Engineering Commons^™

A Simple And Robust Approach To Reducing Contact Resistance In Organic Transistors, Zachary A. Lamport, Katrina J. Barth, Hyunsu Lee, Eliot Gann, Sebastian Engmann, Hu Chen, Martin Guthold, Iain Mcculloch, John E. Anthony, Lee J. Richter, Dean M. Delongchamp, Oana D. Jurchescu

Chemistry Faculty Publications

Efficient injection of charge carriers from the contacts into the semiconductor layer is crucial for achieving high-performance organic devices. The potential drop necessary to accomplish this process yields a resistance associated with the contacts, namely the contact resistance. A large contact resistance can limit the operation of devices and even lead to inaccuracies in the extraction of the device parameters. Here, we demonstrate a simple and efficient strategy for reducing the contact resistance in organic thin-film transistors by more than an order of magnitude by creating high work function domains at the surface of the injecting electrodes to promote channels …

Polyhedral Oligomeric Silsesquioxane-Phosphate Glass Matrix Nanocomposites With Additional Chapter On Phosphate Glass-Poly(Ethylene Terephthalate) Matrix Composites, Kyoungtae Kim

Dissertations

Preparation and characterization of tin fluorophosphate glass (Pglass) matrix nanocomposites incorporating polyhedral oligomeric silsesquioxane (POSS) were investigated on the structural, thermal, morphological, mechanical, and rheological properties. Various processes including synthesis, extrusion and sintering processes were applied to prepare the nanocomposite samples. Another application of POSS with hydrophobic functional groups on the well-structured nanoscale silicate cage with three silanol groups was investigated to present the feasibility to use POSS molecule as a coating material on the surface of the hydrophilic inorganic glass. In addition, Poly(ethylene terephthalate) polymer matrix composites incorporating Pglass was studied to present the benefits of the Pglass with …

Hydrogen Bond Mediated Water Structuring, Diffusion, And Elastic Properties In Acrylamide Copolymer Glycohydrogels, April Levu Fogel

Dissertations

Glycohydrogels have recently gained considerable interest as biocompatible and high water content hydrogels that have similar physicochemical nature to the cell membrane, making them ideal materials for targeted biomedical and personal care applications (e.g., drug delivery systems, biosensors, and contact lenses). Regardless of the specific application, water-polymer and water-water hydrogen bonding interactions have been shown to dictate hydration stability and diffusional properties in traditional hydrogel architectures (e.g., crosslinked HEMA). However, due to the development of glycohydrogel materials within the past two decades, most literature focuses on synthetic techniques and general hydration characteristics. Furthermore, scant literature examines the effect of hydrophobically …

Improving Ductility Of Slender Reinforced Concrete Shear Walls With Frp Sheets And Splay Anchors, Luke M. Ostrom

Architectural Engineering

The Sylmar earthquake of 1971 caused significant damage to slender, non-ductile reinforced concrete (RC) shear wall buildings in California. A later survey by the Concrete Coalition in 2011, under the guidance of EERI members, indicated that there are over 3000 vulnerable concrete buildings in California [8]. This led to City of Los Angeles (LA) Ordinance 193893 enacted in 2015, which requires mandatory upgrades to these concrete buildings by 2035. Current practice to meet the requirements of this ordinance, with respect to RC wall buildings, involves adding new shear walls to the building plan or increasing the cross-sectional area of existing …

Water Processable N-Type Organic Semiconductor, Ruben S. Riquelme, Matthew Collins Weisenberger, Camila F. Gomez

Center for Applied Energy Research Faculty Patents

The present invention concerns a water-processable n-type semiconductor comprised of polyvinylpyrrolidone (PVP), carbon nanotubes (CNTs) and poly(ethyleneimine) (PEI). The semiconductors are prepared by providing PVP and CNTs in a hydrophilic slurry and dispersing therein small amounts of PEI.

Mechanical Characterization Of Expanded Polystyrene Spheres Embed Sandwich Composites For Packaging Applications, Maheswaran R, Arockia Reemas S

Journal of Applied Packaging Research

This paper addresses on study of development of new packaging material comprising Expanded Polystyrene Spheres (EPS) embedded epoxy polymer based sandwich composites with aluminium skin. The density of the packing material is controlled by varying the volume of embedded spheres. In this study, the Flexural and Compression performance of Expanded Polystyrene Spheres (EPS) embedded polymer based sandwich composites with aluminium skin are investigated. The EPS volume percent in the core is 25% with epoxy matrix which makes the the density less than 1 g/cm3 for the composite. The fabricated Sandwich Composite are very light weight, the density is less than …

