Physical Sciences and Mathematics Commons^™

Poly(Ionic Liquid)S For Magnetic, Ionic, And Electrical Stimuli-Responsive Applications, Kayla Ann Foley

Graduate Theses and Dissertations

Poly(ionic liquid)s (PILs) are a fascinating subclass of strong polyelectrolytes formed from polymerizable ionic liquids. As a result of their unique properties and counterion exchangeability, PILs can exhibit conformation structure or material property changes in response to external stimuli such as changes in pH/ionic environment, magnetic fields, and electric potentials. In Chapter 1, a comprehensive review of PILs design as well as their stimuli-responsive behavior is provided. Additional motivation for each dissertation chapter is also discussed. In Chapter 2, magnetically responsive PILs (MPILs) are developed from complexing paramagnetic salts with a random PIL copolymer containing a metal-coordinating co-monomer, acrylamide. A …

Architecture Of Heptagonal Metallo-Macrocycles Via Embedding Metal Nodes Into Its Rigid Backbone, A.M.Shashika D. Wijerathna, He Zhao, Qiangqiang Dong, Qixia Bai, Zhiyuan Jiang, Jie Yuan, Jun Wang, Mingzhao Chen, Markus Zirnheld, Rockwell T. Li, Yuan Zhang, Yiming Li, Pingshan Wang

College of Sciences Posters

Metal-organic macrocycles have received increasing attention not only due to their versatile applications such as molecular recognition, compounds encapsulation, anti-bacteria and others, but also for their important role in the study of structure-property relationship at nano scale. However, most of the constructions utilize benzene ring as the backbone, which restricts the ligand arm angle in the range of 60, 120 and 180 degrees. Thus, the topologies of most metallo-macrocycles are limited as triangles and hexagons, and explorations of using other backbones with large angles and the construction of metallo-macrocycles with more than six edges are very rare.

In this study, …

Para-Methoxybenzylidene Acetal-Protected D-Glucosamine Derivatives As Ph-Responsive Gelators And Their Applications For Drug Delivery, Jonathan Bietsch, Logan Baker, Anna Duffney, Alice Mao, Mary Foutz, Cheandri Ackermann, Guijun Wang

Chemistry & Biochemistry Faculty Publications

Carbohydrate-based low molecular weight gelators (LMWGs) are compounds with the capability to self-assemble into complex molecular networks within a solvent, leading to solvent immobilization. This process of gel formation depends on noncovalent interactions, including Van der Waals, hydrogen bonding, and π–π stacking. Due to their potential applications in environmental remediation, drug delivery, and tissue engineering, these molecules have emerged as an important area of research. In particular, various 4,6-O-benzylidene acetal-protected D-glucosamine derivatives have shown promising gelation abilities. In this study, a series of C-2-carbamate derivatives containing a para-methoxy benzylidene acetal functional group were synthesized and characterized. These compounds exhibited good …

Visible Light Photocatalysis Of Organic Reactions In H2o, Sankarsan Biswas

Dissertations, Theses, and Capstone Projects

Visible-light photocatalysis in H₂O provides an attractive, green alternative to typical organic synthesis, which often involves toxic solvents, metal catalysts, and large energy demands. Hence, there is a growing need for an efficient photocatalytic methods that use either aqueous media as a solvent or can proceed solvent-free. However, commercially available photocatalysts do not work well for aqueous photocatalysis. Supramolecular systems in particular have been explored recently to address these issues associated with aqueous photocatalysis. Chapter 1 will review recent advances in aqueous supramolecular photocatalysis with examples of different supramolecular systems and how they have addressed some of the …

Development Of Stimuli-Responsive Liposomes For Drug Delivery Applications, Jinchao Lou

Doctoral Dissertations

Liposomes are spherical nano-assemblies that are proven to be effective drug delivery vehicles. Due to their unique bilayer structures, they are able to encapsulate both hydrophilic and hydrophobic drugs in their aqueous inner core and membrane bilayers, respectively. While liposomal delivery platforms exbibit numerous advantages, the therapeutic efficacy of these platforms would be enhanced by developing triggered release strategies such that one can tune the timing and location of the cargo release in a controlled manner. In this dissertation, we mainly present the development of stimuli-responsive liposomes targeting different disease-associated metabolites utilizing rationally designed synthetic lipid switches.

