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Search Publications by: Chad R. Snyder (Fed)

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Displaying 1 - 25 of 80

Self-Assembly of Hierarchical High-h Fluorinated Block Copolymers with an Orthogonal Smectic-within-Lamellae 3 nm Sub-Lattice and Vertical Surface Orientation

April 16, 2024
Bijal Patel, Hongbo Feng, Whitney Loo, Chad R. Snyder, Christopher Eom, Julia Murphy, Daniel Sunday, Paul Nealey, Dean DeLongchamp
Hierarchical structure-within-structure assemblies offer a route toward increasingly complex and multifunctional materials while pushing the limits of block copolymer self-assembly. We present a detailed study of the self-assembly of a series of

Evaluating Models That Predict Epoxy Conversion Using Rheological Properties

April 15, 2024
Stian Romberg, Paul Roberts, Chad R. Snyder, Anthony Kotula
Simultaneous rheology and conversion measurements of neat and composite epoxy resins reveal that conventional models neither accurately nor fully describe the relationship between rheology and conversion. We find that models predicting thermoset conversion

Assessing Composite Structure in Metal-Organic Framework-Polymer Mixed-Matrix Membranes

March 15, 2024
Avery Baumann, Peter Beaucage, Richard Vallery, David Gidley, Ryan Nieuwendaal, Chad R. Snyder, Jan Ilavsky, Fu Chen, Christopher Stafford, Christopher Soles
Metal-organic frameworks (MOFs) are renowned for their tunable structure, porosity, and internal chemistry with demonstrated applications in molecular separations, storage, and conversion. While they are widely usable, the powdery characteristics of MOF

Temperature Dependence of Kinetic Friction: A Handle for Plastics Sorting?

February 26, 2024
Chad R. Snyder, Kalman Migler
Sortation is a crucial step in mechanical recycling of post-consumer plastics (PCR) whereby properties such as density or spectral signature are used to separate plastics. However it is difficult to sort polyolefin flakes at high throughput by these

Correlating the Diffusion of Water in Model Polyamides with Controlled Crosslink Densities to the Performance in Reverse Osmosis Membranes for Desalination

April 18, 2023
Velencia Witherspoon, Kanae Ito, Chad R. Snyder, Madhusudan (Madhu) Tyagi, Tyler Martin, Peter Beaucage, Ryan Nieuwendaal, Richard Vallery, David Gidley, Jeffrey Wilbur, Dean Welsh, Christopher Stafford, Christopher Soles
To elucidate robust design cues for improving the active polyamide (PA) filtration layers in reverse osmosis (RO) membrane for desalination, we systematically reduce the cross-link density of a PA network based on m-phenylene diamine by substituting a

Crystallization Kinetics in an Immiscible Polyolefin Blend

December 12, 2022
Derek Huang, Anthony Kotula, Chad R. Snyder, Kalman Migler
Motivated by the problem of brittle mechanical behavior in recycled blends of high density polyethylene (HDPE) and isotactic polypropylene (iPP), we employ optical microscopy, rheo-Raman, and differential scanning calorimetry (DSC) to measure the

Imaging 3D molecular orientation by orthogonal-pair polarization IR microscopy

February 28, 2022
Shuyu Xu, Chad R. Snyder, Jeremy Rowlette, Young Jong Lee
Anisotropic molecular alignment occurs ubiquitously and often heterogeneously in three dimensions (3D). However, conventional imaging approaches based on polarization can map only molecular orientation projected onto the 2D polarization plane. Here, an

Predicting the plateau modulus from molecular parameters of conjugated polymers

January 18, 2022
Abigail Fenton, Renxuan Xie, Melissa Aplan, Youngmin Lee, Michael Gill, Ryan Fair, Fabian Kempe, Michael Sommer, Chad R. Snyder, Enrique Gomez, Ralph Colby
The relationship between Kuhn length lk, Kuhn monomer volume v0, and plateau modulus GN0 , initially proposed by Graessley and Edwards for flexible polymers, and extended by Everaers, has a large gap in experimental data between the flexible and stiff

