Polymer and Organic Materials Commons^™

Poly(Pyridinium Salt)S Containing 9,9-Bis(4- Aminophenyl)Fluorene Moieties With Various Organic Counterions Exhibiting Both Lyotropic Liquid-Crystalline And Light-Emitting Properties, Pradip K. Bhowmik, David King, Haesook Han, Andras F. Wacha, Matti Knaapila

Chemistry and Biochemistry Faculty Research

Main-chain conjugated and non-conjugated polyelectrolytes are an important class of materials that have many technological applications ranging from fire-retardant materials to carbon-nanotube composites, nonlinear optical materials, electrochromic materials for smart windows, and optical sensors for biomolecules. Here, we describe a series of poly(pyridinium salt)s-fluorene containing 9,9-bis(4-aminophenyl)fluorene moieties with various organic counterions that were synthesized using ring-transmutation polymerization and metathesis reactions, which are non-conjugated polyelectrolytes. Their chemical structures were characterized by Fourier transform infrared (FTIR), proton (1H) and fluorine 19 (19F) nuclear magnetic resonance (NMR) spectrometers, and elemental analysis. They exhibited polyelectrolytic behavior in dimethyl sulfoxide. Their lyotropic liquid-crystalline phases were …

Heated Assembly And Transfer Of Van Der Waals Heterostructures With Common Nail Polish, Kristine L. Haley, Jeffrey A. Cloninger, Kayla Cerminara, Randy M. Sterbentz, Takashi Taniguchi, Kenju Watanabe, Joshua O. Island

Physics & Astronomy Faculty Research

Recent advances in the manipulation and control of layered, two-dimensional materials has given way to the construction of heterostructures with new functionality and unprecedented electronic properties. In this study, we present a simple technique to assemble and transfer van der Waals heterostructures using common nail polish. Commercially available nail polish acts as a resilient sticky polymer, allowing for the fabrication of complex multi-material stacks without noticeable fatigue. Directly comparing four commercially available brands of nail polish, we find that one stands out in terms of stability and stacking characteristics. Using this method, we fabricate two top-gated devices and report their …

Two New Finite Element Schemes And Their Analysis For Modeling Of Wave Propagation In Graphene, Jichun Li

Mathematical Sciences Faculty Research

© 2020 The Author(s) In this paper, we investigate a system of governing equations for modeling wave propagation in graphene. Compared to our previous work (Yang et al., 2020), here we re-investigate the governing equations by eliminating two auxiliary unknowns from the original model. A totally new stability for the model is established for the first time. Since the finite element scheme proposed in Yang et al. (2020) is only first order in time, here we propose two new schemes with second order convergence in time for the simplified modeling equations. Discrete stabilities inheriting exactly the same form as the …

A Soft-Robotic Harbor Porpoise Pectoral Fin Driven By Coiled Polymer Actuators As Artificial Muscles, Robert Hunt, Sarah Trabia, Zakai Olsen, Kwang Kim

Mechanical Engineering Faculty Research

Biomimicry is an approach in science and engineering to overcome human challenges by designing materials and systems modeled after nature. Selected applications of biomimicry include catheters, hearing devices, and artificial appendages such as arms, legs, and fingers. The inspiration for this study is the hydrofoil-like structured pectoral fin of the harbor porpoise whale that is ultimately useful for studying fluid-structure interactions, drag, lift, and laminar-to-turbulent transitions. The pectoral fin is fabricated by manipulating computed tomography (CT) scans into 3D models using Simpleware ScanIP and post-processed in Autodesk for printing. An array of thermally driven coiled polymer actuators (CPA) fabricated from …

Applied Analysis Of Ionic Polymer Metal-Composite Actuators, Siul Ruiz, Benjamin Mead, Woosoon Yim

College of Engineering: Graduate Celebration Programs

• IPMC is a type of smart material called an electroactive polymer
• Consists of an ionic polymer such as Nafion or Flemion and a conducive metal such as platinum or gold
• COMSOL multi-physics simulations accurately model the experimental displacement results
• Optimization performed using the multi-physics model to find the maximum deflection, force, and twisting
• Using the closed loop control system accurate IPMC tip location can be achieved
• This control system has been extended to function using a computer mouse as an input

Modeling And Control Of A Flexible Ionic Polymer Metal Composite(Ipmc) Actuator For Underwater Propulsion, Shivakanth Gutta

UNLV Theses, Dissertations, Professional Papers, and Capstones

The goal of this research is to model and control the underwater vehicle propelled by IPMC actuator. IPMC consists of an ionic membrane sandwiched between two metallic electrodes. When an external voltage is applied, IPMC undergoes large deformation due to transport of ions. Due to its ability to work in aqueous environments, it can be used for developing small scale underwater vehicles.

First, Finite element approach is used to describe the dynamics of the both single and segmented IPMC actuator. In the approach presented, each element is attached with a local coordinate system that undergoes rigid body motion along with …

Direct Contact Pyrolysis Of Hydrocarbons: A Source Of Hydrogen And Interesting Carbon Formations, Peter G. Faught

UNLV Theses, Dissertations, Professional Papers, and Capstones

The work detailed in this document looks at a novel liquid metal supported catalytic system for the generation of hydrogen by decomposition of ethanol through direct contact pyrolysis. The hydrogen is produced at relatively low temperatures (500-600°C) and has carbon and water as co-products. It should be noted that CO is not observed as a product at these low temperatures. This is to be contrasted with the hydrogen produced at higher temperature from ethanol which does contain carbon monoxide. The presence of carbon monoxide in hydrogen complicates fuel cell operation and catalytic chemical processes. Thus, the lack of CO in …

Creep In Photovoltaic Modules: Examining The Stability Of Polymeric Materials And Components, David C. Miller, Michael D. Kempe, Stephen H. Glick, Sarah R. Kurtz

Publications (E)

Interest in renewable energy has motivated the implementation of new polymeric materials in photovoltaic modules. Some of these are non-cross-linked thermoplastics, in which there is a potential for new behaviors to occur, including phase transformation and visco-elastic flow. Differential scanning calorimetry and rheometry data were obtained and then combined with existing site-specific time-temperature information in a theoretical analysis to estimate the displacement expected to occur during module service life. The analysis identified that, depending on the installation location, module configuration and/or mounting configuration, some of the thermoplastics are expected to undergo unacceptable physical displacement. While the examples here focus on …

Raman Studies Of 1,3,5,7 Cyclooctatetraene At High Pressure, Martin Galley, Ed Romano, Sergey Tkachev, Michael Pravica

Undergraduate Research Opportunities Program (UROP)

We performed Raman spectroscopic studies of 1,3,5,7-cyclooctatetraene at elevated pressures up to 10 GPa with the aim of examining possible planarization of the molecule and further studying two prior-discovered phases of the solid with pressure. The Raman excitation source was a Krypton-ion laser operating at 674.1 nm (give wavelength).

1,3,5,7 Cyclooctatetraene has an octagonal formation however it is not aromatic or anti-aromatic (not a subject to the 4n+2 Huckel’s rule) [1]. As a result, its adopts a somewhat reactive tub shape. Upon the addition or removal of one to two electrons under ambient conditions, the molecule planarizes and becomes aromatic …