Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Search Publications by: Ryan Nieuwendaal (Fed)

Search Title, Abstract, Conference, Citation, Keyword or Author
Displaying 1 - 21 of 21

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

A method to quantify composition, purity, and cross-link density of the polyamide active layer in reverse osmosis composite membranes using 13C cross-polarization magic angle spinning nuclear magnetic resonance spectroscopy

February 12, 2022
Ryan Nieuwendaal, Christopher Stafford, Jeff Wilbur
A method for harvesting and purifying the thin polyamide (PA) active layer from thin-film composite (TFC) reverse osmosis (RO) membranes was developed, enabling quantitative nuclear magnetic resonance (NMR) measurements of the composition and cross-linking

Enhanced Conductivity via Homopolymer-Rich Pathways in Block Polymer-Blended Electrolytes

December 24, 2019
Melody A. Morris, Seung Hyun Sung, Priyanka M. Ketkar, Joseph Dura, Ryan Nieuwendaal, III Epps
The optimization of ionic conductivity and lithium-ion battery stability can be achieved by independently tuning the ion transport and mechanical robustness of block polymer (BP) electrolytes. However, the ionic conductivity of BP electrolytes is

Effect of temperature on the structure and dynamics of triblock copolymer coacervate hydrogels

July 16, 2018
Vivek M. Prabhu, Ryan C. Nieuwendaal, Anand Rahalkar, Juan J. DePablo, Samanvaya Srivastava, Matthew Tirrell
Triblock copolymer coacervate gels were characterized by small-angle neutron scattering (SANS) and dynamic light scattering. The oppositely charged polyelectrolyte complex core size does not change with temperature. However, the neutral middle block that

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

Structure and Order in Organic Semiconductors

January 17, 2017
Chad R. Snyder, Dean M. DeLongchamp, Ryan C. Nieuwendaal, Andrew A. Herzing
Several techniques for characterizing semiconducting polymer order on different length scales are presented, including (1) differential scanning calorimetry (DSC), (2) solid state nuclear magnetic resonance spectroscopy (NMR), (3) transmission electron

Supramolecular Self-assembly of a Novel Hydrogelator: Characterization of Fiber Morphology and Formation and Thermal-Reversible Gelation

October 8, 2016
Jack F. Douglas, Yuan Gao Yuan Gao, Ryan C. Nieuwendaal, Emilios Dimitriadis, Boualem Hammouda, Bing Xu, Ferenc Horkay
Hydrogels are of intense recent interest in connection with biomedical applications ranging from 3-D cell cultures and stem cell differentiation to regenerative medicine, controlled drug delivery and tissue engineering. This prototypical form of soft

Structure Elucidation of Mixed-Linker Zeolitic Imidazolate Frameworks by Solid-State 1H CRAMPS NMR Spectroscopy and Computational Modeling

May 23, 2016
Ryan C. Nieuwendaal, Krishna Jayachandrababu, Ross Verploegh, Johannes Leisen, David Sholl, Sankar Nair
Mixed-linker zeolitic imidazolate frameworks (ZIFs) are nanoporous materials that exhibit continuous and controllable tunability of properties like effective pore size, hydrophobicity and organophilicity. The structure of mixed-linker ZIFs has been studied

How to measure absolute P3HT crystallinity via 13C CPMAS NMR

April 20, 2016
Ryan C Nieuwendaal
We outline the details of acquiring quantitative 13C cross-polarization magic angle spinning (CPMAS) NMR spectra on the most ubiquitous polymer for organic electronics (OE) applications, poly(3-hexylthiophene) (P3HT), despite other groups’ claims that

Classification of Semiconducting Polymeric Mesophases to Optimize Device Post-Processing

August 17, 2015
Chad R. Snyder, Regis J. Kline, Dean M. DeLongchamp, Ryan C. Nieuwendaal, Lee J. Richter, Martin Heeney, Iain McCulloch
Semiconducting polymers form a variety of phases and mesophases that respond differently to post-deposition solvent or thermal treatments. Here it is shown that classification of these materials into their appropriate mesophases can be a useful tool to

Quantifying Crystallinity in High Molar Mass Poly(3-hexylthiophene)

June 3, 2014
Chad R. Snyder, Ryan C. Nieuwendaal, Dean M. DeLongchamp, Christine K. Luscombe, Prakash Sista, Shane D. Boyd
We extend a recent comprehensive study of 3-hexylthiophene oligomers to high molar mass poly(3-hexylthiophene) (P3HT) fractions, such as those used in organic photovoltaic devices. Through a combination of differential scanning calorimetry (DSC) and 13C

Comparison of the Properties of Cellulose Nanocrystals and Cellulose Nanofibrils Isolated From Bacteria, Tunicate, and Wood Processed Using Acid, Enzymatic, Mechanical, and Oxidative Methods

April 18, 2014
Iulia A. Sacui, Jeffrey W. Gilman, Ryan C. Nieuwendaal, Stephan J. Stranick, Henryk Szmacinski, Mehdi Jorfi, Christopher Weder, Johan Foster, Richard Olsson, Daniel Burnett
This work describes the study and characterization of native cellulose nanocrystals and nanofibrils (CNCs, CNFs), whose crystallinity, morphology, aspect ratio, and surface chemistry depend on the raw material source and hydrolysis conditions. Measurement

Measuring order in regioregular poly(3-hexylthiophene) with solid-state 13C CPMAS NMR

January 10, 2014
Ryan C. Nieuwendaal, Chad R. Snyder, Dean M. DeLongchamp
We report on details of molecular packing in high molar mass poly(3-hexylthiophene) (P3HT) by solid-state 13C {1H} cross-polarization magic angle spinning (CPMAS) NMR measurements. The degree of polymer order was estimated for two films of varied drying

Formation of Extended Ionomeric Network by Bulk Polymerization of L,D-lactide with Layered Double Hydroxide

November 22, 2012
Edward D. McCarthy, Mauro Zammarano, Douglas M. Fox, Ryan Nieuwendaal, Yeon S. Kim, P H. Maupin, Paul C. Trulove, Jeffrey W. Gilman
We report the formation of an ionomeric network in a poly(L,D-lactide) hybrid nanocomposite, (PLDLA-HYB) during in-situ melt polymerization of L,D lactide in the presence of magnesium/aluminium layered-double-hydroxide (LDH) without added catalyst. The

Measuring domain sizes and compositional heterogeneities in P3HT-PCBM bulk heterojunction thin films with 1H spin diffusion NMR spectroscopy

March 21, 2012
Ryan C. Nieuwendaal, Hyun Wook Ro, David Germack, Regis J. Kline, Calvin Chan, Amit K. Agrawal, David J. Gundlach, David L. VanderHart, Dean M. DeLongchamp
In this manuscript we show that 1H spin diffusion NMR is a valuable method for estimating the domain sizes in thin films of a polymer-fullerene blend for bulk heterojunction (BHJ) photovoltaics. Variations in common BHJ film processing parameters have

Polymer Dynamics in Constrained Geometries

February 1, 2012
Christopher Soles, Ryan Nieuwendaal, Huagen H. Peng
The wide-spread interest in the dynamical property of organic materials under strong states of confinement largely began with differential scanning calorimeter (DSC) measurements in the early 90's of the glass transition and heat capacity of glass forming