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Full-Text Articles in Engineering Science and Materials

Inkjet Printing Of Ag Nanoparticles Using Dimatix Inkjet Printer, No 2, Ming Yuan Chuang May 2017

Inkjet Printing Of Ag Nanoparticles Using Dimatix Inkjet Printer, No 2, Ming Yuan Chuang

Protocols and Reports

This report describes the rheological analysisof the present Ag nanoparticle ink, and confirms that it is suitable for the piezoelectric drop-on-demand printing for both of 1 pL and 10 pL cartridges. The satellite drops and the splashing on the substrate are also discussed for optimization of the nozzle temperature and the jetting voltage. The minimum horizontal and vertical line widths are shown to be 30 and 40 µm, respectively, but the average minimum single line width is estimated to be ~50 µm. The non-uniform width lines are suggested to arise from the bulge instability. Furthermore, it is indicated that the ...


Inkjet Printing Of Ag Nanoparticles Using Dimatix Inkjet Printer, No 1, Amal Abbas, Inayat Bajwa Jan 2017

Inkjet Printing Of Ag Nanoparticles Using Dimatix Inkjet Printer, No 1, Amal Abbas, Inayat Bajwa

Protocols and Reports

Ag nanoparticle inkjet printing on polyimide and polyethylene terephthalate films has been performed using Dimatix inkjet printer at Quattrone Nanofabrication Facility. This article describes selection of Ag nanoparticle inks and reports the progress of optimization of drop spacing, drop frequency, droplet size, and waveform for high resolution features, and furthermore reveals the pros and cons of Dimatix inkjet printing. In addition, the resistivity of Ag nanoparticle line sintered was determined to be ~2.2 x 10-5 Ωm. The adhesion and bending tests indicated that Ag nanoparticle pattern sintered on PI and PET films had exceptional mechanical stability.


Mechanics Of Colloidal Assemblies, Daniel James Strickland Jan 2017

Mechanics Of Colloidal Assemblies, Daniel James Strickland

Publicly Accessible Penn Dissertations

Amorphous solids -- solids that lack long-range order of their constituent particles -- are common in both nature and industry. Window glass, dense polymers, and food grains are three examples of amorphous solids familiar to us. In many amorphous solids, shear banding -- plastic deformation in which strain is accumulated in a thin band of the material -- is common. Consequently, many amorphous solids are brittle, a trait which has limited the technological adoption of otherwise promising materials such as metallic glasses. Therefore, a fundamental understanding of shear banding -- i.e., the progression from particle level plastic events to a macroscopic shear band, identification ...


Quantum Electronic Interference In Nano Amorphous Silicon And Other Thin Film Resistance Memory, Yang Lu Jan 2017

Quantum Electronic Interference In Nano Amorphous Silicon And Other Thin Film Resistance Memory, Yang Lu

Publicly Accessible Penn Dissertations

This thesis describes conductivity in amorphous semiconductors and insulators—some doped with metals, in which elastic electrons can random walk across a transport length of ~10 nm. At low temperatures, back diffusion of coherent electrons causes constructive quantum interference that leads to reduced diffusivity/conductivity. Rich physics also arises in this so-called weak-localization (WL) regime from electron-phase mutilation by spin-orbit interaction (weak-antilocalization or WAL) and magnetic modulation, and from Friedel-oscillation-enhanced backscattering and Zeeman splitting (electron-electron-interaction or EEI). Conductivity is analyzed by a new tool to eliminate contact resistance without using the four-point-probe method.

The Aharonov-Bohm oscillation in magnetoresistance affords the ...


Flexible, Photopatterned, Colloidal Cdse Semiconductor Nanocrystal Integrated Circuits, Franklin Scott Stinner Jan 2017

Flexible, Photopatterned, Colloidal Cdse Semiconductor Nanocrystal Integrated Circuits, Franklin Scott Stinner

Publicly Accessible Penn Dissertations

As semiconductor manufacturing pushes towards smaller and faster transistors, a parallel goal exists to create transistors which are not nearly as small. These transistors are not intended to match the performance of traditional crystalline semiconductors; they are designed to be significantly lower in cost and manufactured using methods that can make them physically flexible for applications where form is more important than speed. One of the developing technologies for this application is semiconductor nanocrystals.

