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Synthesis and Characterization of Stimuli Responsive Block Copolymers, Self-Assembly Behavior and Applications

Description: The central theme of this thesis work is to develop new block copolymer materials for biomedical applications. While there are many reports of stimuli-responsive amphiphilic [19-21] and crosslinked hydrogel materials [22], the development of an in situ gel forming, pH responsive pentablock copolymer is a novel contribution to the field, Figure 1.1 is a sketch of an ABCBA pentablock copolymer. The A blocks are cationic tertiary amine methacrylates blocked to a central Pluronic F127 triblock copo… more
Date: December 17, 2005
Creator: Determan, Michael Duane
Partner: UNT Libraries Government Documents Department
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Molecular Self-Assembly

Description: This report is divided into two parts: a study of the glass transition in confined geometries, and formation mechanisms of block copolymer mesophases by solvent evaporation-induced self-assembly. The effect of geometrical confinement on the glass transition of polymers is a very important consideration for applications of polymers in nanotechnology applications. We hypothesize that the shift of the glass transition temperature of polymers in confined geometries can be attributed to the inhomoge… more
Date: November 1, 2001
Creator: CURRO, JOHN G.; MCCOY, JOHN DWANE; FRISCHKNECHT, AMALIE L. & YU, KUI
Partner: UNT Libraries Government Documents Department
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Aerosol-Assisted Self-Assembly of Mesostructured Spherical Nanoparticles

Description: Nanostructured particles exhibiting well-defined pore sizes and pore connectivities (1-, 2-, or 3-dimensional) are of interest for catalysis, chromatography, controlled release, low dielectric constant fillers, and custom-designed pigments and optical hosts. During the last several years considerable progress has been made on controlling the macroscopic forms of mesoporous silicas prepared by surfactant and block copolymer liquid crystalline templating procedures. Typically interfacial phenomen… more
Date: March 23, 1999
Creator: Lu, Yunfeng; Fan, Hongyou; Stump, Aaron; Ward, Timothy, L.; Rieker, Thomas & Brinker, C. Jeffrey
Partner: UNT Libraries Government Documents Department
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2001 NSLS Activity Report (National Synchrotron Light Source)

Description: The year 2001 has been another highly productive year at the NSLS, with over 2500 users, including 720 first time users, conducting nearly 1200 experiments in fields ranging from the life, materials, chemical, and environmental sciences to applied science and technology. An impressive array of highlights from this scientific activity is included in this Activity Report. They include the first demonstration of a direct structural probe of the superconducting ground state in the cuprates by utili… more
Date: May 1, 2002
Creator: Corwin, M. A.
Partner: UNT Libraries Government Documents Department
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Liquid-liquid equilibria for polymer solutions and blends, including copolymers

Description: A simplified perturbed hard-sphere-chain (PHSC) theory is applied to interpret, correlate, and (in part) predict liquid-liquid equilibria (LLE) for polymer solutions and blends, including copolymers. The PHSC equation of state uses a hard-sphere-chain reference system plus a van der Waals attractive perturbation. Three pure-component parameters are obtained from readily available thermodynamic properties. Mixture parameters are obtained using pure-component parameters, conventional combining ru… more
Date: February 1, 1995
Creator: Song, Y.; Hino, T.; Lambert, S.M. & Prausnitz, J.M.
Partner: UNT Libraries Government Documents Department
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Time-domain dynamic opto-rheology study of polymer films using step-scan FTIR time-resolved spectroscopy (S{sup 2}FTIR TRS)

Description: Step-scan Fourier transform infrared spectroscopy in conjunction with impulse stress on polymer films has been used to monitor dynamic rheological responses in real time. A novel piezo-electrically-driven polymer microrheometer was employed to apply repetitive impulses to the polymer sample while time-domain spectra were recorded. Recent results include the study of both semi-crystalline polymers such as isotactic polypropylene (iPP) and elastomers such as Estane polyester/polyurethane copolyme… more
Date: July 1, 1998
Creator: Wang, H.; Palmer, R. A.; Manning, C. J. & Schoonover, J. R.
Partner: UNT Libraries Government Documents Department
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Self-organization of OPV-PEG diblock copolymers in THF/water.

