Engineering Commons^™

Macroscopic Patterning Via Dynamic Self-Assembly And Wrinkling Instability, Hyun Suk Kim

Open Access Dissertations

My PhD work focuses on developing new methods to create the macroscopic patterns in a simple, robust, and versatile way. For macroscopic pattern formation, we first use flow coating as an assembly technique, uniquely balancing two driving forces: (i) evaporative deposition of nonvolatile solutes at a three-phase contact line and (ii) precision movement of a confined meniscus layer. This balance leads to the formation of line-based patterns that range in height and width from nanometers to microns, with lengths greater than centimeters. Moreover, we couple this deposition methodology with functional ligand chemistry on the nanoparticle surface, which allows us to …

Porous Metal Oxide Materials Through Novel Fabrication Procedures, Nicholas Hendricks

Open Access Dissertations

Porous metal oxide materials, particularly those comprised of silica or titania, find use in many applications such as low-k dielectric materials for microelectronics as well as chemical sensors, micro/nanofluidic devices, and catalyst substrates. For this dissertation, the focus will be on the processing of porous metal oxide materials covering two subjects: hierarchical porosity exhibited over two discrete length scales and incorporation of functional nanomaterials. To generate the porous silica materials, the technique of supercritical carbon dioxide infusion (scCO2) processing was heavily relied upon. Briefly, the scCO2 infusion processing utilizes phase selective chemistries within a pre-organized amphiphilic block copolymer template using …

Interactions And Morphology Of Triblock Copolymer - Ionic Liquid Mixtures And Applications For Gel Polymer Electrolytes, Daniel F. Miranda

Open Access Dissertations

Room temperature ionic liquids (ILs) are a unique class of solvents which are characterized by non-volatility, non-flammability, electrochemical stability and high ionic conductivity. These properties are highly desirable for ion-conducting electrolytes, and much work has focused on realizing their application in practical devices. In addition, hydrophilic and ionophilic polymers are generally miscible with ILs. The miscibility of ILs with ion-coordinating polymers makes ILs effective plasticizers for gel polymer electrolytes. Due to their unique properties, ILs present a means to realize the next generation of energy storage technology. In this dissertation, the fundamental interactions between poly(ethylene oxide) (PEO) and a variety …

Chemistry At Silicone - Inorganic Oxide Interfaces, Joseph W. Krumpfer

Open Access Dissertations

This dissertation describes research performed using siloxane polymers. This includes the reactions of siloxane polymers with inorganic oxide surfaces to form covalently attached monolayers, and the electrical properties of crosslinked silicone composite films fabricated by compounding with nickel particles. In addition to these topics, the use of contact line pinning as a practical and controllable method for the deposition of materials on superhydrophobic and chemically patterned surfaces is also described The first chapter provides a general review of siloxane polymer chemistry, focusing in particular on the relationship between molecular structure and physical properties. The use and fabrication of silicone composite …

Systematic Synthesis Of Organic Semiconductors With Variable Band Gaps, Christopher Thomas Scilla

Open Access Dissertations

Polymeric materials are attractive candidates for the fabrication of low cost, large area photovoltaic devices. Controlling the band gap of the electroactive polymer is an essential factor in optimizing the resulting devices. In this dissertation, a methodology for the synthesis of well-defined semiconducting materials with tunable band gaps is described. First, the synthesis, characterization, and computational analysis of a variety of trimers consisting of two 3-hexylthiophene units flanking a central moiety consisting of thiophene, or one of the electron donating monomers isothianaphthene or thieno[3,4,b]thiophene will be described. From this analysis the influences of the electronic and steric structure of the …

Kinetically Trapping Co-Continuous Morphologies In Polymer Blends And Composites, Le Li

Open Access Dissertations

Co-continuous structures generated from the phase separation of polymer blends present many opportunities for practical application. Due to the large interfacial area in such structures and the incompatibility between the components, such non-equilibrium structures tend to coarsen spontaneously into larger sizes and eventually form dispersed morphologies. Here, we utilize various strategies to kinetically stabilize the co-continuous structures in polymer blend systems at nano- to micro- size scales.

In the partially miscible blend of polystyrene and poly(vinyl methyl ether), we took advantage of the spinodal decomposition (SD) process upon thermal quenching, and arrested the co-continuous micro-structures by the addition of nanoparticles. …