Materials Chemistry Commons^™

Design Rules For The Nucleation, Growth, And Encapsulation Of Gold Nanoparticles With Applications To Cancer Imaging, Matthew A. Wall

Dissertations, Theses, and Capstone Projects

Surface-enhanced Raman scattering (SERS) nanoparticles are exciting candidates for high-precision cancer imaging due to their highly specific spectral signature (Raman “fingerprint”) and propensity for passive targeting of cancerous tissues. However, the signal intensity of currently available SERS nanoparticles is insufficient for cancer imaging via passive targeting in most solid tumors. The overarching aim of this body of work is to develop a new generation of SERS nanoparticles with sufficiently low limits of detection to enable robust detection of various solid tumors in vivo.

The complexity of SERS nanoparticles requires significant advances to the theoretical and experimental understanding of metal …

Ultrafast Spectroscopy And Energy Transfer In An Organic/Inorganic Composite Of Zinc Oxide And Graphite Oxide, Jeff A. Secor

Dissertations, Theses, and Capstone Projects

The energy transfers and nature of defect levels of an organic/inorganic composite of Zinc Oxide and Graphite are studied with multidimensional spectroscopy. The edge and surface states of each composite are uncovered using excitation emission experiments showing which defect states are mediating the energy transfer from the metal oxide to the graphite oxide. Multidimensional time resolved spectroscopy further describes the effect of the carbon phase on the energy transfer pathways in the material.

Probing The Transport Properties Of Chemically-Doped Single-Walled Carbon Nantotube Polymer Composites, Tammy Pheuphong, Tamara El-Hayek, Jeffrey Blackburn, Andrew Ferguson

STAR Program Research Presentations

Thermoelectric (TE) materials are used to convert waste heat into electrical power. Semiconducting single-walled carbon nanotubes (s-SWCNT) have great potential to be used in thermoelectric devices, either on their own or in composites with conducting polymers. Certain polymers can selectively extract s-SWCNT from raw carbon nanotube soot (containing impurities such as metallic SWCNT, amorphous carbon, metal catalysts particles), but most of these polymers (e.g. polyfluorenes) are electrical insulators, rendering them inefficient in TE nanocomposites. On the other hand, conducting polymers, such as poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), have been used in efficient TE nanocomposites, but have never been rationally designed with …

Effect Of Spalled Particles Thermal Degradation On A Hypersonic Flow Field Environment, Raghava S. C. Davuluri, Huaibao Zhang, Alexandre Martin

Mechanical Engineering Faculty Publications

Two-way coupling is performed between a spallation code and a hypersonic aerothermodynamics CFD solver to evaluate the effect of spalled particles on the flow field. Time accurate solutions are computed in argon and air flow fields. A single particle simulations and multiple particles simulations are performed and studied. The results show that the carbon vapor released by spalled particles tend to change the composition of the flow field, particularly the upstream region of the shock.

Effects Of Surface Coatings On Crystalization Of Calcium Sulfate, Shawn Pj Kirby, Josiah Reams, Kamran Ghiassi, Jeffrey Alston

STAR Program Research Presentations

Deposits from hard water can be problematic as they can form scaling on boilers and cooling towers. Scaling can reduce thermal efficiency. Coatings can be used to prevent mineral fouling by changing the surface energy. Some deposits have inverse solubility; such as calcium sulfate. This means that as temperature rises, they become less soluble and can crystallize out of solution. Calcium sulfate is often found in hard water. Crystalization tests were done to determine how coatings such as various POSS (Polyhedral oligomeric silsesquioxane) compounds acted as nucleating surfaces for calcium sulfate. POSS compounds were tested in particular because they …