Controlled Nanomorphology Of Hybrid Organic/Inorganic Multi-Component Composites Through Cooperative Non-Covalent Interactions, Lingyao Meng

Shared Knowledge Conference

Hybrid organic–inorganic nanocomposite polymers, with inorganic nanoparticles embedded in organic matrix have emerged as a special category of multifunctional materials. With rational materials design, these hybrids can show the synergistic effect of the properties from both phases. Homogenous dispersion and orderly arrangement of the organic and inorganic components are key in their functionalities. By controlling the interface and corresponding interfacial interactions between the organic and inorganic entities, we have developed a logical approach to form stable and controlled hybrid nanofiber structures. We demonstrate the formation of hybrid polymer/quantum dots (or iron oxide nanoparticles) nanocomposites through non-covalent interactions (hydrogen bonding, ionic …

Cementitious Sensors Exhibiting Stopbands In Acoustic Transmission Spectra, Shreya Vemuganti

Shared Knowledge Conference

Ultrasonic monitoring in cementitious materials is challenging due to the high degree of attenuation. In wellbore environments, monitoring becomes more challenging due to inaccessibility. Meta materials, also known as acoustic bandgap materials, exhibit an interesting feature of forbidding the propagation of elastic/sound waves and isolate vibration in a certain frequency band. Traditionally, acoustic bandgap materials are developed with inclusions such as tin, aluminum, gold, steel in a polymer matrix. In this study, we present the development of three-dimensional cementitious sensors capable of exhibiting stopbands in the acoustic transmission spectra using carbon nanotubes. Relatively wide stopbands were engineered using Floquet-Bloch periodic …

Engineering High Performance Epoxy Thermosets Using Next-Generation Impact Modification, Madhura Pawar

Doctoral Dissertations

Optimization of fracture toughness of high T_g thermosets was done through systematic investigation of different formulations of reactive functional modifiers using soft particle impact modification. Important parameters like particle size, interparticle distance (IPD) were varied by altering cure kinetics and modifying the molecular architecture of the additives. The best performing systems showed an increase in fracture toughness of 70-80% with an optimum R_p of 1.3 μm and IPD of 0.4 μm at 15 vol% impact modifier. In addition, a new platform of using block copolymer blends was studied for its feasibility to achieve non-spherical morphology for effective impact …

Fabrication Of High Refractive Index, Periodic, Composite Nanostructures For Photonic And Sensing Applications, Irene Howell

Doctoral Dissertations

This dissertation examines methods of fabricating high refractive index, periodic structures and their applications. Structures with a refractive index periodicity in one-dimensionally are fabricated by stacking layers of (high-refractive index) nanoparticle-filled and unfilled layers. More complex two- and three-dimensional structures are fabricated by direct printing of nanoparticles via solvent-assisted soft nanoimprint lithography. Polymer-nanoparticle composites are an active area of research and development especially for photonic applications. We show use of two composite formulations, first for fabrication of one-dimensional photonic crystals, and second for scalable UV-nanoimprinting. One dimensional photonic crystals, which possess a periodicity in refractive index, result in a constructive …

A Systematic Investigation Of Condensation Heat Transfer Using Asymmetric Micro-Scale Surfaces, Emily Brown

LSU Master's Theses

Asymmetric surfaces been shown to inducing unidirectional motion in the Leidenfrost regime; however, very minimal research has been conducted to investigate whether these surface can enhance condensation through the same means. The investigation of heat transfer of ratchets in condensation is a relatively untapped area of study, specifically ratchets with superhydrophobic properties. Anticipated difficulty lies in creating surfaces features or coatings that retain the ratchets and can adequately sustain optimal wetting state of Cassie-Baxter required to improve heat transfer performance during condensation. This study serves to investigate whether ratchets are a feasible surface feature to enhance condensation heat transfer. First, …

Multivariate Analysis For The Quantification Of Transdermal Volatile Organic Compounds In Humans By Proton Exchange Membrane Fuel Cell System, Ahmed Hasnain Jalal

FIU Electronic Theses and Dissertations

In this research, a proton exchange membrane fuel cell (PEMFC) sensor was investigated for specific detection of volatile organic compounds (VOCs) for point-of-care (POC) diagnosis of the physiological conditions of humans. A PEMFC is an electrochemical transducer that converts chemical energy into electrical energy. A Redox reaction takes place at its electrodes whereas the volatile biomolecules (e.g. ethanol) are oxidized at the anode and ambient oxygen is reduced at the cathode. The compounds which were the focus of this investigation were ethanol (C₂H₅OH) and isoflurane (C₃H₂ClF₅O), but theoretically, the sensor …

