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Learning From "Coffee Rings": Ordered Structures Enabled By Controlled Evaporative Self-Assembly, Wei Han 2012 Iowa State University

Learning From "Coffee Rings": Ordered Structures Enabled By Controlled Evaporative Self-Assembly, Wei Han

Graduate Theses and Dissertations

Drying droplets containing nonvolatile solutes (polymers, microspheres, nanoparticles, single-walled carbon nanotubes, DNA, etc.) on a solid surface have been utilized to yield self-assembled, dissipative structures, possessing dimensions of a few hundred submicrons and beyond. However, these dissipative structures created via evaporation are often irregular and far from equilibrium. Yet for many applications in microelectronics, data storage devices, and biotechnology, it is highly desirable to achieve surface patterns that have a well-controlled spatial arrangement. To date, only a few elegant studies have centered on establishing a means of harnessing the drying process of an evaporating droplet to produce highly regular structures ...


Sustainability Through Blockcopolymers: Novel Ion Exchange Cathode Membranes And Soybean Oil Based Thermoplastic Elastomers, Nacú Bernardo Hernández-Cantú 2012 Iowa State University

Sustainability Through Blockcopolymers: Novel Ion Exchange Cathode Membranes And Soybean Oil Based Thermoplastic Elastomers, Nacú Bernardo Hernández-Cantú

Graduate Theses and Dissertations

This work studies the sustainable use of blockcopolymers (BCPs) in aims to reduce dependency in oil. This work focused on the design and development of new materials that can provide "green" substitutes to petroleum based products. Our two main areas of interest are: alternative power sources, more specifically polymer electrolyte fuel cells (PEFCs), and the synthesis of vegetable oil based thermoplastic elastomers. Research on PEFCs focused on developing a new cathode catalyst layer membrane comprised of a mesoporous block copolymeric nanocomposite that will satisfy (1) electrical conductivity, (2) proton conductivity, (3) oxygen transport in, (4) and water transport out via ...


Developing Benzobisazole-Containing Conjugated Polymers For Semiconducting Applications, Jeremy Joseph Intemann 2012 Iowa State University

Developing Benzobisazole-Containing Conjugated Polymers For Semiconducting Applications, Jeremy Joseph Intemann

Graduate Theses and Dissertations

Benzobisazoles are electron deficient moieties whose polymers are known to possess high thermal and mechanical strength. To date, howeverm they have not been well developed for semiconducting applications due to their poor solubility in organic solvents and an inability to functionalize these materials. This thesis describes the synthesis and properties of a variety of new benzobisazole-containing conjugated polymers and reports their performance in organic light-emitting diodes. The new polymers are soluble in common organic solvents and have been synthetically tuned to possess a wide variety of properties by copolymerizing benzobisazole with an assortment of different comonomers. Furthermore, the first examples ...


Nanoscale Toughness And Behavior Of Graphene/Epoxy Interfaces, Nima Rahbar, Hossein Salahshoor 2011 Worcester Polytechnic Institute

Nanoscale Toughness And Behavior Of Graphene/Epoxy Interfaces, Nima Rahbar, Hossein Salahshoor

Nima Rahbar

Atomistic simulations are performed to investigate the nano-scale interfacial fracture toughness between graphene and epoxy. Nano-mechanical properties of graphene and epoxy are initially studied using molecular dynamics simulations. A novel method is suggested to accurately model the behavior of the graphen/epoxy interface during the curing process of the epoxy as a function of temperature. The computed interfacial fracture energy is computed at about 0.203 J/m2, which is in good agreement with available experimental data. It is also shown that the adhesion between cured epoxy and graphene layer increases the pre-existing waviness of the 2-dimensional graphene sheet in ...


Polymer Nanocomposite Analysis And Optimization For Renewable Energy And Materials, Nathan Walter Henry 2011 University of Tennessee, Knoxville

Polymer Nanocomposite Analysis And Optimization For Renewable Energy And Materials, Nathan Walter Henry

Doctoral Dissertations

Polymer nanocomposites are an important research interest in the area of engineering and functional materials, including the search for more environmentally materials for renewable energy and materials. The ability to analyze and optimize morphology is crucial to realizing their potential, since the distribution of materials in the composite strongly influences its properties. This dissertation presents research into three different polymer nanocomposite systems with three different applications that underscore the need to understand and control the composite morphology to succeed.

The first project details work on development of a copolymer compatibilizer to enhance the dispersion of the plant-derived biopolymer lignin in ...