Syntheses And Characterization Of [4]Ferrocenophane, Ahmed Sabah Al-Doori

Theses, Dissertations and Capstones

Metallocenophanes are metallocenes in which the cyclopentadienyl ligands are connected by a molecular bridge. Recently, metallocenophanes have received increasing attention because of their structure, chemical reactivity, and potential use as building blocks for new materials. Even though metallocenophanes have been synthesized by different methods, the majority of these methods involved the use of iron with rare examples of other metals. Therefore, a new method was employed that in addition to making ferrocenophane, will allow us to synthesize metallocenophanes with V, Cr, Mn, Co, and Ni as central metals. This thesis reports the synthesis of [4]ferrocenophane via a “flytrap” route. The …

Unraveling A Generic Growth Pattern In Structure Evolution Of Thiolate-Protected Gold Nanoclusters, Wen Wu Xu, Yadong Li, Yi Gao, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Precise control of the growth of thiolate-protected gold nanoclusters is a prerequisite for their applications in catalysis and bioengineering. Here, we bring to bear a new series of thiolateprotected nanoclusters with a unique growth pattern, i.e., Au₂₀(SR)₁₆, Au₂₈(SR)₂₀, Au₃₆(SR)₂₄, Au₄₄(SR)₂₈, and Au₅₂(SR)₃₂. These nanoclusters can be viewed as resulting from the stepwise addition of a common structural motif [Au₈(SR)₄]. The highly negative values of the nucleus-independent chemical shift (NICS) in the center of the tetrahedral Au4 …

Unraveling A Generic Growth Pattern In Structure Evolution Of Thiolate-Protected Gold Nanoclusters, Wen Wu Xu, Yadong Li, Yi Gao, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

Precise control of the growth of thiolate-protected gold nanoclusters is a prerequisite for their applications in catalysis and bioengineering. Here, we bring to bear a new series of thiolateprotected nanoclusters with a unique growth pattern, i.e., Au₂₀(SR)₁₆, Au₂₈(SR)₂₀, Au₃₆(SR)₂₄, Au₄₄(SR)₂₈, and Au₅₂(SR)₃₂. These nanoclusters can be viewed as resulting from the stepwise addition of a common structural motif [Au₈(SR)₄]. The highly negative values of the nucleus-independent chemical shift (NICS) in the center of the tetrahedral Au …

Mechanistic Study Of Pressure And Temperature Dependent Structural Changes In Reactive Formation Of Silicon Carbonate, Bingyan Qu, Dongdong Li, Lei Wang, Jili Wu, Rulong Zhou, Bo Zhang, Xiao Cheng Zeng

Xiao Cheng Zeng Publications

The discovery of the silicon carbonate through chemical reaction between porous SiO₂ and gaseous CO₂ addressed a long-standing question regarding whether the reaction between CO₂ and SiO₂ is possible. However, the detailed atomic structure of silicon carbonate and associated reaction mechanism are still largely unknown. We explore structure changes of silicon carbonate with pressure and temperature based on systematic ab initio molecular dynamics simulations. Our simulations suggest that the reaction proceeds at the surface of the porous SiO₂. Increasing number of CO₂ molecules can take part in the reaction by increasing either the …

Surprising Impact Of Remote Groups On The Folding–Unfolding And Dimer-Chain Equilibria Of Bifunctional H-Bonding Unimers, Rui Liu, Shuang Cheng, Erin S. Baker, Richard D. Smith, Xiao Cheng Zeng, Rui Liu

Xiao Cheng Zeng Publications

Oligoamide 1, consisting of two H-bonding units linked by a trimethylene linker, was previously found to form a very stable, folded dimer. In this work, replacing the side chains and end groups of 1 led to derivatives that show the surprising impact of end groups on the folding and dimer-chain equilibria of the resultant molecules.