Swelling Induced Deformation Of Thermally Responsive Hydrogels, Ying Zhou

Doctoral Dissertations

Hydrogels are crosslinked polymeric networks imbibed with aqueous solutions. They undertake dramatic volume changes through swelling and deswelling processes, which can be stimulated by factors like temperature, pH or different chemicals. These unique properties render hydrogels particularly interesting for shape morphing related applications. In this thesis, we focus on the swelling induced deformation of thermally responsive hydrogels with lower critical solution temperatures (LCSTs), including poly(N-isopropylacrylamide) (PNIPAm) and poly(N,N-diethylacrylamide) (PDEAm). Particularly, benzophenone containing monomers are copolymerized with NIPAm or DEAm to create photocrosslinkable temperature-responsive polymers, which allows fabrication of hydrogels with controlled shapes and crosslinking …

Extreme Indentation And Fracture Of Soft Polymer Gels, Shruti Rattan

Doctoral Dissertations

The mechanical properties of conventional hard materials, such as metals and ceramics, have received widespread attention in the past several decades; however mechanical characterization, failure in particular, of soft materials, such as polymer gels, elastomers, and biological tissues and organs, has largely been ignored. While practical issues such as difficulty in handling, processing, and slippage offer complexities in characterization, the breakdown of the fundamental assumptions of linear elastic fracture mechanics due to large strains prior to failure, significant energy dissipation ahead of a crack tip and rate and time dependent effects makes understanding of failure in soft materials even more …

Increasing Organic Semiconductor Performance Through Chemical And Processing Modifications, Edmund Burnett

Doctoral Dissertations

This thesis focuses on tuning molecular packing of organic semiconductors through processing or chemical modifications to increase performance and establish structure-property relationships. Chapter 2 utilizes differing processing techniques to alter the molecular packing of bistetracene in the thin film and thorough polymorph characterization to relate the modification of molecular packing to the increase in charge mobility and mechanism. Chapter 3 introduces the oligomer as a model system to resolve issues that would be difficult or impossible using polymeric systems, due to their monodispersity and increased crystallinity allows for more detailed structural characterization. In this chapter we determine a crystal packing …

Magnetic Ordering In A Vanadium-Organic Coordination Polymer Using A Pyrrolo[2,3-D:5,4-D']Bis(Thiazole)-Based Ligand, Yulia A. Getmanenko, Christopher S. Mullins, Vladimir N. Nesterov, Stephanie Lake, Chad Risko, Ezekiel Johnston-Halperin

Chemistry Faculty Publications

Here we present the synthesis and characterization of a hybrid vanadium-organic coordination polymer with robust magnetic order, a Curie temperature T_C of ∼110 K, a coercive field of ∼5 Oe at 5 K, and a maximum mass magnetization of about half that of the benchmark ferrimagnetic vanadium(tetracyanoethylene)_~2 (V·(TCNE)_~2). This material was prepared using a new tetracyano-substituted quinoidal organic small molecule 7 based on a tricyclic heterocycle 4-hexyl-4H-pyrrolo[2,3-d:5,4-d′]bis(thiazole) (C₆-PBTz). Single crystal X-ray diffraction of the 2,6-diiodo derivative of the parent C₆-PBTz, showed a disordered hexyl chain and …

Three-Dimensional Forming Of Multi-Layered Materials: Material Heat Response And Quality Aspects, Sami-Seppo Ovaska, Pavel Geydt, Ville Leminen, Johanna Lyytikäinen, Sami Matthews, Panu Tanninen, Malte Wallmeier, Marek Hauptmann, Kaj Backfolk

Journal of Applied Packaging Research

The micro- and macrostructural changes occurring in multi-layered substrates during three-dimensional forming were studied by atomic force microscopy (AFM), scanning electron microscopy (SEM) and optical analyses. Particular attention was paid to heat-induced deformations at the interface between of polymeric coating layer and the paperboard. With excessive heat transfer, occasional delamination of polyethylene terephthalate (PET) coating from the paperboard was observed. The mechanism behind delamination was studied in detail in-situ with an AFM at temperatures relevant to the converting process. Based on the analysis, the delamination could partially be linked to the widening of the initially-existing nano-scale cracks at the coating-paperboard …

Chemically Modified Cellulosic Materials As Multi-Functional Agents In Polymer Composites, Jinlong Zhang

LSU Doctoral Dissertations

Comparative flame retardancy of micro wood fiber plastic composites (WPCs) with fire retardants (1,2-bis(pentabromophenyl) ethane, metal hydroxides and nanoclay) was studied. The fire additives (1,2-bis(pentabromophenyl) ethane as well as magnesium hydroxide) obviously enhanced the fire retarding properties of WPCs. Especially, 1,2-bis(pentabromophenyl) ethane significantly reduced the total heat release as well as heat release rate. In addition, a synergistic effect of 1,2-bis(pentabromophenyl) and nanoclay was achieved for the enhanced fire retarding performance of WPCs.