In Chapter 2, …

Synthesis, Fabrication, And Assembly Of Mesoscale Polymer Filaments, Dylan M. Barber

Doctoral Dissertations

Mesoscale materials, with feature sizes in the range of one hundred nanometers to tens of micrometers, are ubiquitous in Nature. In organisms, mesoscale building blocks connect the properties of underlying molecular and nanoscructures to those of macroscale, organism-scale materials through hierarchical assemblies of recurring structural motifs. The collective action of large numbers of mesoscale features can afford stunning features like the structural color of the morpho butterfly wing, calcium ion-mediated movement in muscle, and wood structures like xylem that can support enormous external compressive loads and negative internal pressure to transport nutrients throughout an organism. In synthetic systems, the design, …

Investigation Of Dna Hybridization In Localized Systems In Close Proximity, Ashley M. Sewsankar

Honors Undergraduate Theses

Hybridization of two or more DNA or RNA strands is well documented for the process taking place with all strands free in solution or when one strand is immobilized on a substrate. This study contributes to the investigation of the hybridization process when two single DNA strands (ssDNA) are in close proximity. We took advantage of an X sensor in which hybridization of four DNA strands enables the formation of a DNA four-way junction (crossover or X) structure. We immobilized multiple layers of crossover structures to study its hybridization being triggered by short ssDNA coming from solution and further investigate …

Self-Assembly Of Black Cumin Oil-Based Nanoemulsion On Various Surfactants: A Molecular Dynamics Study, Aulia Fikri Hidayat, Taufik Muhammad Fakih

Makara Journal of Science

Black cumin is commonly used as traditional medicine due to its wide range of pharmacological potential. Black cumin oil (BCO) was often prepared as nanoemulsion to improve its solubility, stability, and bioavailability. This study was conducted to investigate the molecular behavior as well as structural evolution of BCO-surfactant systems during self-assembly micellization using molecular dynamics (MD) simulations. Several BCO constituents and variations of surfactants were employed to model BCO-surfactant systems. 50 ns of MD simulations were performed to elucidate their evolution of structures and physicochemical properties during formation. Results showed that BCO-tween20 and BCO-lecithin were able to form spherical-shaped micelles …

Synthesis And Characterization Of 4,6-Protected Glucosamine Derivatives And Branched Glycoconjugates, Jonathan Bietsch

Chemistry & Biochemistry Theses & Dissertations

Low molecular weight gelators (LMWGs) are small molecules that self-assemble in appropriate solvents to form three dimensional networks that immobilize the solvent, creating a supramolecular gel. The self-assembly of LMWGs occurs through non-covalent interactions such as hydrogen bonding, aromatic interactions, donor-acceptor interactions, Van der Waals interactions, hydrophobic forces, halogen bonding, etc. Due to self-assembly occurring through reversible non-covalent interactions, supramolecular gels can undergo a gel to solution transformation. Because of this, these materials can be sensitive to external stimuli such as temperature changes, pH changes, and other stimuli that effect non-covalent interactions. This makes the synthesis of LMWG’s an appealing …

From Persistent Radicals To Conductivity: A Structure Property Investigation In A Series Of Urea-Tethered Halogenated Triphenylamines, Muhammad Saddam Hossain