We first explore methods to develop CdSe nanocrystal semiconducting “inks” into large-scale, high-speed integrated circuits. We demonstrate photopatterned transistors with mobilities of 10 cm2/Vs on ...


Cation Kinetics And Electric Field Effect In Zirconia, Yanhao Dong Jan 2017

Cation Kinetics And Electric Field Effect In Zirconia, Yanhao Dong

Publicly Accessible Penn Dissertations

Cation diffusion controls mass transport and microstructural evolution in zirconia above 1200 oC. In past research, its experimentally measured activation energy of 5 eV cannot be reproduced by computer simulation, which gives >10 eV and a cation vacancy mechanism implicating enhanced diffusion in oxidizing atmosphere, contradicting experimental evidence. This thesis was undertaken to answer these questions and to explore new ground in cation kinetics.

To help search for low-energy configurations in zirconia alloys, we employed crystal chemistry to boost sampling efficiency, by >1,000 times, and obtained plausible “ground states” to launch ab-initio calculations for cation defects and migration. The ...


Understanding Dewetting Transitions On Nanotextured Surfaces: Implications For Designing Surfaces With Improved Wettability, Suruchi Fialoke Jan 2017

Understanding Dewetting Transitions On Nanotextured Surfaces: Implications For Designing Surfaces With Improved Wettability, Suruchi Fialoke

Publicly Accessible Penn Dissertations

Despite the early promise of superhydrophobic surfaces, their widespread technological adoption has been dawdled by the ease with which water can penetrate the surface texture, resulting in a breakdown of superhydrophobicity. Furthermore, this breakdown is believed to be irreversible, because large adhesion barriers impede the dewetting of the surface texture and the concomitant recovery of superhydrophobicity. Using molecular dynamics simulations in conjunction with advanced sampling techniques, in this thesis, we challenge this conventional argument. We show that while large barriers do typically impede the recovery of superhydrophobicity, it can nevertheless be recovered spontaneously on nanotextured surfaces, wherein collective water density ...


Interfacial Assembly In Aqueous Two Phase Systems, Sarah Danielle Hann Jan 2017

Interfacial Assembly In Aqueous Two Phase Systems, Sarah Danielle Hann

Publicly Accessible Penn Dissertations

Stabilizing bio-friendly and cyto-mimetic fluid structures has important implications for drug and gene delivery, micro bio-reactors, single cell and microniche studies, and as protocells. The majority of stabilization techniques have been developed for oil-in-water and water-in-oil emulsions, which have limitations in their application to biological systems due to the presence of the oil phase. The structures built in this thesis are therefore made within water-in-water dispersions. These all water dispersions are from aqueous mixtures of two polymers that demix to form two phases, termed aqueous two phase systems (ATPSs). ATPSs are comprised of two water-rich phases and are therefore excellent ...


Mechanics Of Fluctuating Elastic Plates And Fiber Networks, Xiaojun Liang Jan 2017

Mechanics Of Fluctuating Elastic Plates And Fiber Networks, Xiaojun Liang

Publicly Accessible Penn Dissertations

Lipid membranes and fiber networks in biological systems perform important mechanical functions at the cellular and tissue levels. In this thesis I delve into two detailed problems -- thermal fluctuation of membranes and non-linear compression response of fiber networks. Typically, membrane fluctuations are analysed by decomposing into normal modes or by molecular simulations. In the first part of my thesis, I propose a new semi-analytic method to calculate the partition function of a membrane. The membrane is viewed as a fluctuating von Karman plate and discretized into triangular elements. Its energy is expressed as a function of nodal displacements, and then ...