Polymer Science Commons^™

Ion-Imprinted Polymer-Based Sensors For Toxic Metal-Ion Detection In Water: Coordination Chemistry, Transduction Strategies, And Environmental Applications, Ghita Yammouri, Gymama Slaughter

Center for Bioelectronics Publications

Toxic metal contamination in aquatic environments remains a persistent threat to human health and ecosystems. Yet, the high cost, infrastructure demands, and centralized nature of conventional analytical methods constrain routine monitoring. Ion-imprinted polymers (IIPs), a subclass of molecularly imprinted polymers, have emerged as promising synthetic recognition materials for metal-ion sensing because they generate coordination-defined binding sites with high selectivity, chemical stability, low cost, and reusability. This review summarizes recent advances in Ion-imprinted polymer (IIP)-based sensing technologies for toxic metal-ion detection in water from 2016 to 2026. It examines the fundamental recognition chemistry of IIPs, major synthesis strategies used to generate …

Polymorphism And Mechanical Behavior In Hot-Pressed 3d-Printed Polyamide Composite: Effects Of Pressure And Temperature, John Barber, Patricia Revolinsky, Jimesh Bhagatji, Diego Pedrazzoli, Sergii Kravchenko, Oleksandr Kravchenko

Mechanical & Aerospace Engineering Faculty Publications

The aim of this work is to study the effect of high-temperature compaction (HTC) upon the polymorphism and the mechanical behavior of an additively manufactured (AM) carbon fiber-reinforced polyamide (PA6). Different pressure and temperature levels during HTC were tested to determine the overall effect on the mechanical behavior and material crystalline composition. Treated, carbon fiber-reinforced PA6 samples were analyzed using differential scanning calorimetry, X-ray diffraction, thermogravimetric analysis, scanning electron microscopy, and three-point bending testing. When considered with respect to as-printed samples, an HTC temperature of 190 °C combined with 80 psi pressure resulted in an increased flexural modulus and strength …

A Comprehensive Review Of Piezoelectric Pvdf Polymer Fabrications And Characteristics, Nadia Ahbab, Sidra Naz, Tian-Bing Xu, Shihai Zhang

Mechanical & Aerospace Engineering Faculty Publications

Polyvinylidene fluoride (PVDF) polymer films, renowned for their exceptional piezoelectric, pyroelectric, and ferroelectric properties, offer a versatile platform for the development of cutting-edge micro-scale functional devices, enabling innovative applications ranging from energy harvesting and sensing to medical diagnostics and actuation. This paper presents an in-depth review of the material properties, fabrication methodologies, and characterization of PVDF films. Initially, a comprehensive description of the physical, mechanical, chemical, thermal, electrical, and electromechanical properties is provided. The unique combination of piezoelectric, pyroelectric, and ferroelectric properties, coupled with its excellent chemical resistance and mechanical strength, makes PVDF a highly valuable material for a wide …

Pla Polymer Binder In Core Production - Influence On Final Casting Dimensions, Artur Soroczyński, Krzysztof Rechowicz

Virginia Digital Maritime Center (VDMC) Faculty Publications

The foundry industry is seeking an ecological alternative to synthetic molding resins. This study evaluates the technological properties of core sands bonded with biodegradable polylactide (PLA). Cores prepared on a 2% quartz sand matrix were subjected to casting processes using two alloys with extremely different pouring temperatures: gray cast iron (approx. 1200 °C) and AK11 silumin (approx. 710 °C). The research methodology included macroscopic assessment, dimensional analysis using 3D scanning (GOM Inspect), and qualitative knock-out assessment supported by numerical temperature field simulation. The results showed that the high crystallization temperature of cast iron leads to complete thermal degradation of the …

Incorporating Insulin Into Alginate-Chitosan 3d-Printed Scaffolds: A Comprehensive Study On Structure, Mechanics, And Biocompatibility For Cartilage Tissue Engineering, Afsaneh Jahani, Mohammad Sagdegh Nourbakhsh, Ali Moradi, Marzieh Mohammadi, Lobat Tayebi