Improved High Temperature Stability Of Anatase Tio2 Photocatalysts By N, F, P Co-Doping, Rachel Fagan, Declan Mccormack, Steven Hinder, Suresh Pillai

Articles

Among the three commonly occurring phases (anatase, rutile, and brookite) of TiO2, the anatase form is reported to be the best photocatalyst due to the improved charge-carrier mobility and the greater number of surface hydroxyl groups. The anatase to rutile transition in titania photocatalysts usually occurs at a temperature between 500 °C to 700 °C. Development of a high temperature stable (above 1000 °C) anatase phase is important for various environmental applications (e.g. self-cleaning ceramic tiles, anti-microbial sanitary wares, etc.). In this study, the use of ammonium hexafluorophosphate as a single source dopant (method A) and urea, trifluoroacetic acid and …

Optimisation Of Anodic Oxidation Of Aluminium For Enhanced Adhesion And Corrosion Properties Of Sol-Gel Coatings., Michael Whelan, Tobin Edmond, John Cassidy, John Colreavy, Brendan Duffy

Articles

The anodising process for clad and bare AA2024-T3 has been optimised as a surface preparation technique prior to sol-gel coating deposition. The combination of anodised aluminium surfaces and organically functionalised sol-gel chemistry have been investigated to impart elevated corrosion resistance and increased mechanical properties to the aluminium metal. A duplex anodising process has been developed to utilise the natural corrosion resistance properties of sulphuric acid anodising with the adhesion and hosting properties of phosphoric acid anodising. The novel anodising process and sol-gel sealed surfaces have been characterised using field emission scanning electron microscopy, energy dispersive x-ray spectroscopy. Performance of the …

Mechanistic Studies Of The Structure-Photostability Relationship Of Organic Conjugated Polymers, Logan Paul Sanow

Electronic Theses and Dissertations

Organic Conjugated polymers (CPs) are a subject of intense research for their application in organic photovoltaics (OPVs), organic light emitting diodes (OLEDs), solid-state dye lasing, biological imaging and sensing, chemical sensing and remote sensing. CPs are key materials in the quest for more sustainable forms of renewable energy, making electronics more versatile and light weight, and increasing the functionality of everyday materials. For these applications and others that use CPs as the photoactive material, one of their main drawbacks is their susceptibility to photodegradation. Photodegradation occurs when the material is exposed to light leading to irreversible changes in the materials, …

Artscience, Dustin Swiers

All Graduate Theses, Dissertations, and Other Capstone Projects

My thesis show opened on Friday, March 11, 2016 at the 410 project's art gallery, located in downtown Mankato.

The artwork consisted of sculptures displayed on pedestals, hanging on the walls, sitting on specifically constructed arrangements, and hanging from the ceiling. The materials I used to create these sculptures have a dramatically contrasting appearance, but have one universal similarity. At some point most of the materials used were liquid or fluid. I used metals, ceramics, hand blown glass, plastics, and wax. I like to work with these materials in that fluid state because of the added flexibility and forgiveness they …

Characterization Of Biochars Produced From Peanut Hulls And Pine Wood With Different Pyrolysis Conditions, James W. Lee, Bob Hawkins, Michelle K. Kidder, Barbara R. Evans, A. C. Buchanan, Danny Day

Chemistry & Biochemistry Faculty Publications

Background

Application of modern biomass pyrolysis methods for production of biofuels and biochar is potentially a significant approach to enable global carbon capture and sequestration. To realize this potential, it is essential to develop methods that produce biochar with the characteristics needed for effective soil amendment.

Methods

Biochar materials were produced from peanut hulls and pine wood with different pyrolysis conditions, then characterized by cation exchange (CEC) capacity assays, nitrogen adsorption–desorption isotherm measurements, micro/nanostructural imaging, infrared spectra and elemental analyses.