Theses and Dissertations

Triphenylamines (TPAs) are known to form persistent organic radicals either by chemical, electrochemical or photoinduced oxidation. Typically, fully para-substituted TPAs form stable radical cations while the radical cations in partially substituted systems quickly degrade. Herein, we study the effects of solid-state organization on a series of urea tethered halogenated TPAs 1 (X = H, Cl, Br, I) and compare their radical cation formation and persistence after UV-irradiation. These halogenated urea tethered TPAs were examined by single-crystal X-ray diffraction where their assembly was guided by threecentered urea hydrogen bonding interaction. As expected, all compounds form photogenerated radical cations in solution, but …

Computational Investigation Of Nanoparticle Immersion And Selfassembly, Tara Allison Tyler Nitka

Open Access Theses & Dissertations

Both neutral and charged nanoparticles with a variety of compositions, shapes, and sizes have beenpreviously prepared. These nanoparticles have been demonstrated to self-assemble into a variety of superlattices and binary superlattices both in bulk solution and at surfaces of solutions, and the structures formed by self-assembly have been shown to depend on nanoparticle chemistry and charge as well as on whether assembly takes place at a surface or in bulk. Furthermore, the prepared isolated and self-assembled nanoparticles have a number of biomedical, nanotechnology, and industrial applications. In this Dissertation, I present my research on three general topics. First, I will …

Stimuli Responsive Dye-Containing Peg-Pla Block Copolymer Micelles And Computationally Assisted Design Of A Stapled Peptide Bundle, Tyler L. Odom

MSU Graduate Theses

In this thesis, I report the preparation and characterization of dye-containing PEG-b-PLA block copolymer micelles and the computational design of a novel coiled-coil peptide bundle. The PEG-b-PLA micelles encapsulate hydrophobic molecules into their core and have strong potential as nanocontainers or delivery vesicles. In theory, these internalized molecules can be released upon exposure to mechanical forces that disrupt the micellar structures. This force-responsive nature is one of the inherent properties of micellar systems. However, there is a stark lack of research that utilize this property in applications. Along those lines, I have studied the behavior of …

Structure Formation And Coupling Reactions Of Hexaphenylbenzene And Its Brominated Analog, Jacob D. Teeter, Paulo S. Costa, Christoph Dobner, Mamun Sarker, Alexander Sinitskii, A Enders

Chemistry Department: Faculty Publications

The on-surface coupling of the prototypical precursor molecule for graphene nanoribbon synthesis, 6,11-dibromo-1,2,3,4-tetraphenyltriphenylene (C₄₂Br₂H₂₆, TPTP), and its non-brominated analog hexaphenylbenzene (C₄₂H₃₀, HPB), was investigated on coinage metal substrates as a function of thermal treatment. For HPB, which forms non-covalent 2D monolayers at room temperature, a thermally induced transition of the monolayer’s structure could be achieved by moderate annealing, which is likely driven by π-bond formation. It is found that the dibrominated carbon positions of TPTP do not guide the coupling if the growth occurs on a substrate at temperatures that …

Synthesis And Self-Assembling Properties Of Peracetylated Β-1 Triazolyl Alkyl D Glucosides And D-Galactosides, Pooja Sharma, Anji Chen, Dan Wang, Guijun Wang

Chemistry & Biochemistry Faculty Publications

Carbohydrate-based low-molecular-weight gelators (LMWGs) are useful classes of compounds due to their numerous applications. Among sugar-based LMWGs, certain peracetylated sugar beta-triazole derivatives were found to be effective organogelators and showed interesting self-assembling properties. To further understand the structural influence towards molecular assemblies and obtain new functional materials with interesting properties, we designed and synthesized a library of tetraacetyl beta-1-triazolyl alkyl-D-glucosides and D-galactosides, in which a two or three carbon spacer is inserted between the anomeric position and the triazole moiety. A series of 16 glucose derivatives and 14 galactose derivatives were synthesized and analyzed. The self-assembling properties of these new …

