Materials Chemistry Commons^™

Atom Transfer Radical Processes: From Catalyst Design To Polymer Synthesis, Characterization, And Application, Michael Novak

Electronic Theses and Dissertations

Due to the toxicity of heavy metals and their prevalence in the environment there exists a need to develop highly active transition metal catalysts ultimately reducing the amount needed for chemical transformations. Additionally, there is interest in the scientific community for creating new materials that can remove these pollutants from industrial wastewater prior to its release into the environment. The work presented here focuses on the reduction and removal of heavy metals from industrial hazardous waste by designing novel highly active catalysts and developing polymeric adsorbents.

Highly active catalyst complexes consisting of novel hybrid ligands, 2-(dimethylamino)ethyl-bis-[2-(pyridylmethyl)amine] (M1-T2), and bis[2-(dimethylamino)ethyl]-2-(pyridylmethyl)amine (M2-T1), …

Control Of Corrosion On Ss316l Using Surface Initiated Polymers, Alexander Rupprecht

Electronic Theses and Dissertations

Pitting corrosion is arguably one of the most destructive and dangerous forms of corrosion, resulting in damage to structures, the environment, and public health. In addition, damage caused to structures such as bridges, pipelines, and boats, corrosion also has a profound effect on the biomedical community. Implanted metallic devices (i.e., vascular stents and artificial joints) are prone to pitting corrosion caused by aggressive ions present in extracellular fluid. To provide a corrosion-resistant surface on SS316L, films of poly(styrene), poly(methyl acrylate), and poly(methyl methacrylate) were formed using surface-initiated atom transfer radical polymerization (SI-ATRP). The resulting hydrophobic polymer films had a fractional …

Characterizations Of Bimetallic Silver-Copper Nanoparticles, Omar Lezcano

Undergraduate Honors Theses

The goal of this study was to characterize alloy nanoparticles with different bimetallic ratios of silver (Ag) and copper (Cu) by determining the composition and alloy structures. One specific objective was to determine how the composition affects the electrical properties of the nanoparticles in terms of electrical resistance and nanoparticle sintering. The desire for this study stems from the need to make conductive pastes for low-cost solar panel manufacturing. We performed experiments to develop the aqueous synthesis of core-shell bimetallic nanoparticles.

We investigated the room temperature sintering properties with the nanoparticles of varying compositions. The nanoparticles were characterized with several …

The Analytical And Biomedical Applications Of Carbon Dots And Their Future Theranostic Potential: A Review, Sukunya Ross, Ren-Siang Wu, Shih-Chun Wei, Gareth M. Ross, Huan-Tsung Chang

Journal of Food and Drug Analysis

In recent years, carbon dots (C-dots) have gained appreciable interest owing to their unique optical properties, including tunable fluorescence, stability against photobleaching and photoblinking, and strong fluorescence. Simple and low-cost hydrothermal and electrochemical approaches have been widely used in the preparation of biocompatible and high-quality C-dots. Various C-dots have been used for the quantitation of small analytes, mostly based on analyte induced fluorescence quenching. Depending on the nature of precursors, synthetic conditions (such as reaction temperature and time), and surface conjugation, multi-function C-dots can be prepared and used in diagnostics and therapeutics. Their strong fluorescence and photostability, enables use in …

Carbon Dots As Artificial Peroxidases For Analytical Applications, Shih-Chun Wei, Yang-Wei Lin, Huan-Tsung Chang

Journal of Food and Drug Analysis

Nanozymes have become attractive in analytical and biomedical fields, mainly because of their low cost, long shelf life, and less environmental sensitivity. Particularly, nanozymes formed from nanomaterials having high surface area and rich active sites are interesting since their activities can be tuned through carefully controlling their size, morphology, and surface properties. This review article focuses on preparation of carbon dots (C dots) possessing peroxidase-like activity and their analytical applications. We highlight the important roles of the oxidation states and surface residues of C dots and their nanocomposites with metal, metal oxides, or metal sulfides playing on determining their specificity …