Measuring Tie Chains and Trapped Entanglements in Semicrystalline Polymers

September 21, 2021
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

Polymer Additive Manufacturing: Confronting Complexity

June 19, 2019
Anthony P. Kotula, Jonathan E. Seppala, Chad R. Snyder
Since its development and commercialization in the 1980s, polymer additive manufacturing (AM) has become a disruptive technology. In this chapter we describe the ever-increasing demands for polymer AM in industry, academia, and government, as well as the


June 19, 2019
Jonathan E. Seppala, Anthony P. Kotula, Chad R. Snyder

Morphology of a thermally stable small molecule OPV blend comprising a liquid crystalline donor and fullerene acceptor

June 4, 2019
Alexander J. Bourque, Sebastian Engmann, Allison Fuster, Chad R. Snyder, Lee J. Richter, Paul B. Geraghty, David J. Jones
Recently organic photovoltaic (OPV) devices comprising the small molecule liquid-crystalline donor, benzodithiophene-quaterthiophene-rhodanine (BQR), were demonstrated to achieve high performance when thermally processed, avoiding the need for slow-drying

Aggregation and Solubility of a Model Conjugated Donor-Acceptor Polymer

July 31, 2018
Daniel R. Reid, Nicholas E. Jackson, Alexander J. Bourque, Chad R. Snyder, Ronald L. Jones, Juan de Pablo
In organic semiconductors, solution-phase polymer structure and aggregation have a strong influence on device morphology and performance. Thus, understanding solubility of conjugated polymers is crucial for their rational design. Using a combination of

Characterization of Interfacial Structure in Polymer-Fullerene Bulk Heterojunctions via 13C {2H} Rotational Echo Double Resonance NMR

July 13, 2018
Ryan C. Nieuwendaal, Dean M. DeLongchamp, Martin Heeney, Jan Hummelen, Chad R. Snyder, Ronald L. Jones, Sebastian Engmann, Lee J. Richter, Zhuping Fei, Alex Sieval
We introduce a new application of solid state NMR measurements towards characterizing the donor-acceptor interfaces within bulk heterojunction (BHJ) films. Rotational echo double resonance (REDOR) is used to measure dipolar couplings between 13C nuclei on

Design and Implementation of pyPRISM: A Polymer Liquid-State Theory Framework

June 15, 2018
Tyler B. Martin, Thomas E. Gartner, Ronald L. Jones, Chad R. Snyder, Arthi Jayaraman
Polymer Reference Interaction Site Model (PRISM) theory describes the equilibrium spatial- correlations, thermodynamics, and structure of liquid- like polymer systems and macromolecular materials. Here, we describe the code structure, implementation, and

pyPRISM Documentation

May 11, 2018
Tyler B. Martin, Thomas E. Gartner, Ronald L. Jones, Chad R. Snyder, Arthi Jayaraman

pyPRISM Tutorial

May 11, 2018
Tyler B. Martin, Thomas E. Gartner, Ronald L. Jones, Chad R. Snyder, Arthi Jayaraman

Alkane Encapsulation Induces Strain in Small Diameter Single-Wall Carbon Nanotubes

May 4, 2018
Jason K. Streit, Jochen I. Campo, Chad R. Snyder, Ming Zheng, Jeffrey R. Simpson, Angela R. Hight Walker, Jeffrey Fagan
Encapsulation of linear alkane molecules in the endohedral volumes of small diameter single- wall carbon nanotubes (SWCNTs) is shown to induce diameter dependent strain on the hexagonal lattice of carbon atoms composing the tubular structure. For the

Glassy Phases in Organic Semiconductors

March 17, 2018
Chad R. Snyder, Dean M. DeLongchamp
Organic semiconductors may be processed from fluids using graphical arts printing and patterning techniques to create complex circuitry. Because organic semiconductors are weak van der Waals solids, the creation of glassy phases during processing is quite