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Search Publications by: Kathryn L. Beers (Fed)

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Displaying 26 - 50 of 97

INVESTIGATING THE MECHANISM OF ENZYME-CATALYZED RING-OPENING COPOLYMERIZATIONS

August 19, 2012
Author(s)
Matthew T. Hunley, Fahriye N. Sari, Kathryn L. Beers
As the research interest in degradable polymers has risen, an ever increasing number of manuscripts report the synthesis of copolymers through ring-opening copolymerization techniques. However, the mechanism of copolymerization remains unexplored. In

Solid-Phase Synthesis of Ammonium Ionenes

June 24, 2012
Author(s)
Matthew T. Hunley, Kathryn L. Beers
Ionenes are polyelectrolytes with the charge along the polymer backbone. These polymers possess a precisely-defined charge density, making them ideal as physical crosslinkers for high performance elastomers as well as gene transfection agents. However

SOLID-SUPPORTED ENZYME CATALYST MODELS FOR RING-OPENING POLYMERIZATION

April 27, 2012
Author(s)
Sara V. Orski, Santanu S. Kundu, Kathryn L. Beers, Richard A. Gross
The enzyme Candida antarctica Lipase B (CAL B), immobilized on a crosslinked poly(methyl methacrylate) (PMMA) support, catalyzes the ring-opening polymerization of ε-caprolactone to make biodegradable polyesters. Weak hydrophobic interactions of CAL B

In Situ Raman Monitoring of Ring-Opening Copolymerizations

March 25, 2012
Author(s)
Matthew T. Hunley, Santanu S. Kundu, Peter M. Johnson, Kathryn Beers
Recent advances in enzyme, metal, and organic catalysts have enabled the development of advanced functional polymers from cyclic ester and cyclic carbonate monomers. In this work, we present an in situ technique to monitor ring-opening polymerization using

Stability of Solid-Supported Enzyme Catalysts for Ring-Opening Polymerization

March 19, 2012
Author(s)
Sara V. Orski, Santanu S. Kundu, Kathryn L. Beers, Richard Gross
The enzyme Candida antarctica Lipase B (CAL B), immobilized on a crosslinked poly(methyl methacrylate) (PMMA) support, catalyzes the ring-opening polymerization of ε-caprolactone to make biodegradable polyesters. Weak hydrophobic interactions of CAL B

Control of Molecular Mass Distributions in Enzymatic Lactone Polymerizations

February 2, 2012
Author(s)
Santanu S. Kundu, Peter M. Johnson, Kathryn L. Beers
Using a model developed for the enzyme catalyzed polymerization and degradation of poly(caprolactone), we illustrate methods and the kinetic mechanisms necessary to improve molecular mass distributions by manipulating equilibrium reactions in the kinetic

In situ monitoring of enzyme-catalyzed (co)polymerizations by Raman spectroscopy

November 10, 2011
Author(s)
Matthew T. Hunley, Atul Bhangale, Santanu S. Kundu, Peter M. Johnson, Michael S. Waters, Richard Gross, Kathryn Beers
In situ, fiber optic-based Raman spectroscopy provided real time monitoring of enzyme-catalyzed ring-opening homo- and copolymerizations of ε-caprolactone (ε-CL) and δ-valerolactone (δ-VL). A custom designed reactor equipped with in situ fiber optic probe

Modeling Enzymatic Kinetic Pathways for Ring-Opening Lactone Polymerization

August 11, 2011
Author(s)
Peter M. Johnson, Santanu S. Kundu, Kathryn Beers
A unified kinetic pathway for the enzyme catalyzed polymerization and degradation of poly(ε-caprolactone) was developed. This model tracks the complete distribution of individual chain lengths, both enzyme-bound and in solution, and successfully predicts

MSEL Sustainability Seminar Series (2009)

May 15, 2011
Author(s)
Winnie K. Wong-Ng, Kathryn L. Beers, Richard E. Ricker, Martin L. Green
An MSEL Sustainability Seminar Series took place in 2009, aimed at the following goals: (1) to introduce this important subject matter to our staff and (2) to learn and discuss the metrology needs for materials for sustainability applications. Since

CONTINUOUS FLOW ENZYME-CATALYZED POLYMERIZATION IN A MICROREACTOR

March 25, 2011
Author(s)
Santanu S. Kundu, Atul S. Bhangale, William E. Wallace, Kathleen M. Flynn, Charles M. Guttman, Richard Gross, Kathryn L. Beers
Enzymes immobilized on solid supports are increasingly used for chemical transformation because the process is greener and sustainable. Here we use microreactors to study enzyme catalyzed ring opening polymerization of -caprolactone to polycaprolactone. A

Gradient Solvent Vapor Annealing of Block Copolymer Thin Films Using a Microfluidic Mixing Device