A copolymer of cellulose nanocrystals (CNCs) and poly(N-vinylcaprolactam) (PVCL) (PVCL-g-CNCs) for use as thermally-responsive polymers with low critical solution temperatures (LCSTs) was synthesized via atom transfer radical …

Chemical Modification Of Lignin Into Advanced Materials, Soheil Hajirahimkhan

Electronic Thesis and Dissertation Repository

Fossil fuel resources are being used today for most of humankind’s energy and chemical/material needs. The inevitable demise of these resources has created significant interest in the field of biomass and particularly, lignin valorization. As the world’s second most abundant polymer, more than 98% of the annually produced lignin is under-utilized either as an on-site heat source, or as landfill. Thus, finding practical approaches to modifying this inexpensive sustainable resource into materials of high value can be the next leap in lessening the dependence on fossil fuel resources and thus, developing a sustainable future.

In this thesis, kraft lignin is …

Microinjection Molding Of Carbon Filled Polymer Composites, Shengtai Zhou

Electronic Thesis and Dissertation Repository

There has been increasing demand for microparts in the areas of electronics, automotive, biomedical and micro-electro-mechanical systems. Microinjection molding (μIM) is becoming an important technology to fabricate miniature products or components to satisfy the ever-increasing needs of the above industries. Polymers and polymeric composites are ubiquitously adopted as molding materials due to their weight advantage, good processability and excellent resistance to corrosion.

Earlier studies have been primarily focused on the μIM of unfilled thermoplastics; however, microparts with multi-functionalities, such as electrical, thermal and mechanical properties are always accommodated by using multi-functional filler loaded polymer composites. Recently, μIM of carbon nanotubes …

Gnygrens18.Pdf, Garrett Nygren

Garrett Nygren

Light Intensity-Induced Phase Transitions In Graphene Oxide Doped Polyvinylidene Fluoride, Yuri A. Barnakov, Omari Paul, Akinwunmi Joaquim, April Falconer, Richard Mu, Vadim Y. Barnakov, Dmitriy Dikin, Vitalii P. Petranovskii, Andre Zavalin, Akira Ueda, Frances Williams

Electrical and Computer Engineering Faculty Research

The coupling of light with low-frequency functionalities of dielectrics and liquid crystals and an ability to turn “on” and “off” the pyro-, piezo-, or ferro- electric properties of materials on demand by optical means leads to fascinating science and device applications. Moreover, to achieve all-optical control in nano-circuits, the coupling of the light with mechanical degrees of freedom is highly desirable and has been elusive until recently. In this work, we report on the light intensity-induced structural phase transitions in graphene oxide doped piezoelectric polyvinylidene fluoride (PVDF) film observed by micro-Raman spectroscopy. Increasing the laser power results in a steady …

Thienoisatin Oligomers As N-Type Molecular Semiconductors, Natalie M. Kadlubowski, Xuyi Luo, Jianguo Mei

The Summer Undergraduate Research Fellowship (SURF) Symposium

Organic field effect transistors (OFETs) offer many advantages compared to traditional inorganic transistors, such as flexibility and solution processability. In this study we design and synthesize two thienoisatin-based organic semiconducting small molecules, then investigate their electronic properties in n-type OFETs. To introduce n-type charge transport, electron-withdrawing dicarbonitrile moieties were installed on thienoisoindigo and bis-thienoisatin molecules, which led to a quinoidal conjugation on thienoisoindigo, while maintaining an aromatic conjugation on the bis-thienoisatin. Following the syntheses, the molecules were characterized to determine highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) levels via cyclic voltammetry, as well as any potential …

Validation Of Wrinkling-To-Delamination Adhesion Measurement Technique, Allison Chau, Hyeyoung Son, Chelsea S. Davis

The Summer Undergraduate Research Fellowship (SURF) Symposium

Polymer thin films have a wide range of applications that span several different industries. Their optical clarity as well as their mechanical rigidness result in their versatile use in applications such as contact lenses, wearable sensors, and flexible electronics. These applications require precise adhesion, so the need for a simple, quantitative adhesion measurement technique is critical. Several methods have already been developed that quantify the adhesion of flexible thin films attached to rigid substrates. However, when the thin films are rigid and the substrates compliant, these methods are insufficient. In the authors’ previous work, an adhesion measurement technique was developed …

