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Displaying 926 - 950 of 3439

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

Synthesis and characterization of antimicrobial dimethacrylates containing quaternary ammonium functionalities for dental and biomedical applications

October 27, 2011
Author(s)
Joseph M. Antonucci, Diana N. Zeiger, Sheng Lin-Gibson, Bruce O. Fowler, Nancy J. Lin
The widespread incidence of recurrent caries has resulted in the need for improved dental restorative materials, including effective antibacterial, polymeric dental materials. Compounds with quaternary ammonium groups are known to reduce bacterial growth

Influence of chain stiffness on thermal and mechanical properties of polymer thin films

October 25, 2011
Author(s)
Jessica M. Torres, Chengqing C. Wang, E. B. Coughlin, John P. Bishop, Richard A. Register, Robert A. Riggleman, Christopher Stafford, Bryan D. Vogt
The effect of main chain stiffness and side chain flexibility on the elastic modulus and glass transition temperature (Tg) of thin polymer films is investigated using non-traditional polymers formed from 5-(2-phenylethylnorbornene). Depending on the

Morphological Changes Driven by Nanofibrous Scaffolds Induce Marrow Stromal Cell Osteogenesis

October 11, 2011
Author(s)
Carl G. Simon Jr., Kaushik Chatterjee, Christopher K. Tison, Girish Kumar, Patrick S. Pine, Marc L. Salit, Jennifer H. McDaniel, Marian F. Young
Cells are sensitive to tissue scaffold architecture and these cell-material interactions drive cell functions critical in tissue regeneration. Results presented here demonstrate that nanofiber scaffolds force primary human bone marrow stromal cells (hBMSCs

Block copolymer photonic gel for mechanochromic sensing

September 19, 2011
Author(s)
Edwin Chan, Joseph J. Walish, Edwin L. Thomas, Christopher Stafford
In this work, we describe a strategy based on mechanochromic sensing, the coupling between mechanical and optical properties, of a block copolymer photonic gel. Although this phenomena has been observed in many materials, we demonstrate this concept for

Characterizing the Mechanical Properties and Degradation of Thin Polymer Membranes

August 28, 2011
Author(s)
Christopher M. Stafford, Jun Y. Chung, Junghyun Lee
The elasticity, strength, and toughness of thin polymer membranes are of considerable interest since direct knowledge of these key mechanical properties can provide insight into performance, durability, and underlying degradation mechanisms that occur over

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

Using Block Copolymer Self-Assembly to Imprint the Crystallization of Polymer Dendrites

August 10, 2011
Author(s)
Sangcheol Kim, Alamgir Karim, Jack F. Douglas, Christopher L. Soles, R M. Briber
We utilize the self-assembly of cylinder-forming block copolymer (BCP) films to create templates for dendritic polymer crystallization patterns. This templating was achieved by simply spin-casting thin films from a solution containing both the BCP

Analyses of a Cantilever-Beam Based Instrument for Evaluating the Development of Polymerization Stresses

August 9, 2011
Author(s)
Martin Chiang, Anthony A. Giuseppetti, Joy Dunkers, Jing Qian, Sheng Lin-Gibson, Gary E. Schumacher, Joseph M. Antonucci
Analytical and finite element analyses have been performed on a cantilever-beam based methodology (tensometer) for evaluating the development of stresses as the concomitant of constrained polymerization shrinkage. A guideline for designing a tensometer

Design and Optimization of a Permeation Testing System for Polymer Coatings

August 8, 2011
Author(s)
Adrian E. Verwolf
Measurements of liquid permeation through freestanding Parylene C membranes were made using a high- performance testing system, which demonstrated fast response (≤ 30 seconds) to changing concentrations in the sweep gas stream and detectability of less
Displaying 926 - 950 of 3439
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