Results

Under a standard assay condition of pH 8.5, the CEC values of the peanut hull-derived biochar materials, ranging from …

Effect Of Synthesis On Quality, Electronic Properties And Environmental Stability Of Individual Monolayer Ti3C2 Mxene Flakes, Alexey Lipatov, Mohamed H. Alhabeb, Maria R. Lukatskaya, Alex J. Boson, Yury Gogotsi, Alexander Sinitskii

Department of Chemistry: Faculty Publications

2D transition metal carbide Ti₃C₂T_x (T stands for surface termination), the most widely studied MXene, has shown outstanding electrochemical properties and promise for a number of bulk applications. However, electronic properties of individual MXene flakes, which are important for understanding the potential of these materials, remain largely unexplored. Herein, a modified synthetic method is reported for producing high-quality monolayer Ti₃C₂T_x flakes. Field-effect transistors (FETs) based on monolayer Ti₃C₂T_x flakes are fabricated and their electronic properties are measured. Individual Ti₃C₂T_x flakes …

Dynamic Atomistic Study Of Tunnel Functions In Nanostructured Transitional Metal Oxides, Yifei Yuan

Dissertations, Master's Theses and Master's Reports

Alpha (α-) MnO₂ is a well know transitional metal oxide possessing one dimensional 2×2 (4.6 × 4.6 Ų) tunnels for accommodation of various ions. Such a characteristic tunneled structure has enabled the wide applications of α-MnO₂ in the fields of ion exchange, molecular sieves, biosensor, catalysis and energy storage. This PhD dissertation focuses on the dynamic study of ion transport functionality of α-MnO₂ at atomic level using an aberration corrected scanning transmission electron microscopy equipped with a special holder with a scanning tunneling microscopy probe.

The wide application of in situ TEM studying the dynamic …

Electrochemical Oxidation To Construct A Nickel Sulfide/Oxide Heterostructure With Improvement Of Capacitance, Xuan Liu, Bo You, Xin-Yao Yu, Jeffrey Chipman, Yujie Sun

Chemistry and Biochemistry Faculty Publications

Supercapacitors have been widely recognized as a promising device for the storage of renewable energy. Herein, a facile electrochemical oxidation strategy is described to construct a nickel sulfide/oxide heterostructure which enhances the specific areal capacitance of Ni₃S₂ electrode (2035 mF cm^-2 vs. 31 mF cm^-2 at a current density of 8 mA cm^-2), while still maintaining great stability, showing no performance degradation after 5000 charge-discharge cycles. Its exceptional capacitance, advanced rate capability, and superior cycling stability are attributed to the transformed composition and unique nanostructure achieved during electrochemical oxidation, which can provide a …

Analysis Of An Adhesion Promoter For Rubber To Metal Bonding, Killian Barton

Doctoral

The intermolecular and intramolecular changes induced by thermal stress in an industrial rubber to metal coupling agent (the ‘green molecule’ or GM) are the subject of this thesis. The GM was analysed in-situ in a model application environment using vibrational spectroscopy. NMR spectroscopy was used in order to analyse the solution chemistry of the compound and how this changed as a result of thermal stress. The interaction of the GM and the substrate was analysed using a range of surface analysis techniques including XPS, AFMIR and EDX. An example of a complex substrate, the zinc phosphate conversion coating, was analysed …

Two-Dimensional Interlocked Pentagonal Bilayer Ice: How Do Water Molecules Form A Hydrogen Bonding Network?, Weiduo Zhu, Wen- Hui Zhao, Lu Wang, Di Yin, Min Jia, Jinlong Yang, Xiao Cheng Zeng, Lan-Feng Yuan

Xiao Cheng Zeng Publications

The plethora of ice structures observed both in bulk and under nanoscale confinement reflects the extraordinary ability of water molecules to form diverse forms of hydrogen bonding networks. An ideal hydrogen bonding network of water should satisfy three requirements: (1) four hydrogen bonds connected with every water molecule, (2) nearly linear hydrogen bonds, and (3) tetrahedral configuration for the four hydrogen bonds around an O atom. However, under nanoscale confinement, some of the three requirements have to be unmet, and the selection of the specific requirement(s) leads to different types of hydrogen bonding structures. According to molecular dynamics (MD) simulations …