Functionalized Gold Nanoparticles For Sensing Of Pesticides: A Review, Wei-Bin Tseng, Ming-Mu Hsieh, Che-Hsie Chen, Tai-Chia Chiu, Wei-Lung Tseng

Journal of Food and Drug Analysis

Pesticides are a family of non-biodegradable chemical compounds which widely used in agriculture to control pests and increase yield production. However, overuse or abuse of pesticides and their metabolites may cause potential toxicity for the environment as well as human health and all other living organisms, even at deficient concentrations. Consequently, the development of sensors for monitoring these compounds is significant. Recently, nanoparticles-based sensors have been extensively employed as a potential alternative or complementary analytical tool to conventional detection methods for pesticides. Among them, gold nanoparticles (AuNPs) owing to their unique optical properties have been developed as smart sensors with …

Practical Adhesion Measurements In Organic Coatings; Advancing Understanding And Mechanical Methods Development, Diana Gottschalk

Dissertations

“Adhesion” can be considered either a mechanical or chemical phenomenon. The mechanical interpretation describes the difficulty of separating surfaces and is useful for quantifying performance within applications that depend on bulk and interfacial properties. Chemical adhesion describes interfacial resistance to chemical attack and does not depend on bulk properties. Predicting chemical failure through mechanical measurement is confounded by the influence of bulk properties. However, the prospect is attractive because of the robust tolerance for sample geometries, allowing experiments to resemble an end-use system. The present work's primary goal was to elevate mechanical methods to provide a detailed interfacial characterization of …

Strain Control Of Layer-Resolved Negative Capacitance In Superlattices, Raymond Walter, Sergey Prosandeev, Charles Paillard, L. Bellaiche

Physics Faculty Publications and Presentations

Negative capacitance in BaTiO₃/SrTiO₃ superlattices is investigated by Monte Carlo simulations in an atomistic effective Hamiltonian model, using fluctuation formulas for responses to the local macroscopic field that incorporates depolarizing fields. We show that epitaxial strain can tune the negative capacitance of the BaTiO₃ ferroelectric layer and the overall capacitance of the system. In addition, we predict and explain an original switching of the negative capacitance from the BaTiO₃ layer to the SrTiO₃ layer at low temperatures for intermediate strains.

Design, Synthesis And Application Of Janus Gold Nanoprisms For Directed Self-Assembly., Md. Emtias Chowdhury

Electronic Theses and Dissertations

Colloidal Janus particles that possess more than one type of surface chemistry or functionalities have drawn significant interest due to their enormous potential in bottom-up synthetic strategies for complex superstructures. Moreover, the property of molecular recognition, tunability, and predictability of the DNA-mediated interactions enable a high degree of control over particle assembly to generate highly ordered nanostructures with emergent applications. In this dissertation, we present our works on the synthesis of Janus particles from anisotropic gold nanoprisms, and DNA- mediated assembly of nanoprisms and polymer beads in four major areas: 1) Facet selective asymmetric functionalization of gold nanoprisms for Janus …

Study On Cation Exchange Of A Lead Coordination Polymer Targeting Dynamic Mixed Cation Doped And Mixed-Valent Coordination Polymers, Hamisu Aliyu Mohammed

Student Works (2020-2029)

Solid solution in Metal-Organic Coordination Polymers (MOCPs) is an emerging synthetic pathway for modifying chemical compositions and has been expansively investigated. It has been demonstrated to be an important tool for engineering novel functional materials that otherwise have not been synthesized via the conventional technique. Although stable solid material with variable functionalities and intriguing structural motifs could be engineered by judicious selection of multivariate metal centers and multifunctional ligands. However, solid solution featuring mixed valence in MOCP is rare. Motivated by the ability of Pb2+ to adopt range of coordination numbers (CN) and chemical environments (CE), in addition to its …

Structure And Dynamics Of Phospholipid Vesicles And The Dependence On Nanoscale Interactions With Molecules Of Varying Complexity, Lakshapathy Widanelage Judith Upeka De Mel