Electrical & Computer Engineering Faculty Publications

Osteoarthritis is a leading cause of disability worldwide, challenging current treatments to limited cartilage self-healing capacity. Cartilage tissue engineering (CTE) integrates cells, scaffolds, and signaling molecules, with Insulin being utilized as a differentiation biomolecule due to cost-effectiveness, dose-dependent influence on chondrogenesis, suitable biological activity, and ability to activate relevant receptors. Yet, administering differentiation biomolecules through conventional scaffolds poses a persistent challenge. Alginate (Alg) is commonly employed in CTE for its biocompatibility, though it lacks sufficient mechanical properties. Chitosan (Cs), while enhancing scaffold mechanical properties, but does not independently provide optimal support for chondrogenesis. While Alg-Cs scaffolds have garnered attention, challenges …

Quasi-Static And Impact Load Response Of Bfrp-Reinforced Concrete Beams And Post-Terrorist-Attack Sub-Assemblages, José Luis Carrasquillo

Civil & Environmental Engineering Theses & Dissertations

This dissertation presents the outcome of a theoretical and experimental study of Basalt Fiber Reinforced Polymer (BFRP) reinforced concrete beams and post-terrorist-attack subassemblages subjected to either quasi-static or impact load. Both BFRP reinforcement as well as BFRP fabric are used in this investigation. The sub-assemblage consists of an otherwise two-span beam converted to a fixed-end single-span one owing to the loss of a middle column blasted off during the terrorist attack. The simply supported beams are subjected to a midspan quasistatic or an impact load. However, each sub-assemblage is subjected to a quasi-static load up to collapse to simulate the …

Role Of Nitrogenous Functional Group Identity In Accelerating 1,2,3- Trichloropropane Degradation By Pyrogenic Carbonaceous Matter (Pcm) And Sulfide Using Pcm-Like Polymers, Han Cao, Jingdong Mao, Paul G. Tratnyek, Wenqing Xu

Chemistry & Biochemistry Faculty Publications

Groundwater contamination by 1,2,3-trichloropropane (TCP) poses a unique challenge due to its human toxicity and recalcitrance to degradation. Previous work suggests that nitrogenous functional groups of pyrogenic carbonaceous matter (PCM), such as biochar, are important in accelerating contaminant dechlorination by sulfide. However, the reaction mechanism is unclear due, in part, to PCM's structural complexity. Herein, PCM-like polymers (PLPs) with controlled placement of nitrogenous functional groups [i.e., quaternary ammonium (QA), pyridine, and pyridinium cations (py⁺)] were employed as model systems to investigate PCM-enhanced TCP degradation by sulfide. Our results suggest that both PLP-QA and PLP-py⁺ were highly effective …

4,6-O-Phenylethylidene Acetal Protected D-Glucosamine Carbamate-Based Gelators And Their Applications For Multi-Component Gels, Pooja Sharma, Guijun Wang

Chemistry & Biochemistry Faculty Publications

The self-assembly of carbohydrate-based low molecular weight gelators has led to useful advanced soft materials. The interactions of the gelators with various cations and anions are important in creating novel molecular architectures and expanding the scope of the small molecular gelators. In this study, a series of thirteen new C-2 carbamates of the 4,6-O-phenylethylidene acetalprotected D-glucosamine derivatives has been synthesized and characterized. These compounds are rationally designed from a common sugar template. All carbamates synthesized were found to be efficient gelators and three compounds are also hydrogelators. The resulting gels were characterized using optical microscopy, atomic force microscopy, …

Reducing Print Time While Minimizing Loss In Mechanical Properties In Consumer Fdm Parts, Long Le, Mitchel A. Rabsatt, Hamid Eisazadeh, Mona Torabizadeh

Mechanical & Aerospace Engineering Faculty Publications

Fused deposition modeling (FDM), one of various additive manufacturing (AM) technologies, offers a useful and accessible tool for prototyping and manufacturing small volume functional parts. Polylactic acid (PLA) is among the commonly used materials for this process. This study explores the mechanical properties and print time of additively manufactured PLA with consideration to various process parameters. The objective of this study is to optimize the process parameters for the fastest print time possible while minimizing the loss in ultimate strength. Design of experiments (DOE) was employed using a split-plot design with five factors. Analysis of variance (ANOVA) was employed to …

Strengthening Prestressed Concrete Bridge Girders And Building Beams With Carbon Fiber Reinforced Polymer Sheets, Herish A. Hussein, Zia Razzaq