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 …

Effect Of Vortex-Induced Physical Stress On Fluorescent Properties Of Dye-Containing Poly(Ethylene Glycol)-Block-Poly(Lactic Acid) Micelles, Tyler L. Odom, Jacob R. Blankenship, Giselle Campos, Devin C. Mart, Wenyan Liu, Risheng Wang, Keiichi Yoshimatsu

Chemistry Faculty Research & Creative Works

The effect of vortex-induced mechanical stresses on the fluorescent properties of dye-containing poly(ethylene glycol)-block-poly(lactic acid) (PEG-b-PLA) block copolymer micelles has been investigated. PEG-b-PLA block copolymer micelles containing fluorescent dyes, 3,3′-dioctadecyloxacarbocyanine perchlorate (DiO) and/or 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiI), are prepared by a simple one-step procedure that involves the self-assembly of block copolymers and spontaneous incorporation of hydrophobic dyes into the core of the micelles. Upon vortexing, the micelle dispersion samples showed a decrease in fluorescence intensity in a rotational speed- and time-dependent manner. The results demonstrated that the vortexing can alter the fluorescent properties of the dye-containing PEG-b-PLA block copolymer micelle dispersion …

Modulating Nanoparticle-Protein Interactions Through Covalent Or Noncovalent Approach For Biomedical Applications, Jingjing Gao

Doctoral Dissertations

Discoveries at the interface of chemistry, biology, and materials science have emerged as a powerful route to impact life science in this century. My research in the Thayumanavan group is focused on problems at this interface. A common theme of all the six projects is the use of modern synthetic organic chemistry to build interesting, novel macromolecules which are chemically rich, to study the molecular self-assembly behavior in solution and then translate to solve problems in the biomedical area. By addressing the design challenge to prepare novel amphiphiles with desired functional groups, controlled molecular weight and the ability to respond …

Gravity-Drawing Flexible Silicone Filaments As Fiber Optics And Model Foldamers, Katherine Snell

CMC Senior Theses

Here, we present a method of gravity-drawing polydimethylsiloxane (PDMS) silicone fibers with application as fiber optics and as model foldamers. Beginning as a viscous liquid, PDMS is cured using heat until its measured viscosity reaches 4000 mPa•s. The semi-cured elastomer is then extruded through a tube furnace to produce thin (diameters on the order of hundred micrometers) filaments with scalable lengths. PDMS is biocompatible, gas-permeable, flexible, and hydrophobic. Additionally, the PDMS surface hydrophobicity can be modified via UV exposure, O2 plasma, and corona discharge. We demonstrate the patternibility (i.e patterns of hydrophobicity) of PDMS fibers, adding complexity to potential foldamer …

Stimuli-Responsive Gelators From Carbamoyl Sugar Derivatives And Their Responses To Metal Ions And Tetrabutylammonium Salts, Dan Wang, Anji Chen, Joedian Morris, Guijun Wang

Chemistry & Biochemistry Faculty Publications

Carbohydrate-based low molecular weight gelators (LMWGs) are interesting compounds with a variety of applications. In this research, a library of nineteen carbamate derivatives of N-acetyl-D-glucosamine were synthesized and characterized, and several derivatives were found to be effective LMWGs. They formed gels in pump oils as well as mixtures of water with ethanol or water with DMSO. The structures of the carbamoyl chains played an important role in the gelation properties, short chain aliphatic derivatives and phenyl carbamates formed gels in more solvents than certain aromatic and dimeric carbamates. The phenyl carbamate gelator was also selected for the encapsulation of …

Construction Of G-Quadruplexes Via Self-Assembly: Enhanced Stability And Unique Properties, Ying He

USF Tampa Graduate Theses and Dissertations

This dissertation mainly contains three parts: 1) The construction of well-defined G8-octamers through the monomer conformational design. 2) The construction of cross-layer interactions in the G8-octamer for enhanced stability in H-bond competitive solvents. 3) Design and synthesis of 8-triazole guanosine with photoluminescent properties.