LSU Doctoral Dissertations

In this dissertation, molecular interactions and changes imposed by nano-scale structures on phospholipid vesicles were investigated. 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC) large unilamellar vesicles (LUVs) were used as the model system. Understanding changes of the bilayer structure, interfacial properties, lipid dynamics, and self-assembly, allows bridging relationships between biological cell membrane structure and dynamics to cellular functionalities. For example, membrane curvature changes are linked to membrane protein functions, although the exact mechanisms of control are not yet understood. Moreover, the knowledge gained from vesicle models allows exploring novel strategies for drug delivery applications. To achieve this, DOPC LUVs were synthesized and characterized by a …

Potential Application Of Ionic Liquids For Electrodeposition Of The Material Targets For Production Of Diagnostic Radioisotopes, Maciej Chotkowski, Damian Połomski, Kenneth Czerwinski

Chemistry and Biochemistry Faculty Research

An overview of the reported electrochemistry studies on the chemistry of the element for targets for isotope production in ionic liquids (ILs) is provided. The majority of investigations have been dedicated to two aspects of the reactive element chemistry. The first part of this review presents description of the cyclotron targets properties, especially physicochemical characterization of irradiated elements. The second part is devoted to description of the electrodeposition procedures leading to obtain elements or their alloys coatings (e.g., nickel, uranium) as the targets for cyclotron and reactor generation of the radioisotopes. This review provides an evaluation of the role ILs …

Adsorption And Reconfiguration Of Amphiphiles At Silica-Water Interfaces: Role Of Electrostatic Interactions, Van Der Waals Forces And Hydrogen Bonds, Yao Wu

LSU Doctoral Dissertations

The ability to explore and predict metastable structures of hybrid self-assemblies is of central importance for the next generation of advanced materials with novel properties. As compared to their thermodynamically stable forms, the kinetically stabilized materials show improved functionality potentially over their stable counterparts. The self-assembly processes usually originate from weak intermolecular interactions, involving a dynamic competition between attractive and repulsive interactions. These weak forces, including van der Waals (vdW), electrostatic interaction and the hydrogen bonding (H-bonding), can be tuned by external stimuli, e.g., confinement, temperature and ionization, and consequently driving hybrid materials into different configurations. It is challenging to …

Topology And Control Of Self-Assembled Domain Patterns In Low-Dimensional Ferroelectrics, Y. Nahas, S. Prohorenko, Q. Zhang, V. Govinden, N. Valanoor, L. Bellaiche

Physics Faculty Publications and Presentations

Whilst often discussed as non-trivial phases of low-dimensional ferroelectrics, modulated polar phases such as the dipolar maze and the nano-bubble state have been appraised as essentially distinct. Here we emphasize their topological nature and show that these self-patterned polar states, but also additional mesophases such as the disconnected labyrinthine phase and the mixed bimeron-skyrmion phase, can be fathomed in their plurality through the unifying canvas of phase separation kinetics. Under compressive strain, varying the control parameter, i.e., the external electric field, conditions the nonequilibrium self-assembly of domains, and bridges nucleation and spinodal decomposition via the sequential onset of topological transitions. …

Research Progress Of Sulfur Cathode Catalytic Conversions For Lithium-Sulfur Batteries, Qin-Jun Shao, Jian Chen

Journal of Electrochemistry

The electrochemical reduction of sulfur (S) takes place through multistep reactions when S is used as a cathode material. The complete discharge of S to form final product lithium sulfide (Li₂S) is a two-electron reaction. The formation of low-order lithium polysulfides (LiPS) needs to overcome certain energy barriers. And the reduction of Li₂S₂ to Li₂S is the rate-limited step. The reaction kinetic of sulfur cathode is the critical key to determine the electrochemical performance of Li-S batteries, such as specific energy, specific power and low temperature performance, etc. Accelerating the rate-limited step kinetics …

