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Search Publications by: Jason Killgore (Fed)

Displaying 126 - 146 of 146

Hydrodynamic Corrections to Contact Resonance Force Microscopy Measurements of Viscoelastic Loss Tangent

July 9, 2013

Author(s)

Ryan C. Tung, Jason P. Killgore, Donna C. Hurley

We present a method to improve accuracy in measurements of nanoscale viscoelastic material properties with contact resonance (CR) AFM methods. Through the use of the two-dimensional hydrodynamic function, we obtain a more precise estimate of the fluid

Anomalous Friction in Suspended Graphene

September 20, 2012

Author(s)

Alexander Y. Smolyanitsky, Jason P. Killgore

Since the discovery of the Amonton's law and with support of modern tribological models, friction between surfaces of three-dimensional materials is known to generally increase when the surfaces are in closer contact. Here, using molecular dynamics

Quantitative Viscoelastic Mapping of Polyolefin Blends with Contact Resonance Atomic Force Microscopy

May 9, 2012

Author(s)

Dalia Yablon, Anil Gannepalli, Roger Proksch, Jason Killgore, Donna C. Hurley, Andy Tsou

The storage modulus (E') and loss modulus (E") of polyolefin blends have been mapped on the nanoscale with contact resonance force microscopy (CR-FM), a dynamic contact mode of atomic force microscopy (AFM). CR-FM maps for a blend of polyethylene

Relationship between Barrier Layer Tg and TFC Membrane Performance: Effect of Chlorine Treatment

March 8, 2012

Author(s)

Sajjad H. Maruf, Dae U. Ahn, John Pellegrino, Jason Killgore, Alan R. Greenberg, Yifu Ding

Thin film composite (TFC) reverse osmosis (RO) membranes play a significant role in addressing rapidly expanding global needs for potable water. A well-known problem of TFC membranes is their sensitivity to oxidizing agents such as chlorine, which are used

Pulsed Contact Resonance in the Atomic Force Microscope

January 30, 2012

Author(s)

Jason P. Killgore, Donna C. Hurley

Low Force AFM Nanomechanics with Higher-Eigenmode Contact Resonance Spectroscopy

January 11, 2012

Author(s)

Jason P. Killgore, Donna C. Hurley

Atomic force microscopy (AFM) methods for quantitative measurements of elastic modulus on stiff (>10 GPa) materials typically require tip-sample contact forces in the hundreds of nanonewton to few micronewton range. Such large forces can incur sample

Effect of elastic deformation on frictional properties of few-layer graphene

January 9, 2012

Author(s)

Alexander Y. Smolyanitsky, Jason P. Killgore, Vinod K. Tewary

We describe the results of Brownian dynamics (BD) simulations of an AFM tip scanned on locally suspended few-layer graphene. The effects of surface compliance and sample relaxation are directly related to the observed friction force. We demonstrate that

Viscoelastic Property Mapping with Contact Resonance Force Microscopy

November 4, 2011

Author(s)

Jason P. Killgore, Donna C. Hurley, Dalia Yablon, Joseph Turner, Philip Yuya, Roger Proksch, Anil Gannepalli, Andy Tsou

We demonstrate accurate nanoscale mapping of loss and storage modulus on a polystyrene-polypropylene blend with contact resonance force microscopy (CR-FM). The viscoelastic properties are extracted from spatially resolved maps of the contact resonance

Quantitative Subsurface Contact Resonance Force Microscopy of Model Polymer Nanocomposites

March 16, 2011

Author(s)

Jason P. Killgore, Jennifer Y. Kelly, Christopher M. Stafford, Michael J. Fasolka, Donna C. Hurley

We present experimental results on the use of quantitative contact resonance force microscopy (CR-FM) for mapping the planar location and depth of 50 nm silica nanoparticles buried beneath polystyrene films 30 nm to 165 nm thick. The presence of shallowly

In-Situ Measurement of Atomic Force Microscope Tip Wear by Contact Resonance Force Microscopy

March 15, 2011

Author(s)

Jason P. Killgore, Roy H. Geiss, Donna C. Hurley

Contact resonance force microscopy (CR-FM) mapping provides a means of continuously tracking contact stiffness while scanning an AFM tip in contact with a substrate. Because the contact stiffness is a function of contact radius, tip wear leading to changes

Deciphering Piezoelectric and Surface Charge Effects in Hydroxyapatite Osteoconduction via Piezoresponse Force Microscopy

November 30, 2002

Author(s)

Youngjoon Han, Jeongjae Ryu, Andreas Schiffer, Jason Killgore, Seungbum Hong

Electrical properties of hydroxyapatite (HAp), the main constituent of the mineralized portion of the cortical bone, and a key variable in Wolff's law, remain an enigma up to this date. In order to make a comparison between the contribution of the