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Search Publications by: Christopher Stafford (Fed)

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Displaying 276 - 300 of 394

Adhesion at layer-by-layer surfaces in aqueous environments

February 15, 2009
Author(s)
Adam J. Nolte, Jun Y. Chung, Marlon L. Walker, Christopher M. Stafford
Adhesion between materials is often governed by the ambient environment, which can mediate or change the types of molecular interactions present at an interface. Biological interactions, for example, can be mediated by factors such as temperature, ionic

Subsurface Patterning and its Effect on Interfacial Adhesion

February 15, 2009
Author(s)
Edwin P. Chan, Christopher M. Stafford
Nature (e.g. geckos and insects) has illustrated that a patterned surface can effectively tailor the adhesion of an interface. Inspired by the amazing attachment and detachment ability of these animals, significant efforts have been put forth to understand

Ultrathin Adhesives: Confinement Effect on Modulus

February 15, 2009
Author(s)
Jessica M. Torres, Christopher Stafford, Bryan D. Vogt
In this work, we will employ this wrinkling metrology to extract the modulus of polymer thin films for a homologous series of poly(n-alkyl methacrylate)s. In particular, we take advantage of the decrease in Tg as the alkyl chain length increases for these

In-situ Adhesion Measurements Utilizing Layer-by-layer Functionalized Surfaces

January 7, 2009
Author(s)
Adam J. Nolte, Jun Y. Chung, Marlon L. Walker, Christopher Stafford
The adhesion between poly(dimethylsiloxane) (PDMS) hemispheres coated with layer-by-layer (LbL) assemblies of polyelectrolytes was investigated using Johnson, Kendall, and Roberts (JKR) contact mechanics. Measurements were performed against amine

Complex micropatterning of periodic structures on elastomeric surfaces

July 10, 2008
Author(s)
Arnaud Chiche, Christopher Stafford, J Cabral
We report a simple methodology to fabricate complex sub-micron periodic structures in poly(dimethylsiloxane) over large surface areas (several cm2). Single-frequency, uni- and multi-axial sinusoidal surface modulations, with tunable amplitude and

Measuring the Modulus of Hydrated Contact Lenses via Surface Wrinkling

April 6, 2008
Author(s)
Jun Y. Chung, Young Jong Lee, Peyton Hopson, Michael J. Fasolka, Christopher Stafford
One of the most important considerations in the evaluation of hydrogels for biomedical and contact lens applications is the elastic modulus. The elastic modulus relates to several important factors including flexibility, comfort, adhesion, swelling

Quantifying Interfacial Adhesion in Transfer Printing via a Cantilever Peel Test

April 6, 2008
Author(s)
Jiong Liu, Jun Y. Chung, Christopher Stafford
Transfer printing has been demonstrated as a fabrication method for flexible organic electronics. The transfer printing process relies on the differential adhesion of a printable layer (PL) that is pressed between two substrates: transfer substrate (TS)

Synthesis and Characterization of Polymer Brushes from PDMS Surfaces

April 6, 2008
Author(s)
Heqing Huang, Adam J. Nolte, Jun Y. Chung, Christopher Stafford
In recent years, poly(dimethylsiloxane) (PDMS) has found increased application in the areas of microfluidic devices, chromatographic packing materials and membranes, as well as in medical and drug delivery devices. However, the hydrophobic surface of PDMS

High throughput adhesion testing using a modified edge lift-off test

February 17, 2008
Author(s)
Jiong Liu, Martin Chiang, Michael J. Fasolka, Christopher Stafford
The strength of an adhesively bonded joint depends on a host of factors such as surface treatment, roughness, materials properties, cure conditions and environmental variables. Therefore testing of adhesion within this large parameter space can be very

JKR Adhesion Testing Between Biologically Relevant Surfaces

February 17, 2008
Author(s)
Adam J. Nolte, Heqing Huang, Christopher Stafford
In this work we report recent observations obtained using an adhesion testing device that utilizes the contact mechanics theory of Johnson, Kendall, and Roberts (JKR). Our goal is to develop a system capable of measuring adhesive forces between