Civil & Environmental Engineering Faculty Publications

The effect of Carbon Fiber Reinforced Polymer (CFRP) retrofitting and concrete type on the flexural strength of prestressed concrete I-section girders used in bridges and beams in buildings is investigated. Non-linear moment-curvature relationships are predicted using an iterative algorithm for both non-retrofitted and CFRP-retrofitted prestressed concrete girder and beam cross-sections with various concrete types. Two different CFRP-retrofitting schemes are analyzed for comparing their effectiveness. It is found that although non-retrofitted beam section exhibits greater ductility, the use of CFRP retrofitting in both tension and compression regions simultaneously results in a significant increase in flexural strength. It is also found that …

Electrochemical Hydrogenation Of Acetone To Produce Isopropanol Using A Polymer Electrolyte Membrane Reactor, Chen Li, Ashanti M. Sallee, Xiaoyu Zhang, Sandeep Kumar

Civil & Environmental Engineering Faculty Publications

Electrochemical hydrogenation (ECH) of acetone is a relatively new method to produce isopropanol. It provides an alternative way of upgrading bio-fuels with less energy consumption and chemical waste as compared to conventional methods. In this paper, Polymer Electrolyte Membrane Fuel Cell (PEMFC) hardware was used as an electrochemical reactor to hydrogenate acetone to produce isopropanol and diisopropyl ether as a byproduct. High current efficiency (59.7%) and selectivity (>90%) were achieved, while ECH was carried out in mild conditions (65 degrees C and atmospheric pressure). Various operating parameters were evaluated to determine their effects on the yield of acetone and …

Interface Model Of Pem Fuel Cell Membrane Steady-Dtate Behavior, Russell L. Edwards, Ayodeji Demuren

Mechanical & Aerospace Engineering Faculty Publications

Modeling works which simulate the proton-exchange membrane fuel cell with the computational fluid dynamics approach involve the simultaneous solution of multiple, interconnected physics equations for fluid flows, heat transport, electrochemical reactions, and both protonic and electronic conduction. Modeling efforts vary by how they treat the physics within and adjacent to the membrane-electrode assembly (MEA). Certain approaches treat the MEA not as part of the computational domain, but rather an interface connecting the anode and cathode computational domains. These approaches may lack the ability to consistently model catalyst layer losses and MEA ohmic resistance. This work presents an upgraded interface formulation …

Hydrophobic Surface Modification Of Polymethyl Methacrylate By Two-Dimensional Plasma Jet Array At Atmospheric Pressure, Feng Liu, Meiling Cai, Bo Zhang, Zhi Fang, Chunqi Jiang, Kostya Ken Ostrikov

Bioelectrics Publications

Recently developed atmospheric pressure plasma jet (APPJ) is considered as a novel and efficient technique for uneven surfaces processing and APPJ array effectively expands the treatment area of a single APPJ. In this paper, a two-dimensional (2D) APPJ array in Ar/tetramethylsilane (TMS) is used to improve the surface hydrophobicity of polymethyl methacrylate (PMMA) by depositing polymerized silicalike clusters on the jet-PMMA interface. The electrical and optical characteristics of the 2D Ar/TMS APPJ array are measured to optimize experimental conditions. The wettability of jet-PMMA interface is assessed by measuring water contact angle, which increases from 65° to a maximum value of …

Plasma Processes And Polymers Third Special Issue On Plasma And Cancer, Mounir Laroussi, Annemie Bogaerts, Nazir Barekzi

Electrical & Computer Engineering Faculty Publications

(First paragraph) This issue of Plasma Processes and Polymers is the third in a series on the applications of low temperature plasma (LTP) against cancer, or “plasma oncology.” The papers in this issue are inspired from the talks given at the third International Workshop on Plasma for Cancer Treatment (IWPCT) which took place on April 11–12, 2016 in Washington, DC, USA. IWPCT is an international workshop that was created in 2014 as a venue to share cutting edge plasma oncology research. The first IWPCT was held in Washington DC, under the co-chairmanship of Prof. Mounir Laroussi (Old Dominion University) and …

Failure Modes For I-Section Gfrp Beams, Mamadou Konate, Zia Razzaq

Civil & Environmental Engineering Faculty Publications

This paper presents calculations for the failure modes for I-section Glass Fiber Reinforced Polymer (GFRP) beams with single mid-span web brace. Theoretical predictions are made using ASCE-LFRD Pre-Standard for FRP structures. For the member length considered, it is found that for small and medium I-sections the failure mode is governed by lateral-torsional buckling and for bigger I-sections the failure mode is governed by material rupture. The outcome of the predicted lateral-torsional buckling mode is compared with that observed experimentally.