Effects Of Molecular Architecture On Fluid Ingress Behavior Of Glassy Polymer Networks, Matthew Blaine Jackson 2011 University of Southern Mississippi

Effects Of Molecular Architecture On Fluid Ingress Behavior Of Glassy Polymer Networks, Matthew Blaine Jackson

Dissertations

This manuscript demonstrates the synthesis of glassy polymer network isomers to control morphological variations and study solvent ingress behavior independent of chemical affinity. Well-controlled network architectures with varying free volume average hole-sizes have been shown to substantially influence solvent ingress within glassy polymer networks. Bisphenol-A diglycidyl ether (DGEBA), bisphenol-F diglycidyl ether (DGEBF), Triglycidyl p-aminophenol (pAP, MY0510), Triglycidyl maminophenol (mAP, MY0610), and tetraglydicyl-4,4’-diamino-diphenyl methane (TGDDM, MY721) were cured with 3,3’- and 4,4’-diaminodiphenyl sulfone (DDS) at a stoichiometric ratio of 1:1 oxirane to amine active hydrogen to generate a series of network architectures with an average ...


Design Of Covalently Dynamic Films And Coatings: Analysis Of Biocatalyzed Kinetic Behavior In Soft Condensed Matter, Pirro Cipi 2011 University of Southern Mississippi

Design Of Covalently Dynamic Films And Coatings: Analysis Of Biocatalyzed Kinetic Behavior In Soft Condensed Matter, Pirro Cipi

Dissertations

Reversibly adjusting surface and bulk properties of materials is advantageous to many applications and will vastly expand current polymer capabilities. A novel strategy was developed to render materials capable of “smart” surface and bulk properties with the aid of embedded biocatalyst and latent functional groups that are selectively activated in the presence of biocatalyst to undergo chemical transformation. The research presented herein focused on systematically characterizing the activity of lipase catalysts embedded in poly (alkyl methacrylate)s simultaneously with functionalized components, either as diffusing within the polymeric matrix or tethered to the matrix. Lipase activity, ester forming (synthetic) or ester ...


The Investigation Of Asphaltene-Naphithenic Acid And Asphaltene-Surface Interactions, David Tristan Heaps 2011 University of Southern Mississippi

The Investigation Of Asphaltene-Naphithenic Acid And Asphaltene-Surface Interactions, David Tristan Heaps

Dissertations

Asphaltenes represent a ubiquitous problem in the oil industry due to their adverse effects on recovery, production, and processing equipment. These problems have affected oil companies throughout the world, resulting in significant financial losses. In order to expand the existing body of knowledge related to asphaltenes, we have examined how the presence of naphthenic acids contributes to the particle aggregation and sedimentation behavior of asphaltene suspensions as well as how the physics and chemistry of a substrate affect asphaltene adsorption/deposition.

The flocculation of asphaltenes in the presence of naphthenic acids was investigated using dynamic light scattering (DLS), near-infrared spectroscopy ...


Development And Utilization Of Digital Image Correlation Techniques For The Study Of Structural Isomerism Effects On Strain Development In Epoxy Network Glasses, Stephen Robert Heinz 2011 University of Southern Mississippi

Development And Utilization Of Digital Image Correlation Techniques For The Study Of Structural Isomerism Effects On Strain Development In Epoxy Network Glasses, Stephen Robert Heinz

Dissertations

The specific aim of this dissertation is to present the findings regarding the effects of molecular structure on macroscopic mechanical performance and strain development in epoxy networks. Network molecular structure was altered through monomer isomerism and crosslink density/molecular weight between crosslinks. The use of structural isomerism provided a pathway for altering mechanical performance while maintaining identical chemical composition within the network. Isomerism was investigated primarily by the curing of diglycidyl ether of bisphenol A (DGEBA) using either the para- or meta-substituted derivatives of diaminodiphenyl sulfone (DDS). Additional insights into isomerism were gained through the investigation of networks composed of ...


Physical And Electrical Properties Of Trimetallic Nitride Template Endohedral Metallofullerenes And Their Polymer Nanocomposites, Hanaa Mohammed Ahmed 2011 University of Southern Mississippi

Physical And Electrical Properties Of Trimetallic Nitride Template Endohedral Metallofullerenes And Their Polymer Nanocomposites, Hanaa Mohammed Ahmed

Dissertations

The main objective of this study was characterization of pure metallic nitride fullerene, MNF, and MNF containing polymers to evaluate these materials as suitable devices for tunable applications. Polymer-fullerene nanocomposites consisting of linear polyurethane (PU) segments crosslinked via polyhydroxylated fullerenes (C60 and Sc3N@C80, a metallic nitride fullerene) were prepared and characterized for their mechanical and dielectric properties using dynamic mechanical analysis (DMA) and broadband dielectric spectroscopic techniques. Polyhydroxylated fullerenes C60(OH)29 and Sc3N@C80(OH)18 were synthesized in a high yield through a solid-state high sheer ball-milling procedure and ...


