gas phase with the increasing electron donating ability of the phenyl substituent, i.e. the TIC of the ArCO(+) ion decreases whereas that of [MH](+) ion increases.