Bulletin of the American Physical Society
APS March Meeting 2020
Volume 65, Number 1
Monday–Friday, March 2–6, 2020; Denver, Colorado
Session A68: 100 Years of Polymer ScienceInvited Undergrad Friendly
|
Hide Abstracts |
Sponsoring Units: DPOLY Chair: Connie Roth, Emory University Room: Four Seasons 4 |
Monday, March 2, 2020 8:00AM - 8:36AM |
A68.00001: Equilibration and Dynamics in Block Copolymer Micelles Invited Speaker: Timothy Lodge Block copolymers provide a remarkably versatile platform for achieving desired nanostructures by self-assembly, with lengthscales ranging from a few nanometers up to several hundred nanometers. In particular, block copolymer micelles in selective solvents are of great interest across a range of technologies, including drug delivery, imaging, catalysis, lubrication, and extraction. While block copolymers generally adopt the morphologies familiar in small molecule surfactants and lipids (i.e., spherical micelles, worm-like micelles, and vesicles), one key difference is that polymeric micelles are typically not at equilibrium. The primary reason is the large number of repeat units in the insoluble block, Ncore, which makes the thermodynamic penalty for extracting a single chain (“unimer exchange”) substantial. As a consequence, the critical micelle concentration (CMC) is rarely accessed experimentally; however, in the proximity of a critical micelle temperature (CMT), equilibration is possible. We use time-resolved small angle neutron scattering (TR-SANS) to obtain a detailed picture of the mechanisms and time scales for chain exchange, for systems at or near equilibrium. The dependence of the rate of exchange on the key variables – concentration, temperature, Ncore, Ncorona, and chain architecture (diblock versus triblock) – will be discussed. We will also address measurements of micelles prepared far from equilibrium, which equilibrate by fragmentation processes, using dynamic light scattering, small-angle X-ray scattering, and liquid-state TEM. |
Monday, March 2, 2020 8:36AM - 9:12AM |
A68.00002: Polymers Science in Modeling Mushy, Squishy Systems Invited Speaker: Anna Balazs Chemical Engineering Dept., University of Pittsburgh, Pittsburgh, PA 15261 |
Monday, March 2, 2020 9:12AM - 9:48AM |
A68.00003: Progress in understanding entangled polymer dynamics Invited Speaker: Scott Milner The surprising flow behavior of entangled polymer melts and solutions has been a subject of enduring interest. In the last 30 years, substantial progress has been made in mechanistic understanding of entangled polymer rheology, based on the tube ansatz of Edwards and de Gennes. I will summarize the essential physics of the “success stories”: 1) linear dynamic rheology of entangled linear chains, stars, star-linear blends, H-polymers, polydisperse multiply branched chains, and polydisperse linear chains; and 2) nonlinear extensional flow of linear chains and branched polymers. |
Monday, March 2, 2020 9:48AM - 10:24AM |
A68.00004: Computer Simulations of Entangled Polymer Melts: From Segmental Dynamics to Viscoelastic Response Invited Speaker: Gary Grest From the first numerical simulations of single polymer chains in dilute solution to current exascale simulations of highly entangled polymer melts, computer simulations have played a critical role in polymer physics. Numerical simulations have provided microscopic insight into macroscope behavior. Here the potential of computations to polymer physics in the realm of new computer architectures will be introduced in view of the fundamental insight connecting theory and experiments attained thus far. Capturing the wide range of coupled length and time scales that govern the unique macroscopic, viscoelastic behavior of polymers has been one of the major challenges to surmount. Starting with the simple bead-spring models, through atomistically inspired coarse-grained approaches, it is now possible to capture not only the mobility of the chain but also the viscoelastic properties of entangled polymers. With current and future computational resources, numerical simulations will provide the understanding of viscoelastic response and shear and extensional viscosity of entangled melts for complex architectures bridging the dynamics on the length scale of the atomic level with the macroscopic response. |
Monday, March 2, 2020 10:24AM - 11:00AM |
A68.00005: Application of Polymer Physics to tissue viscoelasticity: Entangled active matter Invited Speaker: Francoise Brochard-Wyart
|
Follow Us |
Engage
Become an APS Member |
My APS
Renew Membership |
Information for |
About APSThe American Physical Society (APS) is a non-profit membership organization working to advance the knowledge of physics. |
© 2024 American Physical Society
| All rights reserved | Terms of Use
| Contact Us
Headquarters
1 Physics Ellipse, College Park, MD 20740-3844
(301) 209-3200
Editorial Office
100 Motor Pkwy, Suite 110, Hauppauge, NY 11788
(631) 591-4000
Office of Public Affairs
529 14th St NW, Suite 1050, Washington, D.C. 20045-2001
(202) 662-8700