A Model For The Anodic Carbonization Of Alkaline Polymer Electrolyte Fuel Cells, Qi-Hao Li, Ying-Ming Wang, Hua-Long Ma, Li Xiao, Gong-Wei Wang, Jun-Tao Lu, Lin Zhuang

Journal of Electrochemistry

The alkaline polymer electrolyte fuel cell (APEFC) has made appreciable progress in recent years but is still suffering performance loss during discharge with air as the oxidant. Several theories have been suggested to interpret the loss. However, efforts are still needed to reach a clear quantitative understanding. Based on the major experimental findings in combination with thermodynamics and kinetics of the reactions involved in the anode, this paper presents a model featuring layered carbonization in the anode and relevant grouped equations. The simulation results generated from the latter are compared with experiments, and possible principles to suppress the performance loss …

Porous-Electrode Theory Of Lithium Ion Battery: Old Paradigm And New Challenge, Xiao-Xiao Wang, Zi-Rui Zhou, Qiang Shan, Zeng-Ming Zhang, Jun Huang, Yu-Wen Liu, Sheng-Li Chen

Journal of Electrochemistry

A critical review on the porous electrode theory developed by Newman and his colleagues is presented. We propose several ideas for further development of this theory by analyzing its limitations. The classical Newman theory does not consider ion steric effect in describing ion transport in electrolyte solutions, which can be amended by a newly developed ion-vacancy coupled charge transfer model for ion transport in concentrated solutions. Ion transport in solid particles of active materials is essentially an ion-electron coupled transport process, and its rationality is verified by comparing the calculated and experimental diffusion coefficients of Li ⁺ ion in intercalation …

Highly Efficient Co2 Utilization Via Molten Salt Co2 Capture And Electrochemical Transformation Technology, Bo-Wen Deng, Hua-Yi Yin, Di-Hua Wang

Journal of Electrochemistry

The molten electrolytes exhibit high CO₂ absorption capacities, wide electrochemical windows and excellent reaction kinetics, which are promising electrolyte candidates for efficient capture and electrochemical conversion of high-flux CO₂ driven by renewable and clean electricity sources. This short review introduces the recent advancements of CO₂ electroreduction achieved by the authors using molten salt CO₂ capture and electrochemical transformation (MSCC-ET) technology, involving CO₂ absorption kinetics, cathodic kinetics, controllable synthesis of carbon products with unique nanostructures, development of inert oxygen evolution anodes and CO₂ conversion efficiency as well as energy efficiency. The challenges and prospects are …

Facile Synthesis Of Nitrogen-Doped Graphene-Like Active Carbon Materials For High Performance Lithium-Sulfur Battery, Quan-Hua Meng, Wen-Wen Deng, Chang-Ming Li

Journal of Electrochemistry

Lithium-sulphur (Li-S) battery is regarded as a promising energy storage device because of its high theoretical capacity. However, the low S utilization and short cycling life limit the commercial applications. In this work, nitrogen-doped graphene-like carbon (NGC) materials were synthesized by simply pyrolyzing and carbonizing the mixture of melamine (C₃H₆N₆) and L-cysteine (C₃H₇NO₂S). The graphene-like structure in NGC effectively buffered the volume change of S during the discharge/charge process and improved the cycling stability. Meanwhile, nitrogen-containing functional groups in NGC facilitated the transportation of ions and suppressed the …

Research Progress Of Key Components In Lithium-Sulfur Batteries, Jia-Jia Chen, Quan-Feng Dong

Journal of Electrochemistry

Due to the much higher theoretical specific capacity and energy density than the ones of traditional lithium ion battery, Li-S batteries have long been at the pinnacle in the realms of high-energy Li-metal batteries. However, the complicated electrochemical reactions on the sulfur cathode and Li anode, induced by the thermodynamic and kinetic behaviors of lithium polysulfides, are the intrinsic bottleneck to realize the full potential of Li-S batteries for practical application. In this review, we firstly discuss the roles, and thermodynamic and kinetic behaviors of polysulfides in the charging and discharging processes of Li-S batteries. Then, the functional design and …