Synthesis And Characterization Of Acceptor: Donor Block Copolymers For Organic Photovoltaics, Brandon Cory Achord 2011 University of Southern Mississippi

Synthesis And Characterization Of Acceptor: Donor Block Copolymers For Organic Photovoltaics, Brandon Cory Achord

Dissertations

Mankind needs sources of clean power. Photovoltaic (PV) cells, in use since 1839, have proven reliable and practical for certain applications. PV cell efficiency has changed over the years from 1-2% to ultra-high efficiency cells operating at efficiencies greater than 40%. Organic photovoltaics are a potential transformative technology platform. The potential for cell use, efficiency and cost are all parts of the research and development focus at the time this document was written. This research was initiated with a focus on the synthesis and understanding of the variables effecting acceptor-donor block copolymer. The self-assembled morphology resulting from varying volume ratios ...


Free Volume Studies Of Various Polymeric Systems Using Positron Annihilation And Pvt-Eos Analyses, Mukul Kaushik 2011 University of Southern Mississippi

Free Volume Studies Of Various Polymeric Systems Using Positron Annihilation And Pvt-Eos Analyses, Mukul Kaushik

Dissertations

The glass transition phenomenon and free volume behavior below and above the glass transition temperature of various polymeric systems have been investigated. Several novel polymeric systems were considered for this study. Two generations of hyperbranched polyols, H40 and H20, were selected due to large number of hydroxyl groups on the periphery and within the bulk. The effect of hydrogen bonds and molecular weight was related with the glass transition and free volume behavior for the whole range of experimental temperature. The free volume behavior was experimentally studied using PVT and PALS to determine occupied volume, fractional free volume and number ...


Synthesis Of An Antimicrobial Textile Coating, William M. Morris 2011 California Polytechnic State University, San Luis Obispo

Synthesis Of An Antimicrobial Textile Coating, William M. Morris

Chemistry and Biochemistry

A titania nanosol was synthesized and coated onto nylon/cotton blended textile substrates. The substrates were characterized via SEM for adhesion and nanoparticle formation, then subjected to antimicrobial efficacy tests. The titania nanosol was successfully coated on to textiles samples. Particles were observed to be around 2 by 3 micrometers and formed between the interstitial space of textile fibers. Although larger than typical nanoparticles, the coatings exhibited what seemed to be antimicrobial activity. Titania nanosol coated textile samples were subjected to Kirby Bauer Assay in the presence of S. aureus. The coated textile sample exhibited an inhibition of growth around ...


Chemical Modification On Gold Slides To Gain Better Control Of Patterning Techniques, Ragini Vuppalapati 2011 Western Kentucky University

Chemical Modification On Gold Slides To Gain Better Control Of Patterning Techniques, Ragini Vuppalapati

Masters Theses & Specialist Projects

Nanolithography is a rapidly evolving field that requires new combinations of techniques to improve patterning and to assist in fabricating electromechanical devices. An increasing number of applications require surfaces with defined regions of different chemical functionality. In our previous project optimum conditions for lithographic patterning were determined and potential blockers were identified to reduce force on the tip.

This work is focused on identifying good chemical modifications that will allow better control of basic patterning and to investigate the minimum force of patterning required while using each chemical system. The primary aim is to gain better control of basic pattern ...


Adhesion And Durability Of Coatings On Polypropylene Exterior Sidings, Logan Riekio Stark 2011 California Polytechnic State University - San Luis Obispo

Adhesion And Durability Of Coatings On Polypropylene Exterior Sidings, Logan Riekio Stark

Master's Theses and Project Reports

Plastics have become a universal material for use in a myriad of commercial and consumer products. One such product, exterior siding, is the focus of this project. Although siding products were originally made from wood, vinyl siding, which offered superior performance, was introduced in the 1950’s. More recently, polypropylene (PP) siding has been introduced; PP provides a stronger product, which allows for deeper patterns and better edge detailing. PP siding, compared to traditional wood siding, doesn’t warp, crack, or degrade as easily with extended exposure to the elements, and is cheaper to maintain. However, even plastic siding must ...


