Engineering Commons^™

Deformation And Adhesion Of Soft Composite Systems For Bio-Inspired Adhesives And Wrinkled Surface Fabrication, Michael Imburgia

Doctoral Dissertations

The study of soft material deformation and adhesion has broad applicability to industries ranging from automobile tires to medical prosthetics and implants. When a mechanical load is imposed on a soft material system, a variety of issues can arise, including non-linear deformations at interfaces between soft and rigid components. The work presented in this dissertation embraces the occurrence of these non-linear deformations, leading to the design of functional systems that incorporate a soft elastomer layer with application to bio-inspired adhesives and wrinkled surface fabrication. Understanding the deformation of a soft elastomer layer and how the system loading and geometry influence …

Fabric And Soft Materials Composites For Bio-Inspired Adhesives And Prosthetics, Daniel R. King

Doctoral Dissertations

Adhesives have long been designed around a trade-off between adhesive strength and releasability. Within this spectrum, specialized materials have been designed to maximize adhesive ability for a given application. To overcome this trade-off, a new adhesive paradigm is required. Biologically inspired adhesives have been of interest over the past two decades, because organisms are seen using their adhesive pads to achieve high adhesive forces, while maintaining releasability and reusability. Many biological organisms possess microscopic fibrillar features on their toe-pads, which enables climbing. While much effort has been spent attempting to mimic these features, ultimately high force capacities have not been …

Patterning And Mechanical Analysis Of Fiber-Based Materials, Samuel A. Pendergraph

Doctoral Dissertations

The ability to define and control the topography of a surface has been studied extensively due to its importance in a wide variety of applications. The control of a non-planar topography would be very valuable since a number of structures that are pervasive in artificial applications (e.g. fibers, lenses) are curved interfaces. This potential of enabling applications that incorporate non-planar geometries was the motivation for this thesis. The first study of this thesis comprises the study of patterning the circumference of micrometer sized fibers. Specifically, a unique technique was described to pattern the fiber with a periodic array of colloids. …

Scaling Reversible Adhesion In Synthetic And Biological Systems, Michael David Bartlett

Open Access Dissertations

Geckos and other insects have fascinated scientists and casual observers with their ability to effortlessly climb up walls and across ceilings. This capability has inspired high capacity, easy release synthetic adhesives, which have focused on mimicking the fibrillar features found on the foot pads of these climbing organisms. However, without a fundamental framework that connects biological and synthetic adhesives from nanoscopic to macroscopic features, synthetic mimics have failed to perform favorably at large contact areas. In this thesis, we present a scaling approach which leads to an understanding of reversible adhesion in both synthetic and biological systems over multiple length …

Surface Instabilities For Adhesion Control, Chelsea Simone Davis

Open Access Dissertations

Controlling the specific adhesive properties of surfaces is a technologically complex challenge that has piqued the interest of many research groups around the world. While many scientists have used complex topographic and chemically altered surfaces to tune adhesion, others have shown that naturally occurring phenomena, such as elastic instabilities, can impact adhesion. We provide a thorough investigation into the effects of periodic surface buckling instabilities, or wrinkles, on adhesion. Wrinkles are an attractive surface patterning alternative as they form spontaneously over large areas and their dimensions, namely wavelength and amplitude, can be controlled on length scales relevant for adhesion control. …

Supercritical Fluid Deposition Of Thin Metal Films: Kinetics, Mechanics And Applications, Christos Fotios Karanikas

Doctoral Dissertations 1896 - February 2014

In order to meet the demands of the continuous scaling of electronic devices, new technologies have been developed over the years. As we approach the newest levels of miniaturization, current technologies, such as physical vapor deposition and chemical vapor deposition, are reaching a limitation in their ability to successfully fabricate nano sized electronic devices.

Supercritical fluid deposition (SFD) is a demonstrated technology that provides excellent step coverage for the deposition of metals and metal oxides within narrow, high aspect ratio features. This technique shows the potential to satisfy the demands of integrated circuit miniaturization while maintaining a cost effective process …