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Displaying 101 - 125 of 1856

Activation of Mechanophores in a Thermoset Matrix by Instrumented Scratch

November 17, 2021
Author(s)
Chelsea S. Davis, Jeremiah Woodcock, Ryan Beams, Mitchell Rencheck, Muzhou Wang, Stephan J. Stranick, Aaron M. Forster, Jeffrey Gilman
Scratches in polymer coatings and barrier layers negatively impact optical properties (haze, light transmission, etc.), initiate routes of degradation or corrosion (moisture permeability), and nucleate delamination of the coating. Detecting scratches in

Solvent-cast 3D Printing of Biodegradable Polymer Scaffolds

October 22, 2021
Author(s)
John Tolbert, Diana Hammerstone, Nathaniel Yuchimiuk, Jonathan Seppala, Lesley Chow
Three-dimensional (3D) printing is a popular technique to fabricate scaffolds for tissue engineering because of its ability to produce complex tissue-like architectures. Scaffolds are often 3D printed using biodegradable polymers like poly(caprolactone)

Imperfect Surface Order and Functionalization in Vertical Carbon Nanotube Arrays Probed by Near Edge X-ray Absorption Fine Structure Spectroscoy (NEXAFS)

October 12, 2021
Author(s)
T Hemraj-Benny, S Banerjee, S Sambasivan, Daniel A. Fischer, G Eres, Alexander Puretzky, David B. Geohegan, D H. Lowndes, J A. Misewich, S S. Wong
Probing surface order in nanotube systems is of fundamental importance for incorporation of these materials into practical electronic devices. The current study pertains to analysis of the surface orientation of vertically aligned single-walled and multi

Measuring Tie Chains and Trapped Entanglements in Semicrystalline Polymers

September 21, 2021
Author(s)
Amanda G. McDermott, Paul DesLauriers, Jeff Fodor, Ronald L. Jones, Chad R. Snyder
A label-free method for quantifying stress-transmitter (or elastically effective molecule) content (p) in semicrystalline polymers, including both tie molecules and bridging entanglements, is developed and demonstrated based on swelling with deuterated

Side Chain Engineering Control of Mixed Conduction in Oligoethylene Glycol-Substituted Polythiophenes

August 31, 2021
Author(s)
Jonathan Onorato, Zhongyang Wang, Yangyang Sun, Christian Nowak, Ban Dong, Lucas Flagg, Ruipeng Li, Lee J. Richter, Fernando Escobedo, Paul Nealey, Shrayesh Patel, Christine Luscombe
A major limitation for polymeric mixed ionic/electronic conductors (MIECs) is the trade-off between ionic and electronic conductivity; changes made that improve one typically hinder the other. In order to address this fundamental problem, this work

Polarized X-ray scattering measures molecular orientation in polymer-grafted nanoparticles

August 12, 2021
Author(s)
Subhrangsu Mukherjee, Dean DeLongchamp, Eliot Gann, Daniel Sunday, Lee J. Richter, Jason Streit, Richard A. Vaia, Baskar Ganapathysubramanian, Kumar Saurabh, Adarsh Krishnamurthy
Polymer chains are attached to nanoparticle surfaces for many purposes, including altering solubility, influencing aggregation, dispersion, and even tailoring immune responses in drug delivery. The most unique structural motif of polymer-grafted

Temperature-insensitive silicone composites as ballistic witness materials: the impact of water content on the thermophysical properties

July 28, 2021
Author(s)
Ran Tao, Fan Zhang, Huong Giang Nguyen, Philip Bernstein, Amanda L. Forster, Randy Mrozek, Aaron M. Forster
In this work, different formulations of a room-temperature silicone composite backing material (SCBM) composed of polydimethylsiloxane (PDMS), fumed silica and corn starch were investigated using different characterization techniques, i.e., differential

Simulated filament shapes in embedded 3D printing

July 22, 2021
Author(s)
Leanne Friedrich, Jonathan Seppala
Embedded 3D printing, wherein fluid inks are extruded into a bath, has enabled the manufacture of complex, custom structures ranging from cell-laden tissue analogues to soft robotics. This method encompasses two techniques: embedded ink writing (EIW)

Fluorescence Microscopy Reveals Structure-Property Relationships and Polymer Dynamics in Biocomposites

July 21, 2021
Author(s)
Quinn Easter, Shawn Chen, Jeremiah Woodcock, Amanda Souna, Sindhu Seethamraju, Jan Obrzut, Douglas M. Fox, Stephan J. Stranick, Jeffrey Gilman
OBJECTIVES: Developing the next generation of materials for use in restorative work requires a multifaceted approach. While mimicking the properties of the tooth, currently available dental composites and porcelains eventually fail and require replacement

Supersonic Impact Response of Polymer Thin Films via Large-Scale Atomistic Simulations

July 15, 2021
Author(s)
Andrew L. Bowman, Edwin P. Chan, William B. Lawrimore, John K. Newman
Recent nanoscale ballistic testing studies have shown the applicability of nanomaterials for ballistic protection but have raised new questions regarding the nanoscale structure-property relationships that contribute to the enhanced ballistic response of

Molecular Mass Dependence of Interfacial Tension in Complex Coacervation

June 11, 2021
Author(s)
Debra Audus, Samim Ali, Artem Rumyantsev, Yuanchi Ma, Juan J. de Pablo, Vivek Prabhu
The interfacial tension of coacervates, the liquidlike phase composed of oppositely charged polymers that coexists at equilibrium with a supernatant, forms the basis for multiple technologies. Here we present a comprehensive set of experiments and

Buried Structure in Block Copolymer Films Revealed by Soft X-ray Reflectivity

May 20, 2021
Author(s)
Daniel Sunday, Jacob L. Thelen, R Joseph Kline, Chun Zhou, Jiaxing Ren, Paul Nealey
Interactions between polymers and surfaces can be used to influence properties including mechanical performance in nanocomposites, the glass transition temperature, and the orientation of thin film block copolymers (BCPs). In this work we investigate how

Fabrication of 3D Printed Hydroxyapatite Composite Scaffolds for Bone Regeneration

May 19, 2021
Author(s)
Yoontae Kim, Eun-Jin Lee, Albert Davydov, Stanislav Frakhtbeyen, Jonathan Seppala, Laurence Chow, Tagaki Shozo, Stella Alimperti
Additive biomanufacturing has been adapted in a wide variety of biomedical and tissue engineering applications, including orthopedics. The ability to print biocompatible, patient-specific geometries with controlled porosity, mechanical strength has made

Orientational ordering within semiconducting polymer fibrils

May 2, 2021
Author(s)
Subhrangsu Mukherjee, Eliot Gann, Masrur M. Nahid, Terry McAfee, Andrew Herzing, Dean DeLongchamp, Harald W. Ade
Due to a general paucity of suitable characterization methods, the internal orientational ordering of polymer fibrils has rarely been measured despite its importance particularly for semi-conducting polymers. An emerging tool with sensitivity to bond

Estimations of the effective Young's modulus of specimens prepared by fused filament fabrication

April 5, 2021
Author(s)
Lichen Fang, Yishu Yan, Ojaswi Agarwal, Jonathan Seppala, Kalman D. Migler, Thao D. Nguyen, Kevin Hemker, Sung Hoon Kang
The elastic response of homogeneous isotropic materials is most commonly represented by their Young's modulus (E), but geometric variability associated with additive manufacturing results in materials that are neither homogeneous nor isotropic. Here we
Displaying 101 - 125 of 1856