[ChBE-Grad] ChBE Seminar this Friday

[Solano, Nicolette]

UH ChBE Dept. Seminar
10:30am-11:30am, Friday, February 5, 2016
Room L2D2
Precise Polymers that Control Nanoscale Morphologies & Properties
Karen I. Winey
University of Pennsylvania



ABSTRACT: Acid- and ion-containing polymers have specific interactions that produce hierarchical nanoscale morphologies containing acid- or ion-rich aggregates.  As new synthetic methods produce polymers with greater molecular precision, the uniformity of and control over these complex structures has increased.  We have studied a series of precise polymer synthesized by acyclic diene metathesis (ADMET) chemistry that have functional groups evenly spaced along linear polyethylenes.  The functional groups include carboxylic acid, phosphoric acid, imidazolium bromide, and more recently sulfur containing functional groups (sulfite, sulfone and sulfonic acid).  We have established design rules connecting these precise polymers to particular hierarchical morphologies.  As our attention turns toward transport and mechanical properties, these unprecedented morphologies provide an opportunity to understand and manipulate properties.  Using in situ X-ray scattering and tensile testing, we’ve identified three distinct mechanical responses and their corresponding morphology evolutions.  For example, when acrylic acid groups are separated by 15 carbons, the precise copolymer exhibits a structural transformation from a nominally spherical to a layered aggregate morphology during tensile deformation that coincides with substantial strain hardening.


Bio: Karen I. Winey is Professor and TowerBrook Foundation Faculty Fellow of Materials Science and Engineering at the University of Pennsylvania with a secondary appointment in Chemical and Biomolecular Engineering.  Prof. Winey characterizes and manipulates nanoscale morphologies in various ionomers and associating polymers to discover materials with advanced mechanical and transport properties.  In particular, she has quantitatively reconciled scattering, imaging and spectroscopic data to describe the morphologies in styrene-based ionomers and discovered new morphologies in several acid-containing precise polyethylenes.  Winey also designs and fabricates polymer nanocomposites to understand and improve their mechanical, thermal, and especially electrical properties, which includes a novel method for extracting the contact resistance in nanowire-based transparent conductors.  Polymer diffusion in the presence of nanoparticles and other types of nanoconfinement is a newer area of interest.  In both areas, she couples experimental studies with simulation and theory, either within her group or with collaborators. Winey received her B.S. from Cornell University in materials science and engineering and her Ph.D. in polymer science and engineering from the University of Massachusetts, Amherst with Ned Thomas as her thesis advisor.  Following a postdoctoral position at AT&T Bell Laboratories with Ron Larson, she joined the faculty of the University of Pennsylvania in 1992.  Elected positions include chair of the Polymer Physics Gordon Research Conference (2010) and Chair of the Division of Polymer Physics within the American Physical Society (2013).  Winey also served as an Associate Editor for Macromolecules for four years (2010-14).  Her honors include Fellow of the American Physical Society (2003), Special Creativity Award from the National Science Foundation (2009-2011), George H. Heilmeier Faculty Award for Excellence in Research (2012), Fellow of the Materials Research Society (2013), Visiting Miller Research Professor at the University of California, Berkeley (2014), and Fellow of the PMSE Division within the American Chemical Society (2016).














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