Description: Oligo(phenylenevinylene)-poly(ethyleneglycol) (OPV-PEG) diblock copolymers in tetrahydrofuran (THF) solution at concentrations of 5 to 25 gl self-assemble into rod-like structures with a radius of about 80 {angstrom} for an OPV-PEG diblock copolymer comprising 13 PV and 45 EG monomers. These aggregates consist of a liquid crystalline OPV core and a PEG shell. Addition of about 10% water to the solution induces the formation of a phase of packed rods, as revealed by a sudden and dramatic transit… more
Date: July 2, 1999
Creator: Jurban, V.; Littrell, K. C.; Thiyagarajan, P.; Wang, H. B.; Wang, H. H. & Yu, L.
Partner: UNT Libraries Government Documents Department
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Formation of PS-b-PEO/Silica Films with Flat or Curved Multi-Bilayer Mesostructures of Large-Characteristic Length Scales Prepared by Solvent Evaporation-Induced Self-Assembly

Description: Diblock/silica films with multi-bilayer vesicular mesostructures of large characteristic length scales were synthesized through evaporation-induced self-assembly of PS-b-PEO. The present system is believed to be the first to yield diblock/silica films with multi-bilayer vesicular mesostructures through solvent evaporation-induced self-assembly (EISA). The ready formation in the present system is argued to be the polydispersity of polymer chains.
Date: November 22, 2000
Creator: Yu, Kui; Brinker, C. Jeffrey; Hurd, Alan J. & Eisenberg, Adi
Partner: UNT Libraries Government Documents Department
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Biomimetic Nanocomposites of Calcium Phosphate and Self-Assembling Triblock and Pentablock Copolymers

Description: In an effort to mimic the growth of natural bone, self-assembling, micelle and gel-forming copolymers were used as a template for calcium phosphate precipitation. Because of the cationic characteristics imparted by PDEAEM end group additions to commercially available Pluronic{reg_sign} Fl27, a direct ionic attraction mechanism was utilized and a polymer-brushite nanocomposite spheres were produced. Brushite coated spherical micelles with diameters of {approx}40 nm, and agglomerates of these par… more
Date: August 9, 2006
Creator: Enlow, Drew Lenzen
Partner: UNT Libraries Government Documents Department
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Bridging properties of multiblock copolymers.

Description: Using self-consistent field theory, we attempt to elucidate the links between microscopically determined properties, such as the bridging fraction of chains, and mechanical properties of multiblock copolymer materials. We determine morphological aspects such as period and interfacial width and calculate the bridging fractions, and compare with experimental data .
Date: January 1, 2003
Creator: Rasmussen, K. O. (Kim O.); Kober, E. M. (Edward M.); Lookman, T. (Turab) & Saxena, A. B. (Avadh B.)
Partner: UNT Libraries Government Documents Department
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Development of Novel Polymeric Materials for Gene Therapy and pH-Sensitive Drug Delivery: Modeling, Synthesis, Characterization, and Analysis

Description: The underlying theme of this thesis is the use of polymeric materials in bioapplications. Chapters 2-5 either develop a fundamental understanding of current materials used for bioapplications or establish protocols and procedures used in characterizing and synthesizing novel materials. In chapters 6 and 7 these principles and procedures are applied to the development of materials to be used for gene therapy and drug delivery. Chapter one is an introduction to the ideas that will be necessary to… more
Date: August 27, 2002
Creator: Anderson, Brian Curtis
Partner: UNT Libraries Government Documents Department
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Engineered monodisperse mesoporous materials

Description: Porous materials technology has developed products with a wide variety of pore sizes ranging from 1 angstrom to 100`s of microns and beyond. Beyond 15{angstrom} it becomes difficult to obtain well ordered, monodisperse pores. In this report the authors describe efforts in making novel porous material having monodisperse, controllable pore sizes spanning the mesoporous range (20--500 {angstrom}). They set forth to achieve this by using unique properties associated with block copolymers--two line… more
Date: August 1, 1997
Creator: Saunders, R. S.; Small, J. H.; Lagasse, R. R.; Schroeder, J. L. & Jamison, G. M.
Partner: UNT Libraries Government Documents Department
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Dynamic opto-rheological study of estane copolymers using step-scan FTIR spectroscopy

