WorldCat Identities


Works: 8 works in 9 publications in 1 language and 9 library holdings
Publication Timeline
Solubilization of Hydrophobic Substances into Block Copolymer Micelles in Aqueous Media and their Release( Book )

2 editions published in 1994 in English and held by 2 WorldCat member libraries worldwide

The objective of this research project was the study of properties of polymer micelles that control the uptake or release of hydrophobic species from aqueous solution. Fluorescence techniques were used to monitor the rate of equilibration of small molecule fluorophores with respect to the micelle interior. An additional goal was to characterize how the properties of the polymer influence the final micelle properties (e.g. aggregation number, hydrodynamic diameter, radius of gyration, eta.). The conditions that permit exchange of individual polymers between micelles have also been determined. Most of our work has involved polymer micelles with polystyrene cores and poly(methylmethacrylate) or poly(t-butylmethacrylate) coronas in organic solvents and poly(methacrylic acid) coronas in aqueous solution. Block Polymer micelles, Solubilization of hydrophobic release of hydrophobic species
Office of Naval Research End-of-the-Year Report: Publications/Patents/Presentations/Honors/Students Report: Chemical Reactivity Studies of High Temperature Superconductor Structures and Devices( )

1 edition published in 1995 in English and held by 1 WorldCat member library worldwide

A light surface fluorination technique is exploited to alter the properties of YBa2Cu3O(7-x) ceramic samples. Unlike previous studies where more aggressive fluorination conditions were employed and reductions in the carrier density as well as the formation of amorphous degradation phases were noted, the mild fluorination conditions reported herein can be utilized to incorporate fluorine directly into the high-Tc lattice without disruption of the basic structure. Consequently, more positive values for the copper and oxygen binding energies than seen in previous experiments by XPS are observed. Moreover, the special fluorination conditions identified here are shown to impart enhanced stability towards the adverse effects of water corrosion. jg
Single Source Precursors for the OMCVD of III/V Compound Semiconductors( )

1 edition published in 1993 in English and held by 1 WorldCat member library worldwide

The overall goals are to develop the fundamental chemistry of group III and group V compounds in several key areas. The underlying rationale is that we may be able to ultimately improve on the preparation and properties of important materials used in the semiconductor industries. The research comprises a collaboration between a synthetic inorganic chemist and a chemical engineer. The three main areas are (1) single source precursors for OMCVD of III/V semiconductors, (2) alternative precursors for OMCVD studies, group III or V hydrides, and (3) the organometallic chemistry of bismuth. The first area will employ compounds of the general type (R2M(mu-R'2E))2 (M=Al, Ga, ln; E=P, As; R, R'=alkyl, aryl, etc.) and the second will employ similar compounds but with R or R' replaced by the hydride ligand. We will explore the relationships between precursor structures, mechanisms of decomposition and thin film formation, and the morphological and electrical properties of the grown films. In the third area we will explore the organometallic chemistry of bismuth and compounds which may serve as precursors to important materials such as InBiSb. OMCVD, Precursors, Thin film formation, Organometallic
Augmentation for Research Training: Surface-Mediated Photocatalysis( )

1 edition published in 1994 in English and held by 1 WorldCat member library worldwide

Three areas have been investigated: application of esr spectroscopy and time-resolved reflectance absorption and emission spectroscopy to establish mechanisms in photocatalytic oxidative degradations of organic molecules; exploration of controlled oxidation chemistry for new heteroatom-containing organic molecules; and synthesis and characterization of new quantized semiconductor-support systems. The objectives of this project have been largely accomplished despite discontinued funding of the parent grant beyond the initial nine months, instead of the requested three years. We have successfully demonstrated that photocatalytic oxidation on irradiated semiconductor surfaces is a useful route for degradation of various organic materials under constrained, highly controlled conditions
Application of Scanning Tunneling Microscopy to Studies of Electrode Surfaces( Book )

1 edition published in 1994 in English and held by 1 WorldCat member library worldwide

This project involved the study of a variety of different surfaces and structures in gaseous and liquid environments using the scanning tunneling microscope (STM) and other scanning probe microscopes with the aim of obtaining a better understanding of electrode surfaces and the processes occuring on these surfaces. With the STM we investigated chemical changes on the surface of electrodes, e.g., corrosion, passivation, and biochemical activities, and studied the energetics for electron transfer at the surfaces of semiconductors. We also investigated nanostructures (for example, very small semiconductor particles, porous Si, and self-assembled monolayers) using this technique. Scanning tunneling microscopy (STM), Scanning probe microscopy (SPM), Semiconductor surfaces, Electrode surfaces, Nanostructures
Diffusive Transport of the Hydrated Electron: A Pseudoclassical Model( )

1 edition published in 1992 in English and held by 1 WorldCat member library worldwide

In order to elucidate the factors responsible for the enhanced diffusion rate of the hydrated electron compared to halide ions, a pseudoclassical simulation technique that mimics the adiabatic dynamical response of the electron is applied to halide-like ions in water for different solute-solvent potential models. Both the adiabatic and classical diffusive behavior are evaluated and compared to the quantum dynamics of the hydrated electron. It is shown that the adiabatic response per se is essential, but only partially responsible for the diffusion rate enhancement of the excess electron. Specific features of the solute-solvent interaction potential must also be taken into account for a realistic description of the electron mobility. These include the nature of the short range repulsion associated with the spatial confinement of the excess electron and the partial penetration of the excess electronic distribution into the first hydration shell. When these effects are also incorporated into the pseudoclassical model, both the solvated electron dynamics and solvation structure are closely reproduced by the model system
Hybridization of Block Copolymer Micelles( )

1 edition published in 1993 in English and held by 1 WorldCat member library worldwide

Block copolymers of styrene and methacrylic acid dissolved in water/ dioxane mixtures form spherical micelles with polystyrene cores and poly(methacrylic acid) shells. When two micellar solutions containing micelles made from two different copolymers are mixed, the micelles may hybridize. The hybridization was followed by the method of sedimentation velocity. The rate of hybridization was found to be a very sensitive function of the architecture of both copolymers and of the thermodynamic properties of the solvent mixture. In many instances this rate is imperceptible slow; it may be totally frozen when the solvent is very poor with respect to the micellar core. The analysis of the hybridization of numerous micellar pairs provided new insights into the dynamics and thermodynamics of unimer/micelle equilibria. (Author)
Study of Sedimentation Velocity of Block Copolymer Micelles( )

1 edition published in 1993 in English and held by 1 WorldCat member library worldwide

Sedimentation velocity experiments may provide many valuable insights into the nature and behavior of macromolecules and other particles. In this study we are reporting on sedimentation velocity of block copolymer micelles formed by diblock and triblock copolymers of styrene and methacrylic acid. These micelles are an object of a broad research in our laboratory. The synthesis of copolymers and evaluation of their molecular properties have been described elsewhere. All our copolymer samples formed micellar solutions when dissolved in a mixture of 80 vol.% of dioxane and 20 vol.% of water (80D/20W). In these systems, the polystyrene block are segregated in the micellar cores that are presumably swollen by dioxane. The methacrylic acid blocks form much looser shells surrounding these cores
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Audience level: 0.99 (from 0.99 for Solubiliza ... to 0.99 for Solubiliza ...)