Developing Strategies To Toughen Bio-Inspired Adhesives, Narelli P. Narciso, Samuel Lee Huntington, Jonathan J. Wilker

The Summer Undergraduate Research Fellowship (SURF) Symposium

Mussels and other marine creatures adhere very well in underwater environments, having the ability to withstand the force of the sea. These animals have inspired synthetic biomimetic adhesives for wet systems, presenting potential for biomedical applications. However, most current commercial adhesives tend to be brittle, not resisting repetitive movements. This study assesses toughening strategies to improve the mussel-inspired adhesives’ ductility while maintaining its strength. The strategies included altering the polymer’s chemical structure by changing the percentage of polyethylene glycol (PEG) in the molecule and by adding fillers, such as calcium carbonate, silica and nacre - a calcium carbonate compound found …

New Methods For Understanding And Controlling The Self-Assembly Of Reacting Systems Using Coarse-Grained Molecular Dynamics, Stephen Thomas

Boise State University Theses and Dissertations

This research aims at developing new computational methods to understand the molecular self-assembly of reacting systems whose complex structures depend on the thermodynamics of mixing, reaction kinetics, and diffusion kinetics. The specific reacting system examined in this study is epoxy, cured with linear chain thermoplastic tougheners whose complex microstructure is known from experiments to affect mechanical properties and to be sensitive to processing conditions. Mesoscale simulation techniques have helped to bridge the length and time scales needed to predict the microstructures of cured epoxies, but the prohibitive computational cost of simulating experimentally relevant system sizes has limited their impact. In …

Engineering Next Generation Anisotropic Materials And Composites, Nihal Kanbargi

Doctoral Dissertations

Polymer-based composite systems have been developed for a wide variety of applications ranging from aerospace to electronics. My work has focused on the structure-process-property relationships of anisotropic polymeric materials and composites, aimed primarily for structural applications. Anisotropic materials such as fibers have superior mechanical properties along the axial direction and this property can be exploited to engineer exceptionally strong and light materials. In the first chapter, we discuss the physics of degradation of Poly(p-phenylene-2,6-benzobisoxazole) (PBO) fibers. PBO, a fiber of extraordinary tensile modulus and strength has been found to degrade rapidly under moderate conditions of humidity and heat. Solid-state NMR …

Imaging The Three-Dimensional Orientation And Rotational Mobility Of Fluorescent Emitters Using The Tri-Spot Point Spread Function, Oumeng Zhang, Jin Lu, Tianben Ding, Matthew D. Lew

Electrical & Systems Engineering Publications and Presentations

Fluorescence photons emitted by single molecules contain rich information regarding their rotational motions, but adapting single-molecule localization microscopy (SMLM) to measure their orientations and rotational mobilities with high precision remains a challenge. Inspired by dipole radiation patterns, we design and implement a Tri-spot point spread function (PSF) that simultaneously measures the three-dimensional orientation and the rotational mobility of dipole-like emitters across a large field of view. We show that the orientation measurements done using the Tri-spot PSF are sufficiently accurate to correct the anisotropy-based localization bias, from 30 nm to 7 nm, in SMLM. We further characterize the emission anisotropy …

Microstructural Characterization Of Shear Transformation Zones And Modeling Indentation Size Effect In Amorphous Polymers, Leila Malekmotiei

LSU Doctoral Dissertations

The first aim of this work is developing a procedure for experimental and analytical characterization of nano-scale microstructures which mediate large scale deformation in amorphous polymers. Glassy polymers are extensively used as high impact resistant, low density, and clear materials in industries. Nevertheless, their response under severe loading conditions is yet to be appropriately unraveled. Due to the lack of long-range order in the microstructures of glassy solids, their plastic deformation is different from that in crystalline solids. Shear Transformation Zones (STZs) are believed to be the main plasticity carriers in amorphous solids and defined as the localized atomic or …

Glucosamine From Hydrolysis Of 3d Printing Chitosan For Osteoarthritis Treatment, Ruj Dansriboon, Laphon Premcharoen

The International Student Science Fair 2018

This project aims to introduce a new way for osteoarthritis treatment which is expected to increase in the future. Glucosamine is the main subject for a treatment, which can be derived by hydrolyzing chitosan. This project also includes extraction of chitosan from shrimp waste to make a worthy use of food waste from industry. In this project, 3D printer is applied to print chitosan gel since 3D printing is adjustable to form various shapes of the gel.

The research process begins with the extraction of chitosan from shrimp shells. For the next step, the percent of deacetylation of chitosan was …