February 9, 2011
Author(s)
Kathryn L. Beers, Michael J. Fasolka, Julie N. Albert, Timothy D. Bogart, Ronald L. Lewis, J. Brian Hutchison, Bryan D. Vogt, Thomas H. Epps
Solvent vapor annealing (SVA) with solvent mixtures is a promising approach for controlling block copolymer thin film self-assembly. In this work, we present the design and fabrication of a solvent-resistant microfluidic mixing device to produce discrete

Challenges in Sustainable Polymeric Materials

May 19, 2010
Author(s)
Kathryn L. Beers, Christopher M. Stafford
While there are many societal and economic factors that contribute to a sustainable civilization, there are also real technical and scientific problems that must be solved to provide the materials necessary to make progress towards the goal of

Gradient and Microfluidic Library Approaches to Polymer Interfaces

January 1, 2010
Author(s)
Michael J. Fasolka, Christopher M. Stafford, Kathryn L. Beers
We present and overview of research conducted at the National Institute of Standards and Technology aimed at developing combinatorial and high throughput measurement approaches to polymer surfaces, interfaces and thin films. Topics include, 1) the

IMMOBILIZED ENZYME CATALYZED POLYMERIZATION REACTIONS IN MICROREACTORS

January 1, 2010
Author(s)
Santanu S. Kundu, Atul Bhangale, William E. Wallace, Kathleen M. Flynn, Richard Gross, Kathryn L. Beers
Application of microreactor technologies enable improved safety, selectivity and yield in a range of chemical reactions in addition to new measurement methods that are often faster, cheaper and more accurate than traditional methods. In this study we have

IMPACT OF IMMOBILIZATION SUPPORTS FOR POLYESTERS SYNTHESIS ACTIVITY OF CANDIDA ANTARTICA LIPASE B

January 1, 2010
Author(s)
Atul Bhangale, Santanu S. Kundu, Wenchun Xie, William E. Wallace, Kathleen M. Flynn, Kathryn L. Beers, Richard Gross
Epoxy functionalized supports are known to be suitable for industrial-scale immobilization of enzymes for biocatalysis. However, chemistry across these epoxy groups is known to affect the catalytic performance of the enzymes.In order to achieve a balance

Living Anionic Polymerization Using a Microfluidic Reactor

January 15, 2009
Author(s)
Thomas Q. Chastek, Kazunori Iida, Eric J. Amis, Michael J. Fasolka, Kathryn L. Beers, Jae H. Chun
Living anionic polymerizations were conducted within aluminum-polyimide microfluidic devices. Polymerizations of styrene in cyclohexane were carried out at various conditions, including elevated temperature (60 °C) and high monomer concentration (42 %, by

Monitoring Polymerization in Microfludic Flow Channels Using Spectroscopy Methods

October 16, 2008
Author(s)
Anthony J. Bur, Zuzanna T. Cygan, Kathryn L. Beers, Susan E. Barnes
A micro-fluidic device, designed as a high throughput system for characterizing polymerizations over a range of solvent, monomer, initiator and temperature conditions, was instrumented with a fluorescence spectrometer. A fluorescent dye, incorporated into

Surface Patterning Using Microchannel-Confined Surface Transformation ( ST)

October 16, 2008
Author(s)
Chang Xu, Kathryn L. Beers
Most surface patterned polymer brushes synthesized to date contain only one type of polymer and the remaining surface areas are either bare substrate or SAM. To further control the entire surface area, several methods have been developed to fabricate

Measurement of Reactivity Ratios in Surface-Initiated Copolymerization

August 21, 2007
Author(s)
Derek L. Patton, Kirt A. Page, Chang Xu, Kirsten Genson, Michael J. Fasolka, Kathryn L. Beers
This work describes a new approach to measure monomer reactivity ratios from surface-initiated copolymerizations using x-ray photoelectron spectroscopy. Styrene/methyl methacrylate statistical copolymer brushes were prepared from various monomer feeds by

Microfluidic Dynamic Light Scattering Used for High Throughput Measurements

July 10, 2007
Author(s)
Thomas Q. Chastek, Kathryn L. Beers, Eric J. Amis
When diluted in some solvents, surfactants and block copolymers self-assemble into micelles or vesicles of about 10-100 nm in size. There is a great deal of interest in micelles and vesicles because they are widely used in the formulations industry, and

NCMC Workshop ReportNCMC-10: Persistent Challenges in Combinatorial Materials Science

February 1, 2007
Author(s)
Michael J. Fasolka, Carol E. Laumeier, Kathryn L. Beers, Christopher M. Stafford
Tremendous advances in the development and application of combinatorial and high-throughput methods for materials research have been accomplished over the past 15 years. Despite these accomplishments, today s combinatorial materials science is met by some