Compounds are provided which can form bioabsorbable compositions useful as adhesives or sealants for medical/surgical applications.

Bioabsorbable surgical composition

Mass spectrometry of polymers and polymer surfaces.

Fluoroelastomers: synthesis, properties and applications

Zerovalent iron (nZVI) nanoparticles have long been used in the electronic and chemical industries due to their magnetic and catalytic properties. Increasingly, applications of nZVI have also been reported in environmental engineering because of their ability to degrade a wide variety of toxic pollutants in soil and water. It is generally assumed that nZVI has a core-shell morphology with zerovalent iron as the core and iron oxide/hydroxide in the shell. This study presents a detailed characterization of the nZVI shell thickness using three independent methods. High-resolution transmission electron microscopy analysis provides direct evidence of the core-shell structure and indicates that the shell thickness of fresh nZVI was predominantly in the range of 2-4 nm. The shell thickness was also determined from high-resolution X-ray photoelectron spectroscopy (HR-XPS) analysis through comparison of the relative integrated intensities of metallic and oxidized iron with a geometric correction applied to account for the curved overlayer. The XPS analysis yielded an average shell thickness in the range of 2.3-2.8 nm. Finally, complete oxidation reaction of the nZVI particles by Cu(II) was used as an indication of the zerovalent iron content of the particles, and these observations further correlate the chemical reactivity of the particles and their shell thicknesses. The three methods yielded remarkably similar results, providing a reliable determination of the shell thickness, which fills an essential gap in our knowledge about the nZVI structure. The methods presented in this work can also be applied to the study of the aging process of nZVI and may also prove useful for the measurement and characterization of other metallic nanoparticles.

Determination of the oxide layer thickness in core-shell zerovalent iron nanoparticles.

The ionic insulating properties of n-alkylthiol self-assembled monolayers (SAMs) and a related fluorinated SAM are characterized by electrochemical ac impedance spectroscopy CH3(CH2)nS/Au (n = 7−15) SAMs prepared via prolonged incubation in a thiol solution obey the Helmholtz ideal capacitor model and thus are virtually defect-free The electrochemical properties of SAM-coated electrodes are compared with those of a bare gold electrode The phase angle at an ion-diffusion-related frequency (1 Hz) is ≥ 88° and is independent of the electrolyte concentration The thiol chains act as a dielectric material whose impedance (modulus) is 105 Ω cm2 at 1 Hz Both the phase angle and the complex dielectric constant in the low-frequency region are good indicators of the film's ability to act as an ionic insulator

Insulating Properties of Self-Assembled Monolayers Monitored by Impedance Spectroscopy

Valinomycin-mediated transport of alkali cations through solid supported membranes

Ar plasma treated and Al metallised polycarbonate: a XPS, mass spectroscopy and SFM study

A series of monodisperse poly(styrene-b-isoprene[-g-perfluoroacyl]) block copolymers was synthesized by sequential anionic polymerization of styrene and isoprene. The perfluorinated ester side chains were attached to the remaining double bonds of the isoprene block via oxidative hydroboration and esterification of the resulting alcohol by the corresponding perfluorinated acid chloride. Surfaces of the pure polymers or blends in polystyrene exhibit a notable fractional surface excess of the perfluorinated side chains within the uppermost 100 A depending on the surface preparation and the block copolymer composition. Thus, these surfaces are highly hydrophobic having advancing water contact angles of up to 122°. When samples are heated to 340 °C, the perfluorinated side chains can be selectively cleaved off by a thermal ester cleavage, leaving the backbone of the polymer completely intact. As a result, the hydrophobicity of the resulting poly(styrene-b-isoprene) polymer surface is reversed to an advancing w...

Selectively thermally cleavable fluorinated side chain block copolymers : Surface chemistry and surface properties

Overlayer thickness determination by angular dependent X-ray photoelectron spectroscopy (ADXPS) of rough surfaces with a spherical topography

The present invention relates to composite materials made of at least one composite layer of a polyurethane and of a second composite layer which is directly bonded to the first layer and which consists of a thermoplastic material that is different from the polyurethane of layer A). The polyurethane material of layer A) is characterized by a residual content of free reaction components containing ether groups of no more than 400 ppm, and preferably of no more than 100 ppm. The invention also relates to a process for the production of these composite materials and to a method of their use as materials in motor vehicles.

Stable adhesive composite material made of polyurethane and of another thermoplastic material, a process for its production and a method for its use in motor vehicles

Karsten Reihs

Papers

Valinomycin-mediated transport of alkali cations through solid supported membranes

Ar plasma treated and Al metallised polycarbonate: a XPS, mass spectroscopy and SFM study

Selectively thermally cleavable fluorinated side chain block copolymers : Surface chemistry and surface properties

Overlayer thickness determination by angular dependent X-ray photoelectron spectroscopy (ADXPS) of rough surfaces with a spherical topography

Stable adhesive composite material made of polyurethane and of another thermoplastic material, a process for its production and a method for its use in motor vehicles