Description: Polyurethane copolymers generally consist of linear segments of polyurethane and polyester (or polyether). At room temperature, these polymers undergo a micro-phase separation, in which the polyurethane segments form hard domains while the polyester segments form relatively soft domains that act as the crosslinks between the hard cores. A wide variety of techniques has been utilized to characterize the microscopic (molecular) structure of polymeric materials. Recently, the dynamic infrared opto… more
Date: July 1, 1998
Creator: Wang, H.; Palmer, R. A.; Graff, D. K. & Schoonover, J. R.
Partner: UNT Libraries Government Documents Department
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MEAN FIELD AND MONTE CARLO MODELING OF MULTIBLOCK COPOLYMERS

Description: The authors discuss and apply extensions needed to treat multiblock copolymers within the mean field theoretical framework for microphase separation in diblock copolymer metals, originally due to Leibler. The mean field calculations are complemented by lattice Monte Carlo realizations using the bond fluctuation model. They find that the microphase separation transition occurs at larger {sub {chi}}N as the number of blocks in increased beyond two (i.e., beyond diblock), and that the characterist… more
Date: January 1, 2001
Creator: RASMUSSEN, K. & AL, ET
Partner: UNT Libraries Government Documents Department
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Microphase separation in a model graft copolymer

Description: We present a preliminary overview of our work on a series of graft copolymers having poly(ethyl acrylate) backbones with pendant chains of polystyrene (PS). The copolymer system appeared to be in the strong segregation limit and exhibited evidence of ordered structures. The morphology of these structures can apparently be very different from what would be expected. For instance, we observed a lamellar structure in a material containing 28 wt.% PS grafts. Samples under uniaxial strain showed eit… more
Date: October 1, 1993
Creator: Dozier, W.D.; Thiyagarajan, P. & Peiffer, D.G.
Partner: UNT Libraries Government Documents Department
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Probing the interaction of amphiphilic triblockcopolymers with a biomimetic membrane.

Description: In the last several years, there has been growing interest in the use of synthetic surfactants to augment cellular repair. Amphiphilic triblock copolymers such as PEO-PPO-PEO have been demonstrated to aid in the repair of a variety of cells. In spite of the reported success of these compounds in clinical trials, the mechanism of their interaction with cell membranes remains poorly understood. In this work, they describe their efforts to examine the effect of the mode of incorporation of tribloc… more
Date: February 4, 2002
Creator: Firestone, M. A. & Seifert, S.
Partner: UNT Libraries Government Documents Department
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New adhesive systems based on functionalized block copolymers

Description: The goal of this work was to evaluate chemically-functionalized block copolymers as adhesion promoters for metal/thermoset resin interfaces. Novel block copolymers were synthesized which contain pendant functional groups reactive toward copper and epoxy resins. In particular, imidazole and triazole functionalities that chelate with copper were incorporated onto one block, while secondary amines were incorporated onto the second block. These copolymers were found to self-assemble from solution o… more
Date: May 1, 1997
Creator: Kent, M.; Saunders, R.; Hurst, M.; Small, J.; Emerson, J. & Zamora, D.
Partner: UNT Libraries Government Documents Department
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Analysis of a polyurethane elastomer using thermal 2D FT-IR

Description: Polyurethane-polyester elastomers contain hard and soft domains which give these materials unique structural and elastic properties and lead to their use in various applications. It is desirable to characterize the molecular-level interactions giving rise to the two domains and to use this information to monitor chemical changes which take place in the polymer as a function of exposure to agents known to effect structural changes. Infrared spectroscopy has been used to study polymeric structure… more
Date: July 1, 1998
Creator: Graff, D. K.; Wrobleski, D. A.; Marsh, A. L.; Kober, E. M.; Smith, M. E. & Schoonover, J. R.
Partner: UNT Libraries Government Documents Department
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Off-specular x-ray scattering studies of the morphology of thin films