Through the structural conformational design, we have developed a new class of guanosine derivatives with modification on guanine (8-aryl) and ribose (2’,3’-isopropylidene). This unique design has led to the formation of the first discrete G8-octamer with structure characterized by NMR, MS and single crystal X-ray diffraction. The selectivity between monovalent (K+) and divalent cat-ions (Ba2+ and Sr2+) …

Definition Of The Chalcogen Bond (Iupac Recommendations 2019), Christer B. Aakeroy, David L. Bryce, Gautam R. Desiraju, Antonio Frontera, Anthony C. Legon, Francesco Nicotra, Kari Rissanen, Steve Scheiner, Giancarlo Terraneo, Pierangelo Metrangolo, Giuseppe Resnati

Chemistry and Biochemistry Faculty Publications

This recommendation proposes a definition for the term “chalcogen bond”; it is recommended the term is used to designate the specific subset of inter- and intramolecular interactions formed by chalcogen atoms wherein the Group 16 element is the electrophilic site.

Probing The Gelation Phenomena In Molecular And Seed-Based Gels, Malick Samateh

Dissertations, Theses, and Capstone Projects

The interest in molecular gels has been gaining momentum as evident from being developed for a broad spectrum of applications. This impetus stems from several reasons that include: (i) molecular gels are highly stimuli responsive as they easily respond to thermodynamic changes, disintegrating into well-defined chemicals/building blocks because of the purely physical (in contrast to chemically cross-linked) nature of the interactions holding their 3D networks together; (ii) the sheer abundance of simple small molecules to choose starting materials from and the vast potential of tunability of the low molecular weight gelators (LMWGs) make the LMWGs and the molecular gels highly …

Reactive And Stimuli-Responsive Sulfonium-Based Polymer Zwitterions, Cristiam Santa Chalarca

Doctoral Dissertations

This dissertation describes the synthesis and characterization of novel monomers and (co)polymer zwitterions that incorporate trialkylsulfonium cations. The novel materials presented herein constitute a unique type of polymer zwitterions that exhibit salt- and temperature-dependent water solubility as well as inherent reactivity. The behavior of these polymers in aqueous solutions, as nanostructures, and at liquid-liquid interfaces was studied; in all cases, the inherent reactivity of the polymers was harnessed towards the fabrication of novel polymers and soft materials. Following an introductory chapter, Chapter 2 describes the synthesis of sulfonium sulfonate monomers and polymer zwitterions. Both styrenic and methacrylic monomers were synthesized …

Peptide Mediated Co-Assembly Of Porphyrin: Towards Sustainable Biomaterials For Light Harvesting And Catalysis, Wsm Nadeesha K. Wijerathne

Dissertations, Theses, and Capstone Projects

The diverse molecular functions of naturally occurring biomaterials designed from proteins are fundamentally based on a set of conserved building blocks, namely the 20 gene coded amino acids. The supramolecular structures and functions of proteins dictates by the self-assembly, where the complexity of proteins arise from a large number of amino acids. Generation of biomimetic systems that resemble the structures and functions of proteins is of great interest yet challenging due to the tremendous complexity of the natural systems. It is important to investigate alternative strategies to design much simpler systems that exhibit the same or similar function as proteins. …

Synthesis Of Flower-Like Vanadium Disulfide For Lithium Storage Application, Pan Li, Jian Liu, Wei-Yi Sun, Hai-Xia Li, Zhan-Liang Tao

Journal of Electrochemistry

In order to improve the electrochemical properties of vanadium disulfide (VS₂) as an electrode material in Li-ion battery, the flower-like VS₂ was prepared by a one-step hydrothermal method with the addition of polyethylene glycol 400. The phase and morphology of the product were characterized by using X-ray diffraction and field emission scanning electron microscopy. During the growth process, it was observed that the flower-like VS₂ was interspersed with several hexagonal vanadium disulfide nanosheets, which had a high specific surface area and excellent structural stability. The flower-like VS₂ was used for the cathode material test in …