Wetting Properties Induced In Nano-Composite Poss-Ma Polymer Films By Atomic Layer Deposited Oxides, Kyle A. Vasquez, Anita J. Vincent-Johnson, W. Chris Hughes, Brian H. Augustine, Kyoungmi Lee, Gregory N. Parsons, Giovanna Scarel 2011 James Madison University

Wetting Properties Induced In Nano-Composite Poss-Ma Polymer Films By Atomic Layer Deposited Oxides, Kyle A. Vasquez, Anita J. Vincent-Johnson, W. Chris Hughes, Brian H. Augustine, Kyoungmi Lee, Gregory N. Parsons, Giovanna Scarel

Department of Physics and Astronomy - Faculty Scholarship

Due to their unique properties, nano-composite polyhedral oligomeric silsequioxane (POSS) copolymer films are attractive for various applications. Here we show that their natural hydrophobic character can become hydrophilic when the films are modified by a thin oxide layer, up to 8 nm thick, prepared using atomic layer deposition. A proper choice of the deposition temperature and thickness of the oxide layer are required to achieve this goal. Unlike other polymeric systems, a marked transition to a hydrophilic state is observed with oxide layers deposited at increasing temperatures up to the glass transition temperature (∼110 °C) of the POSS copolymer film ...


Nir-Emissive Polymersomal Markers For Molecular-Level Detection Of Metastasis, Wei Qi 2011 University of Pennsylvania

Nir-Emissive Polymersomal Markers For Molecular-Level Detection Of Metastasis, Wei Qi

Publicly Accessible Penn Dissertations

Noninvasive imaging technologies, capable of visualizing early carcinoma or dormant or latent metastatic tumor cells and evaluating the efficacy of cancer therapies are becoming increasingly important. In this thesis, NIR-emissive polymersomes are engineered for optimal cellular uptake to enable fluorescence-based tumor targeting. A series of benzothiadiazole conjugated porphyrin oligomers with high emission dipole strength and exceptional large quantum yields in the NIR region are synthesized for optimized emissive output would be greatly enhanced. Furthermore, this thesis established for the first time a class of universal chemistry modification methods to directly attach antibody to polymersomes surface with very high antibody coupling ...


Reintroducing Explicit Solvent To A Solvent-Free Coarse-Grained Model, Seung Ha Kim, Monica H. Lamm 2011 Iowa State University

Reintroducing Explicit Solvent To A Solvent-Free Coarse-Grained Model, Seung Ha Kim, Monica H. Lamm

Chemical and Biological Engineering Publications

A unique coarse-grained modeling scheme that combines a systematic, solvent-free multiscale coarse-graining algorithm for a complex macromolecule with an existing coarse-grained solvent model is proposed. We show that this procedure efficiently and reliably describes the interactions for complex macromolecules, using the specific example of dendrimers binding phenanthrenes in water. The experimentally measured binding capacity is predicted by the unique coarse-grained modeling approach; the conditions for this simulation are beyond what could be reasonably simulated with an all-atom molecular dynamics simulation.


Introduction To Molecular Motion In Polymers (Book Review), Jeffrey H. Glans 2011 Sacred Heart University

Introduction To Molecular Motion In Polymers (Book Review), Jeffrey H. Glans

Chemistry & Physics Faculty Publications

A book review by Jeffrey H. Glans.

Pethrick, Richard A., T. Amornsakchai, and A. M. North. Introduction to Molecular Motion in Polymers. Dunbeath, Scotland: Whittles Pub.; Boca Raton, FL: Distributed in North America by CRC, 2011.

ISBN 9781849950084


Self-Repairable Polymeric Networks: Synthesis And Network Design, Biswajit Ghosh 2011 University of Southern Mississippi

Self-Repairable Polymeric Networks: Synthesis And Network Design, Biswajit Ghosh

Dissertations

This dissertation describes the design, synthesis and development of a new class of polymeric networks that exhibit self-repairing properties under UV exposure. It consists of two parts: (a) modification and synthesis of oxetane (OXE), and oxolane (OXO) substituted chitosan (CHI) macromonomer, and (b) design, and synthesis of self-repairing polyurethane (PUR) networks consisting of modified chitosan. Unmodified CHI consisting of acetamide (-NHCOCH3), primary hydroxyl (-OH), and amine (-NH2) functional groups were reacted with OXE or OXO compounds under basic conditions in order to substitute the 1° –OH groups, and at the same time, convert -NHCOCH3 functionalities into -NH ...


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