The direct copolymerization of propene with polar comonomers using metallocene catalysts in solution was investigated. As comonomers, two ether compounds were used in comparison to 10-undecene-1-ol as well-investigated comonomer. The ether comonomers were diethylene glycol mono- 10-undecenyl ether (DEGUE) and octaethylene glycol-10-undecenyl methyl ether (OEGUME). The influence of the different comonomers on the copolymerization behavior was studied. The copolymers were characterized with respect to their comonomer contents, molar masses, and thermal properties. The incorporation rate of DEGUE and OEGUME into the propene copolymers did not exceed 1.6 mol% for DEGUE and 0.31 mol% for OEGUME and was thus considerably lower than in the reference propene copolymerization with 10-undecene-1-ol. An uncompleted shielding of the oxygen atoms of the ether groups by triisobutyl aluminum (TIBA) to the metallocene catalyst is assumed to be responsible for this behavior. The crystallization kinetics in the copolymers with comparable molar masses is mainly influenced by the side chain density per 1000 propene units, n(1000).The incorporation of hydrophilic comonomers into polypropene was expected to alter the surface properties. The slightly lowered water contact angles found on films of copolymers with higher comonomer content indicated the enhanced hydrophilicity of the polypropene copolymer surfaces compared to polypropene (PP). (C) 2007 Elsevier Ltd. All rights reserved.

The crystal structure and the surface of alumina layers on silicon wafers were investigated by means of GIWAXS, WAXS, and AFM. Self-assembled monolayers of omega-substituted long-chain alkylphosphonic acids were deposited on alumina and the layer thickness and homogeneity were determined by ellipsometry revealing a dependency of thickness and homogeneity on the nature of the substituent. During the adsorption process surface etching by the phosphonic acid was observed causing an increase in surface roughness.Furthermore, ex post functional group conversions were carried out yielding surface bound azides and rhodanides.

Novel ways to synthesize poly(vinylamine)/silica hybrid materials rich in free amino moieties using vinylformamide (VFA) as the key monomer are reported. Such materials are accessible from poly(vinylamine) which is obtained from radically produced poly(vinylformamide) (PVFA) which was either immobilized onto silica surfaces from solution and converted into poly(vinylamine-co-vinylformamide) polymers (PVFA-co-PVAm) by acidic hydrolysis, or by acidic hydrolysis in solution with subsequent adsorption on. silica. we adsorbed PVFA-co-PVAm samples of different molecular masses and co-polymer compositions from aqueous solutions onto inorganic surfaces such as silica or titania simply by pH control. Direct surface functionalization using the VFA monomers was possible by their radical graft co-polymerization with bifunctional monomers, for example 1,3-divinylimidazolid-2-one (BVU) or on silica particles which were pre-functionalized with vinyltriethoxysilane (VTS). The influence of the amino content and molar mass (4000, 40,000, and 400,000 g mol(-1)) of PVFA-co-PVAm on the degree of surface coverage, charging, and polarity was studied using X-ray photoelectron spectroscopy (XPS), potentiometric titrations, and electrokinetic measurements, and solvatochromic probes. it was shown that the amino content of the co-polymer has a significant influence on the amount of polymer adsorbed, the layer thickness, and surface polarity. Post-functionalization reactions with isocyanates or fullerene were used as a suitable method for enhancing the stability of the polyelectrolyte layer on the inorganic surface. They also open the way to producing multi-functional hybrid materials. The adsorption and post-functionalization of PVFA-co-PVAm samples onto gold-coated silicon wafer surfaces was used to build up laterally patterned surfaces for sensors and biological applications.

X-ray photoelectron spectroscopy (XPS) was used to detect the bonding between a silica particle surface and attached silanes. In addition to the commonly recorded Si 2p spectrum, the Si 1 s level is also accessible when monochromatic Ag Lα X-rays are applied. Furthermore, the spectrum of the Si 1 s level shows a fine structure. After spectrum deconvolution, we assigned the fitted spectral peaks to Si–C bonds of the silanes and to the Si–O bonds of the silica network. The recorded Si 1 s spectra were deconvoluted into peaks originating from Si–C bonds and the Si–O–Si silica network. To check the results of spectrum deconvolution, several differently functionalized silanes containing stoichiometric amounts of heteroatoms were applied for silica surface modification. We conclude that spectra deconvolution of the Si 1 s signal is an appropriate means for quantification of surface attached silane molecules.

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Pyridinium N‐Phenoxide Betaines and Their Application for the Characterization of Solvent Polarities, XVIII. – Synthesis and UV/Vis Spectroscopic Properties of a Negatively Solvatochromic Pyridinium N‐Thiophenoxide Betaine DyeSynthesis and UV/Vis spectroscopic properties of the negatively solvatochromic, relative to 1 homomorphic, thiobetaine dye 2 are described. The new thiobetaine 2 exhibits an even larger negative solvatochromism and thermochromism than the standard betaine dye 1, which has been used to establish an empirical scale of solvent polarity, the so‐called ET(30) scale. Surprisingly, there exists a linear correlation between the ETO(30) values of 1 and the ETS(30) values of 2 for both aprotic and protic solvents, despite of the fact that sulfur is usually known to act as worse hydrogen‐bond acceptor than oxygen. Possible reasons for this extraordinary behaviour of 2 are discussed. In contrast to 2, the sulfo‐substituted betaine dye 4 does not exhibit any solvatochromism.

Pyridinium N‐Phenoxide Betaines and Their Application for the Characterization of Solvent Polarities, XIII. — Extension of the ET(30) Polarity Scale by 44 Organic SolventsEmpirical solvent polarity parameters ET(30), determined by means of the negatively solvatochromic betaine dye 1, are given for 44 organic solvents of current interest (Table 1).