Engineering Commons^™

Nanoscale Metal Thin Film Dewetting Via Nanosecond Laser Melting: Understanding Instabilities And Materials Transport In Patterned Thin Films, Yueying Wu

Doctoral Dissertations

Nanoscale metal thin film dewetting via laser treatment is studied in this dissertation. The purpose is to understand: 1) the spatial and temporal nature of intrinsic instabilities; and 2) mass transportation involved in dewetting pattern evolution in metal thin films as well as in lithographically patterned nanostructures; and finally 3) to explore advanced control of metallic nanostructure fabrication via the confluence of top down nanolithography and pulsed laser induced dewetting. This study includes three sections. In first section, thin film Cu-Ni alloys ranging from 2-8nm were synthesized and laser irradiated. The evolution of the spinodal dewetting process is investigated as …

Thermoresponsive Nanocomposite Hydrogels: Transparency, Rapid Deswelling And Cell Release, Yaping Hou, Ruochong Fei, Jonathan Burkes, Shin Lee, Dany Munoz Pinto, Mariah Hahn, Melissa Grunlan

Dany J. Munoz Pinto

Thermal modulation reversibly switches poly(N-isopropylacrylamide) (PNIPAAm) hydrogels between a water-swollen and a deswollen state which is useful for a variety of biomedical applications. The utility and efficiency of PNIPAAm hydrogels requires tailoring their rate of deswelling/reswelling, mechanical properties and/or optical clarity. In the current work, we prepared novel thermoresponsive nanocomposite hydrogels comprised of a PNIPAAm hydrogel matrix and polysiloxane colloidal nanoparticles (∼54 nm ave. diameter) via in situ photopolymerization of aqueous solutions of NIPAAm monomer, N, N′-methylenebisacrylamide (BIS, crosslinker), photoinitiator and 0.5–4.0 wt% polysiloxane nanoparticles (wt% solids of nanoparticles with respect to NIPAAm weight) at ∼7 °C. At these nanoparticle …

Influence Of Antimony Trioxide Nanoparticle Doping On Superconductivity In Mgb2 Bulk, Yun Zhang, S X. Dou

Faculty of Engineering - Papers (Archive)

In this work, antimony trioxide (Sb₂O₃) has been doped into MgB₂ samples to act as an additive. The doping level varies from 2.5 to 15 wt%. The effects of Sb₂O₃ addition on the lattice parameters, critical temperature (T_c), critical current density (J_c), and upper critical field (H_c2) have been investigated in detail. It has been found that Sb₂O₃ doping results in a small depression in T_c. The J_c value is 2.4 × 10³ A·cm⁻² for …

Highly Active Porous Catalysts Fabricated By Attachment Of Palladium Nanoparticles On Hierarchical Carbon Structures, Hema Vijwani

Browse all Theses and Dissertations

The effectiveness of metal-based catalysts can be significantly enhanced by increasing the available surface area relative to the volume through the creation of hierarchical nanostructures. The catalyst demonstrated here is palladium, which is a widely recognized heterogeneous catalyst suitable for a variety of industrial applications such as water purification, hydrogen storage, and electrochemical devices. In this study, a novel multi-scale supporting material developed in this group, has been used as support. It consists of micro-porous graphitic carbon with strongly attached carbon nanotubes. This can increase the surface area by orders of magnitude without increasing the size or weight while still …

Lithium-Ion Battery Anodes Of Randomly Dispersed Carbon Nanotubes, Nanofibers, And Tin-Oxide Nanoparticles, Gerard Klint Simon

Browse all Theses and Dissertations

Lithium-ion battery anodes with a nanostructure of randomly dispersed carbon nanofibers (CNFs), carbon nanotubes (CNTs), and nanoparticles of tin-oxide or silicon were fabricated and tested in order to develop high capacity, easily manufactured anodes. In these anodes, a mesh of CNTs and CNFs form a conductive network within which the nanoparticles of tin-oxide are suspended. The CNT network directs electron flow to and from the nanoparticles while accommodating their volume changes. The CNFs were intended to aid electron transport by serving as conduction channels between the CNTs and the current collector. Secondarily, the CNFs reinforce the physical structure of the …

The Development Of Silver Nanoparticles As Antiviral Agents, John Christopher Trefry

Browse all Theses and Dissertations

Silver nanoparticles (AgNPs) have received tremendous attention for their antimicrobial properties; however, many gaps in knowledge exist. To address these issues, three research objectives were examined. The first objective hypothesized AgNPs can be size selected and concentrated via tangential flow ultrafiltration. The second objective hypothesized a high-throughput method could be developed to screen nanoparticle antiviral-activity and cytotoxicity simultaneously. The third objective hypothesized AgNPs inhibit viruses by preventing viral entry.

For objective one, a tangential flow ultrafiltration scheme was tested on AgNPs synthesized via the Creighton Colloid method. AgNPs were analyzed via transmission electron microscopy. In objective two, an HIV-1 vector …