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Search Publications by: Jason Killgore (Fed)

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Displaying 26 - 50 of 71

Tunable Mechanical Anisotropy, Crack Guiding, and Toughness Enhancement in Two-Stage Reactive Polymer Networks

June 13, 2019
Author(s)
Lewis M. Cox, Adrienne K. Blevins, Jasper A. Drisko, Yifu Ding, Callie I. Higgins, Rong Long, Christopher N. Bowman, Jason P. Killgore
Photopolymers are a versatile group of materials that enable intricate geometric control over printed part geometries in advanced manufacturing processes. However, manufacturing methods attempting to spatially control material heterogeneity within printed

Controlled Growth of Polyamide Films atop Homogeneous and Heterogeneous Hydrogels using Gel- Liquid Interfacial Polymerization

May 22, 2019
Author(s)
Mengyuan Wang, Christopher Stafford, Lewis M. Cox, Adrienne K. Blevins, Masoud Aghajani, Jason Killgore, Yifu Ding
Interfacially polymerized polyamide (PA) layers dictate the permselective performance of thin film composite (TFC) membranes. Extensive effort has been focused on understanding and ultimately controlling the structure and morphology of the PA layers on

Nanomechanics of cellulose deformation reveal molecular defects that facilitate natural deconstruction

April 29, 2019
Author(s)
Peter Ciesielski, Ryan Wagner, Vivek Bharadwaj, Jason Killgore, Ashutosh Mittal, Gregg Beckham, Stephen Decker, Michael Himmel, Michael Crowley
Technologies surrounding utilization and processing of cellulosic materials have been important to human society for millennia. As with many materials, achieving a molecular-level understanding of the formation, characteristics, and functionality of

Monitoring Fast, Voxel-Scale Cure Kinetics via Sample-Coupled-Resonance Photorheology

February 13, 2019
Author(s)
Callie I. Higgins, Lewis M. Cox, Frank W. DelRio, Jason P. Killgore
Photopolymerizable materials are the focus of extensive research across a variety of fields ranging from additive manufacturing to regenerative medicine. However, poorly understood material mechanical and rheological properties during polymerization at the

Nanoscale Hygromechanical Behavior of Lignin

September 22, 2018
Author(s)
Kristen M. Hess, Jason Killgore, Wil Srubar
The nanoscale hygromechanical behavior of lignin is presented in this work. Three atomic force microscopy experimental methods were used to correlate moisture sorption of lignin to its mechanicalbehavior. First, sorption isotherms were established using

A Readily Programmable, Fully Reversible Shape Switching Material

August 24, 2018
Author(s)
Matthew McBride, Alina Martinez, Lewis M. Cox, Marvin Alim, Kimberly Childress, Michael Beiswinger, Maciej Podgorski, Brady Worrell, Jason Killgore, Christopher N. Bowman
Liquid crystalline elastomers (LCEs) enable large scale reversible shape changes in polymeric materials; however, they require intensive, irreversible programming approaches to facilitate controllable actuation. We have implemented photo-induced dynamic

AFM Scan Speed Phenomena

March 21, 2018
Author(s)
Jason P. Killgore, Christopher C. Glover, Ryan Tung
This work presents data confirming the existence of a scan speed related phenomenon in contact mode atomic force microscopy. Specifically, contact resonance spectroscopy is used to interrogate this phenomenon. A monotonic decrease in the recorded contact

Determination of the True Lateral Grain Size in Organic-Inorganic Halide Perovskite Thin Films

October 4, 2017
Author(s)
Gordon A. MacDonald, Chelsea Heveran, Mengjin Yang, David Moore, Kai Zhu, Virginia L. Ferguson, Jason Killgore, Frank W. DelRio
In this letter, methylammonium lead iodide (MAPbI3) thin films were examined via piezoresponse force microscopy (PFM) and nanoindentation (NI) to determine if long range atomic order existed across the full width of the apparent grains. From the PFM, the

Formation of a crack-free, hybrid skin layer with tunable surface topography and improved gas permeation selectivity on elastomers using gel-liquid infiltration polymerization

September 11, 2017
Author(s)
Justin Gorham, Jason Killgore, Maryam Omidvar, Haiqing Lin, Frank W. DelRio, Lewis M. Cox, Zheng Zhang
Liquid-liquid interfacial polymerization (ll-IP) is conventionally used for manufacturing bulk polymers like nylon, as well as forming barrier layers for reverse osmosis membranes. In this work, we explore the use of gel-liquid infiltration polymerization

Light-stimulated Permanent Shape Reconfiguration in Crosslinked Polymer Microparticles

April 7, 2017
Author(s)
Lewis M. Cox, Xiaohao Sun, Chen Wang, Nancy Sowan, Jason Killgore, Rong Long, Hengan Wu, Christopher N. Bowman, Yifu Ding
Covalent adaptable networks (CANs) are cross-linked polymer networks capable reconfiguring their network topology, enabling stress relaxation and shape changing behaviors. Reversible addition-fragmentation chain transfer (RAFT) is one specific mechanism by

Reconstructing the Distributed Force on an Atomic Force Microscope Cantilever

February 7, 2017
Author(s)
Ryan Wagner, Jason P. Killgore
A methodology to reconstruct a distributed force applied to an atomic force microscopy (AFM) cantilever given the shape in which it vibrates is developed. This is accomplished by rewriting Bernoulli Euler beam theory such that the force on the cantilever

Methylammonium lead iodide grain boundaries exhibit depth-dependent electrical properties

September 23, 2016
Author(s)
Gordon A. MacDonald, Mengjin Yang, Samuel Berweger, Jason Killgore, Pavel Kabos, Joeseph Berry, Kai Zhu, Frank W. DelRio
In this letter, the nanoscale through-film and lateral photoresponse and conductivity of large-grained methylammonium lead iodide thin films are studied. In perovskite solar cells (PSC), these films result in efficiencies > 17%. The top surface of the