Plasma Processes And Cancer - Special Topical Cluster Of The 2nd Iwpct Meeting, Masaru Hori, Mounir Laroussi, Kai Masur, Yuzuru Ikehara

Electrical & Computer Engineering Faculty Publications

(First paragraph) Although the emerging multidisciplinary field of plasma medicine has been around for nearly two decades important advances have already taken place that could one day revolutionize healthcare and the way various challenging diseases can be treated.1-3Amongst these advances the effects of low temperature plasma (LTP) on cancer cells in vitro and in vivo stand out.4-13Current cancer treatment modalities, such as chemotherapy and radiation therapy, have serious side effects and tend to lose their benefits to the patients after a while. Therefore, novel and improved therapies that can be used alone …

Study Of Polyaniline For Use In An Organic Field Effect Transistor, Thomas Martin Sprinkle

Chemistry & Biochemistry Theses & Dissertations

Polyaniline's emeraldine base form was synthesized via chemical polymerization in HCl acidic media utilizing ammonium persulfate as the oxidant. Synthesis was done at room temperature and -30 'C and characterized for differences by X-ray diffraction, thermogravimetric analysis, and differential scanning calorimetry. Methanol soxhlet extraction was done to increase number average molecular weight from 77,400 to 81,000 and decrease the poly dispersity index from 3.82 to 2.14. Films were cast using N, N'- Dimethylpropyleneurea and N-Methylpyrrolidone and showed poor mechanical properties upon acidic doping.

Cyclic voltammetry was done with HC1 as the acidic media and an ITO coated slide as the …

Rheological Signatures In Limit Cycle Behaviour Of Dilute, Active, Polar Liquid Crystalline Polymers In Steady Shear, M. Gregory Forest, Panon Phuworawong, Qi Wang, Ruhai Zhou

Mathematics & Statistics Faculty Publications

We consider the dilute regime of active suspensions of liquid crystalline polymers (LCPs), addressing issues motivated by our kinetic model and simulations in Forest et al. (Forest et al. 2013 Soft Matter 9, 5207-5222 (doi:10.1039/c3sm27736d)). In particular, we report unsteady two-dimensional heterogeneous flow-orientation attractors for pusher nanorod swimmers at dilute concentrations where passive LCP equilibria are isotropic. These numerical limit cycles are analogous to longwave (homogeneous) tumbling and kayaking limit cycles and two-dimensional heterogeneous unsteady attractors of passive LCPs in weak imposed shear, yet these states arise exclusively at semi-dilute concentrations where stable equilibria are nematic. The results in Forest …

Plasma Processes And Polymers Special Issue On: Plasma And Cancer, Mounir Laroussi, Michael Keidar

Electrical & Computer Engineering Faculty Publications

During the last two decades, research efforts on the application of low temperature plasmas in biology and medicine have positioned nonequilibrium lowtemperature plasmas as a technology that has the potential of revolutionizing healthcare.[1,2] Low temperature plasmas can be applied in direct contact with living tissues to inactivate bacteria,[3] to disinfect wounds and accelerate wound healing,[4] and to induce damage in some cancer cells.[5–11]

Improving The Efficiency Of P3ht:Icba Organic Solar Cells By Modifying The Photoactive Solution Preparation Step, Matthew Blaine Samson

Electrical & Computer Engineering Theses & Dissertations

Organic solar cells (OSCs) are a promising alternative to conventional silicon solar cells. These organic devices offer the promise of facile low cost large scale solution based processing on lightweight, flexible, plastic substrates. At the present state of the technology, however, OSCs exhibit relatively low power conversion efficiencies. To improve these efficiencies, new materials are constantly being developed.

