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Selective deuteration combined with X-ray and neutron reflectivity has been used to determine the extent of probe segregation to an interface in ultra-thin polymer films as a function of the [...]

X-ray microprobe analysis, Mossbauer spectroscopy and extended x-ray absorption fine structure spectroscopy, EXAFS, are used in the examination of the UV photolysis of Fe(CO)5 physisorbed onto porous Vycor glass. Two different forms of iron are revealed by the spectroscopic data although the photolysis and consequent heating are carried out in air. One of the iron products is similar to alpha-Fe203 and consists of an Fe3+ ion surrounded by six oxygen atoms, and is indicated by isomer shift, pre-edge and EXAFS data.

Patterns of submicron cobalt islands were created on silicon by using self-assembled co-polymers as etching masks. The synthesis conditions were varied to create specific magnetic island morphologies. The magnetic structure and magnetization reversal of interconnected, as well as interacting and non-interacting islands were systematically studied using magnetic force microscopy. Differences in magnetic characteristics were observed and correlated with the thin film morphologies. The result of these studies include the transition from single to multidomain configuration as a function of island size, domain boundary characteristics near coercivity, evidence of magnetization rotation with increasing reverse magnetic field, and evidence of collective switching behavior in interacting single domain islands.

We report measurements and calculations of x-ray diffuse scattering from the liquid–vapor interface of toluene and polybromostyrene(PBrS)/toluene solutions for polymer molecular weights 90 K and 1 M at concentrations up to 11.7 volume %, well into the entangled semidilute regime. We have calculated the static structure factor S(k) and equal time height–height correlation function C(R) for surface hydrodynamic modes based on a coupled two-fluid model where the polymer response is taken to be that of a Maxwell viscoelastic material [Harden et al., J. Chem. Phys. 94, 5208 (1991)]. We obtain the leading correction term to the capillary-wave result for C(R) dependent on the solution shear modulus E0, as well as an analytic approximation valid for large E0, including the case of pure polymer melt. [ABSTRACT FROM AUTHOR]

Symmetric diblock copolymers self-assemble spontaneously into surface micelles during adsorption onto a solid surface from a concentrated solution using a selective solvent. A two-dimensional superlattice with a high degree of in-plane ordering is formed by the micelles. A circular-to-ribbon phase transition is also noted with increasing polymer concentration. Results show that the formation of two-dimensional micelles is a reversible equilibrium process in very concentrated polymer solutions.

Fe(CO)5 is physisorbed onto porous Vycor glass (PVG) photolysed in air, and studied for Mossbauer and X-ray absorption data to prove the theory that photolysis results in photodeposition of elemental iron on PVG. The spectra show that the resultant substance is a mixture of zerovalent Fe aggregates and Fe3+, thus proving the validity of the assumption made on the photolysis of Fe(CO)5. Fe(CO)5 samples are impregnated into the PVG surface by vapor deposition.