Description: We discuss the scattering of x-rays from thin films at a surface or interface decorated with a morphology of islands and how these effects manifest themselves in the specular reflectivity and the diffuse (off-specular) scattering. We show how this technique has been used to study block copolymer films decorated with islands on the surface and the development of electrochemically induced pitting on a Cu electrode in an electrolyte solution.
Date: September 1, 1996
Creator: Sinha, S.K.; Feng, Y.P. & Melendres, C.A.
Partner: UNT Libraries Government Documents Department
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Responsive copolymers for enhanced petroleum recovery. Quarterly technical progress report, September 22, 1993--December 22, 1993

Description: Synthetic efforts have focused on the development of ionically modified polymers based on monomers which contain an acrylamido functionality. The monomers may possess either cationic or anionic functionality which, depending on the pH of the polymer solution, may either be ionically charged or neutral. Thus, by adjusting the pH, the degree of ionization of the polymer may be controlled which will in turn influence the rheological behavior. Previous research in our laboratories has revealed that… more
Date: December 31, 1993
Creator: McCormick, C. & Hester, R.
Partner: UNT Libraries Government Documents Department
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Synthesis and self-assembly of fluorocarbon- and hydrocarbon-modified hydrophilic polymers. Final report

Description: Over the past 3 years, work was done in several areas: effect of spacer lengths on degree of association of hydrophobically modified polyacrylamides; fluorocarbon mediated association of R{sub F}- substituted polyacrylamide-2-(acrylamido)-2-methyl-propane sodium sulfonate copolymers; hydrophobic association in R{sub F}(R{sub H})-modified poly(N,N-dimethylacrylamide)(PDMA) and polyvinylpyrrolidone; synthesis of R{sub F}-containing poly(N- isopropyl acrylamide)`s; synthesis of HM narrow MWD telec… more
Date: November 1, 1996
Creator: Hogen-Esch, T.E.
Partner: UNT Libraries Government Documents Department
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[Synthesis and characterization of novel associating water-soluble copolymers]: Annual progress report, November 15, 1993-November 15, 1994

Description: A large number of hydrophobically associating copolymers of N-vinylpyrrolidone (NVP) or N,N-dimethyl acrylamide (DMA) with perfluoroalkyl acrylates (FOSA) containing between .01 and 1.0 mole % FOSA (with respect to DMA) were synthesized by emulsion and by bulk copolymerization. In contrast with the acrylamide (AM) FOSA copolymers the corresponding NVP and DMA copolymers are soluble in THF and CH{sub 3}OH in addition to water. This is expected to be of help in the characterization. This report d… more
Date: December 31, 1994
Partner: UNT Libraries Government Documents Department
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Responsive Copolymers for Enhanced Petroleum Recovery

Description: The objectives of this work were to: synthesize responsive, amphiphilic systems; characterize molecular structure and solution behavior; measure rheological properties of the aqueous fluids including behavior in fixed geometry flow profiles and beds; and to tailor final polymer compositions for in situ rheology control under simulated reservoir conditions. This report focuses on the first phase of the research emphasizing synthesis and the development of photophysical techniques and rheological… more
Date: June 13, 2000
Creator: McCormick, Charles & Hester, Roger
Partner: UNT Libraries Government Documents Department
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Small angle neutron scattering study of the micelle structure of amphiphilic block copolymers

Description: The amphiphilic block copolymers of vinyl ether were prepared by living cationic polymerization. The partially deuterated copolymers for SANS experiments were especially synthesized by introducing deuterated phenyl units in the hydrophobic chain. SANS measurements were performed for aqueous solutions of these copolymers by changing H{sub 2}O/D{sub 2}O ratios. The SANS profiles indicate that the micelles in the present system exhibit a core-shell structure and that the size and shape of micelles… more
Date: July 31, 1994
Creator: Yamaoka, H.; Matsuoka, H.; Sumaru, K.; Hanada, S.; Imai, M. & Wignall, G. D.
Partner: UNT Libraries Government Documents Department
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