One such material is the fullerene indene-C₆₀ bisadduct (ICBA). When implemented in a poly(3-hexylthiophene-2, 5-diyl) (P3HT) : ICBA bulk heterojunction solar cell, these devices exhibit open circuit voltages exceeding 0.8 V, a value much higher than the devices made implementing phenyl-C …

Flexural Rigidity Characterization Of Retrofitted Frp Plates, Steven J. Makonis Jr., Stella B. Bondi, Zia Razzaq

Civil & Environmental Engineering Faculty Publications

Presented herein is a procedure and numerical results for flexural rigidity characterization of Fiber Reinforced Polymer (FRP) plates retrofitted with various types of fabrics. The FRP plates were retrofitted with Kevlar® 49 (Aramid), Carbon Fiber (Harness-Satin H5), and Unidirectional Carbon Fiber (T700 Aerospace Grade) fabrics, respectively. The FRP plate flexural rigidity values were calculated with a central finitedifference iterative scheme while utilizing the experimental load-deflection relations based on bending tests. The tests were performed on each plate by applying a concentrated load at the center. A fourth-order partial differential equation of plate equilibrium was adopted to estimate the plate flexural …

Plasma Medicine, Mounir Laroussi, Alexander Fridman

Electrical & Computer Engineering Faculty Publications

Recent demonstrations of plasma technology in the treatment of living cells, tissues, and organs are creating a newfield at the intersection of plasma science and technology with biology and medicine - Plasma Medicine.

Sublethal And Killing Effects Of Atmospheric-Pressure, Nonthermal Plasma On Eukaryotic Microalgae In Aqueous Media, Ying Zhong Tang, Xin Pei Lu, Mounir Laroussi, Fred C. Dobbs

OES Faculty Publications

In-depth studies on the interaction of nonthermal plasmas with microorganisms usually focus on bacteria; only little attention has been given to their effects on more complex eukaryotic cells. We report here nonthermal plasma's effects on cell motility, viability staining, and morphology of eukaryotic microalgae, with three marine dinoflagellates and a marine diatom as major targets. The effects on motility and viability staining depended on the time of exposure to plasma and the species of microalgae. We observed a strong pH decrease in aqueous samples (marine and freshwater algal cultures, their culture media, and deionized water) after exposure to plasma, and …

The Effects Of Electron Radiation On The Glass Transition Temperature Of A Polyetherimide, Kristen Tulloch Kern

Physics Theses & Dissertations

The effects of electron radiation on a polyetherimide (PEI), Ultem*, were investigated. In particular, the changes in the glass transition temperature (T_g) with absorbed radiation dose were studied. The polymer was exposed to mono-energetic beams of 100-keV electrons and 1.0-MeV electrons for doses up to 100 megagray (MGy). Dosimetry for the exposures was based on Monte-Carlo simulations of the transfer of energy from an energetic electron to the polymer and on comparison to Nylon standards. Dynamic mechanical analysis was used to determine the (T_g) for non-exposed PEI and the changes in (T_g) resulting from …

The Effects Of Low Doses (1 To 500 Kilograys) Of 100-Kev Electrons On Four Polymers, Cynthia Anne Bradbury

Physics Theses & Dissertations

Commercial films of polyetherimide (PEI), polyetheretherimide (PEEI), polyethylene terephthalate (PET), and polycarbonate (PC) were exposed in vacuum to l 00-keV electron radiation to total absorbed doses of l, l 0, l 00, 300, and 500 kilograys. The concentration of radiation-generated radicals, as measured by electron paramagnetic resonance (EPR), increased by over an order of magnitude in all four polymers. Correspondingly, the intensity of the infrared absorption peaks increased uniformly for all doses. Solubility tests resulted in decreased solubility in all polymers. IR, EPR, and solubility suggest dehydrogenation of the aliphatic C-H and phenyl C-H sites. The data indicated that cross …

The Synthesis Of New Maleimide Addition Polymer Precursors, Richard B. Brown

Chemistry & Biochemistry Theses & Dissertations

1H-2,3-dimethylpyrrolo(1,2-a) benzimidazol-l-one (27) and 1H,9H- 2,3,7,8-tetramethyl-bispyrrolo(1,2-a:6,7-a')benzodiimidazo1-1,9-dione (32) have been synthesized from dimethylmaleic anhydride and o-phenylenediamine and 1,2,4,5-tetraaminobenzene, respectively. The presence of reactive olefinic double bonds in the synthesized compounds was of interest as a site for possible addition polymerization.

The synthetic route involved, in both cases, a simple nucleophilic substitution reaction between the diamine(or tetraamine) and the anhydride to form an intermediate amide-acid-amine which rapidly cyclized to the imide amine. The final ring closure required more rigorous conditions and occurred at melt reaction temperatures.