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Articles 1 - 8 of 8
Full-Text Articles in Physical Sciences and Mathematics
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 …
Self-Assembly Mechanisms Of Organosilanes And Porphyrins Investigated With Scanning Probe Microscopy, Phillip Charles Chambers Ii
Self-Assembly Mechanisms Of Organosilanes And Porphyrins Investigated With Scanning Probe Microscopy, Phillip Charles Chambers Ii
LSU Doctoral Dissertations
This dissertation details the development of new fabrication strategies for the preparation of spatially selective surfaces by combining techniques of particle lithography and scanning probe microscopy (SPM). This combination of lithography and nanoscale surface characterization was applied to study the mechanisms of molecular level surface-assembly of organosilanes and porphyrin on surfaces of Si(111). Particle lithography was used to investigate the surface assembly of 4-chloromethylphenyltrichlorosilane (CMPS) within exposed sites of nanoholes in selected solvents and at selected temperatures to gain insight into the details of self-polymerization. Nanopillars of CMPS were generated under selected conditions of solvent and temperature and characterized with …
Scanning Probe Investigations Of Multidentate Thiol And Spatially Confined Porphyrin Nanoassemblies Using Nanoscale Lithography, Xianglin Zhai Zhai
Scanning Probe Investigations Of Multidentate Thiol And Spatially Confined Porphyrin Nanoassemblies Using Nanoscale Lithography, Xianglin Zhai Zhai
LSU Doctoral Dissertations
Approaches to prepare spatially selective surfaces were developed in this dissertation for constructing nanopatterns of organic thin film materials. Nanoscale surface patterns were prepared using immersion particle lithography and scanning probe lithography combined with organothiol chemistry. Organic thin films and nanomaterials can be patterned with tunable periodicities and designed shapes by selecting the diameter of mesospheres used as surface masks or scanning probe lithography, respectively. The surface platforms of well-defined nanopatterns are ideal for high resolution investigations using scanning probe microscopy (SPM). Local measurements of surface properties and conductive properties combined with nanolithography were accomplished at the molecular level. Sample …
Scanning Probe Investigations Of The Surface Self-Assembly Of Organothiols And Organosilanes Using Nanoscale Lithography, Tian Tian
LSU Doctoral Dissertations
Particle lithography and scanning probe lithography were applied to study the kinetics and mechanisms of surface self-assembly processes. Organothiols on Au(111) and organosilane on Si(111) were chosen as model systems for investigations at the nanoscale using atomic force microscopy (AFM). Fundamental insight of structure/property interrelationships and understanding the properties of novel materials are critical for developments with molecular devices. Methods using an AFM probe for nanofabrication have been applied successfully to prepare sophisticated molecular architectures with high reproducibility and spatial precision. The established capabilities of AFM-based nanografting were reviewed for inscribing patterns of diverse composition, to generate complicated surface designs …
Synthesis, Characterization, And Self-Assembly Of Porphyrins Conjugated To Superparamagnetic Colloidal Particles For Enhanced Photodynamic Therapy, Javoris Hollingsworth
Synthesis, Characterization, And Self-Assembly Of Porphyrins Conjugated To Superparamagnetic Colloidal Particles For Enhanced Photodynamic Therapy, Javoris Hollingsworth
LSU Doctoral Dissertations
Porphyrins and their derivatives are often used as photosensitizers in photodynamic therapy (PDT), which is a noninvasive antitumor treatment. The photochemical process for PDT involves exciting a photosensitizing agent with visible light, which induces cytotoxicity in the presence of oxygen as a result of forming reactive oxygen species (ROS). The ROS are the responsible components for invoking cell death and destruction of tumors. Although this mechanism is an effective cancer therapeutic, it still has many shortcomings. One major challenge of PDT concerns improving the tumor selectivity and specificity of photosensitizers because porphyrins have nonspecific affinity to tumor cells. The discussed …
Investigations Of Structure / Property Interrelationships Of Organic Thin Films Using Scanning Probe Microscopy And Nanolithography, Zorabel Mallorca Lejeune
Investigations Of Structure / Property Interrelationships Of Organic Thin Films Using Scanning Probe Microscopy And Nanolithography, Zorabel Mallorca Lejeune
LSU Doctoral Dissertations
Studies of the surface assembly and molecular organization of organic thin films were studied using scanning probe microscopy (SPM) and scanning probe lithography (SPL). Systems of organic thin films such as n-alkanethiols and pyridyl functionalized porphyrins were characterized at the molecular level, and measurements of the conductive properties of polythiophenes containing in-chain cobaltabisdicarbollides were accomplished. Understanding the self-organization and mechanisms of self-assembly of organic molecules provides fundamental insight for structure/property interrelationships. Investigations of the surface assembly of 5,10-diphenyl-15,20-di-pyridin-4-yl-porphyrin (DPP) on Au(111) were done using SPL methods of nanoshaving and nanografting. Automated computer designs were developed for nanofabrication to provide local …
Investigation Of Phospholipid Tubule Morphology For Use In Drug Delivery, Colleen Colson Garrett
Investigation Of Phospholipid Tubule Morphology For Use In Drug Delivery, Colleen Colson Garrett
LSU Doctoral Dissertations
Spherical vesicles consisting of phosphatidylcholines in which diacetylene groups have been inserted in the hydrocarbon tail centers give rise to hollow cylindrical tubes, known as “tubules”. The study of tubules has become an area of intense interest in recent years due to their unusual morphology, which raises several profound theoretical issues and suggests their use in a variety of applications. Tubule hollowness suggests medical and industrial encapsulations as well as filtration and purification applications. These potential uses, e.g., for drug and gene delivery, requires optimization of their morphology for the application. Tubules have many technologically desirable properties, such as a …
Self-Assembly And Its Inhibition In Bolaform Amphiphilic Dendrimers, Jirun Sun
Self-Assembly And Its Inhibition In Bolaform Amphiphilic Dendrimers, Jirun Sun
LSU Doctoral Dissertations
Self-assembly is scientifically interesting, technologically important, and sometimes life-threatening. A striking example: Alzheimer’s disease is caused by the self-assembly of the â-amyloid fragment of amyloid precursor protein. Such natural amphiphiles normally are very expensive and complicated to isolate. Synthetic mimics that are much cheaper and easier to prepare can facilitate the development of efficient characterization methods, even as they suggest new materials science applications. Two-directional arborols are synthetic bolaform amphiphilic dendrimers. They dissolve in hot water and form reversible gels at room temperature. Bundles of fibrils, which are made by self-assembly of arborols, are found in the gels. The properties …