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Presents a study which examined the microstructure of photodeposited iron (Fe) in porous Vycor glass by x-ray microprobe analysis. Analysis of the aggregation that occurs during photolysis; Identification of Fe compounds by photolysis; Adsorption and distribution of Fe in the glass; Chemical structure of the Fe aggregates.

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]

Focuses on a study which examined impregnating transition metallic compounds into porous glass as a way to form ultrafine particles in a glass matrix. Methodology of the study; Results and discussion; Conclusion.

The authors show that the thickness of spin cast nanocomposite polystyrene/clay films displays a large radial dependence that is not explained by current models. Transmission electron microscopy and atomic force microscopy reveal a tendency for the high aspect ratio clay particles to align in the direction of shear. Near the center of rotation, particles remain randomly oriented leading to the formation of voids as the film dries. They present a two dimensional numerical model that incorporates both hydrodynamic and orientation effects and accurately fits the thickness data over a wide range of filler concentrations and spin rates. [ABSTRACT FROM AUTHOR]

We report a method for producing stable low-density polymer films by using supercritical carbon dioxide (scCO[sub 2]). Two different molecular weight polystyrene films with various thicknesses were exposed to scCO[sub 2] along the density fluctuation ridge in P–T phase diagram. The swollen structures could be then frozen by flash evaporation of CO[sub 2] without forming additional voids. X-ray reflectivity data clearly showed that exposure to scCO[sub 2] could be used to produce uniform low-density films of about 2R[sub g] thick or less, where R[sub g] is radius of polymer gyration. © 2003 American Institute of Physics. [ABSTRACT FROM AUTHOR]

A novel time-of-flight detector system for He+ forward recoil spectrometry which improves the depth resolution to better than 35 nm has been used to investigate the form of the surface enrichment profile in a protonated (normal) polystyrene (PS)/deuterated polystyrene (d-PS) blend. The volume fraction [lowercase_phi_synonym] of d-PS depends on the depth z as [lowercase_phi_synonym](z)=[lowercase_phi_synonym]∞+([lowercase_phi_synonym]1-[lowercase_phi_synonym]∞) exp(-z/ξ), where [lowercase_phi_synonym]1 and [lowercase_phi_synonym]∞ are the surface and bulk volume fractions of d-PS, respectively, and ξ is approximately the bulk correlation length, as predicted by theory. [ABSTRACT FROM AUTHOR]

Iron oxide and tin oxide have been photodeposited in porous Vycor glass and examined before and after consolidation of the glass. Scanning electron microscopy reveals that the iron oxide particles are larger than the tin oxide particles. However, small-angle x-ray scattering and Rutherford backscattering show that the glass consolidates about the iron oxide but not about the tin oxide. Photodeposition of tin oxide, which appears to chemically modify the glass surface and to prevent its consolidation, offers a means of producing highly resolved regions of porosity in the otherwise consolidated glass. [ABSTRACT FROM AUTHOR]

Provides a correction to the study 'Microstructure of Photodeposited Fe in Porous Vycor Glass,' by D. Sunil, J. Sokolov, M. H. Rafailovich; B. Kotyuzhanskii, H. D. Gafney, X. Duan, B. J. Wilkens and A. L. Hanson.

X-ray reflectivity data of polymer bilayer systems have been analyzed using a Fourier method which takes into account different limits of integration in q-space. It is demonstrated that the interfacial parameters can be determined with high accuracy although the difference in the electron density (the contrast) of the two polymers is extremely small. This method is not restricted to soft-matter thin films. It can be applied to any reflectivity data from low-contrast layer systems. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]

We have monitored the progression of the dewetting of a partially brominated polystyrene (PBrS) thin film on top of a polystyrene (PS) thin film with scanning transmission x-ray microscopy (STXM) as well as photoemission electron microscopy (PEEM). We mapped the projected thickness of each constituent polymer species and the total thickness of the film with STXM, while we determined the surface composition with PEEM. Our data show that the PBrS top layer becomes encapsulated during the later stages of dewetting and that atomic force microscopy topographs cannot be utilized to determine the contact angle between PBrS and PS. © 1998 American Institute of Physics. [ABSTRACT FROM AUTHOR]