Multi-Stimuli-Responsive Self-Immolative Polymer Assemblies, Rebecca E. Yardley, Elizabeth R. Gillies

Chemistry Publications

Self-immolative polymers (SIPs) undergo depolymerization in response to the cleavage of stimuli-responsive end-caps from their termini. Some classes of SIPs, including polycarbamates, have depolymerization rates that depend on environmental factors such as solvent and pH. In previous work, hydrophobic SIPs have been incorporated into amphiphilic block copolymers and used to prepare nanoassemblies. However, stimuli-responsive hydrophilic blocks have not previously been incorporated. In the current work, we synthesized amphiphilic copolymers composed of a hydrophobic polycarbamate SIP block and a hydrophilic poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) block connected by a UV light-responsive linker end-cap. It was hypothesized that after assembly of the block copolymers …

Synthesis And Characterization Of Fluorescent Nanojars, Vageesha Warnajith Liyana Gunawardana

Masters Theses

Self-assembly is a powerful tool utilized by synthetic chemists to create large, intricate structures for a variety of applications such as drug delivery, adaptable materials and electronics. In contrast to stepwise synthesis, this process allows the formation of intricate molecular architectures starting from synthetically rudimentary building blocks. Nanojars are class of self-assembling, cyclic copper(II) pyrazolate coordination compounds that encapsulate oxoanions with negative two or three charge. The strong anion binding characteristics of nanojars have potential towards developing novel tools for detecting biologically and environmentally relevant anions such as carbonate, sulfate and phosphate.

This work addresses the design and synthesis of …

Study Of Self-Assembly And Stimuli Responsive Behavior In Polymeric And Dendritic Amphiphiles, Poornima Rangadurai

Doctoral Dissertations

Natural processes are intricately detailed and able to convert molecular-level events into macroscopic or visually observable properties. This is made possible through multiple interactions at the molecular level, signaling due to covalent and non-covalent interactions, and supramolecular networks that rely on dynamic, non-equilibrium structures. Detailing processes in this manner is the current quest for material science research and designing materials for this purpose is usually via a key process known as self-assembly. Self-assembly is a process in which a material with varied components organizes itself into a particular pattern due to various specific inter and intra molecular interactions. By understanding …

The Design And Synthesis Of A Photo-Controlled, Peptide-Based Potential Drug Carrier, Melek Parlak Khali̇ly, Sali̇h Özçubukçu

Turkish Journal of Chemistry

Our focus in this study is on the design and synthesis of a light-responsive peptide-based nanocarrier in order to develop effective and biocompatible drug delivery systems. The synthesized nanocarrier is basically composed of peptide amphiphiles comprising a micelle forming a Pro-Pro-Pro-Lys-Lys-Lys peptide sequence with an attached anthracene fluorophore. Anthracene containing an inner core of the micelle can serve as a storage site for poorly water-soluble drugs. Moreover, anthracenes that come in close proximity with the formation of micellar structures can undergo photodimerization upon irradiation at 365 nm, which disrupts the micelle structures formed by the self-assembly of the peptide amphiphiles. …

Synthesis And Characterization Of Glycolipids, Glycoclusters And Glycomacrocycles, Anji Chen

Chemistry & Biochemistry Theses & Dissertations

Low molecular-weight gelators (LMWGs) are a fascinating and interesting class of compounds that can self-assemble and form supramolecular structures in appropriate solvents. The gelators form fibrous networks which entrap the solvent and result in a supramolecular gel. Carbohydrate-derived LMWGs are especially useful since they are more likely to be biocompatible and biodegradable. Dendritic gelators are branch-shaped molecules with precise molecular weight that are between small molecules and polymer gelators. Glycoclusters with sugar moieties at the periphery of the molecules are important classes of bioactive compounds due to the multivalency effect. Lower generation glycoclusters are relatively small branched systems that have …