Bulletin of the American Physical Society
APS March Meeting 2010
Volume 55, Number 2
Monday–Friday, March 15–19, 2010; Portland, Oregon
Session H4: Polymer Physics Prize |
Hide Abstracts |
Sponsoring Units: DPOLY Chair: Hyuk Yu, University of Wisconsin-Madison Room: Oregon Ballroom 204 |
Tuesday, March 16, 2010 8:00AM - 8:36AM |
H4.00001: Polymer Physics Prize Talk: Our Love Story with Polymers or ``Is This Really Physics?'' Invited Speaker: Some recent results and remaining open questions in several areas of polymer physics ranging from polymer entanglements to reversible gels and polyelectrolytes will be reviewed and put into historical and sociological perspective. [Preview Abstract] |
Tuesday, March 16, 2010 8:36AM - 9:12AM |
H4.00002: Designing Ion-Containing Polymers for Facile Ion Transport Invited Speaker: We synthesize single-ion conducting ionomers with low glass transition temperatures to prepare ion conducting membranes for actuators and lithium battery separators. We use dielectric spectroscopy to determine the number density of conducting ions and their mobility from electrode polarization (using the 1953 Macdonald model) and the number density of ion pairs from measured dielectric constant (using the 1936 Onsager model). This experimental work concludes that the number density of conducting ions is tiny, and we discuss ways to boost that using more polar polymers with weak-binding anions attached to the chain. We use \textit{ab initio} quantum chemical calculations at 0 K in vacuum to characterize ion interactions and ion solvation by various functional groups on ion-containing polymers. Simple ideas for estimating the ion interactions and solvation at practical temperatures and dielectric constants are presented that indicate the rank ordering observed at 0 K in vacuum should be preserved. Hence, such \textit{ab initio} calculations are useful for screening the plethora of combinations of polymer-ion, counterion and polar functional groups, to decide which are worthy of synthesis for new ionomers. The results provide estimates of parameters for a simple four-state model for counterions in ion-containing polymers: free ions, isolated ion pairs, triple ions and quadrupoles. We show some examples of how \textit{ab initio} calculations can be used to understand experimental observations of dielectric constant, glass transition temperature and conductivity of polymerized ionic liquids with either lithium or ionic liquid counterions. [Preview Abstract] |
Tuesday, March 16, 2010 9:12AM - 9:48AM |
H4.00003: Why Brownian yet Anomalous? The Importance of Pausing Invited Speaker: Recently, many processes of random diffusion were reported with Brownian-like time dependence of observables (such as particle displacements), but with anomalous correlations between variations of these observables during different time intervals. We demonstrate that such behavior is a characteristic feature of a large class of random processes that can be described by a sequence of random events (such as particle displacements), separated by random time intervals (pausing times). We explain this phenomenon using a simple model of a particle hopping between adsorption sites. In this model, the particle is captured between hops in a potential well for a pausing time that depends on the depth of this well. The unexpected feature of our model is that the particle experiences Brownian random motion with diffusion coefficient that depends on prior history of the particle. Abnormal character of such Brownian diffusion is manifested in the exponential (non-Gaussian) distribution function of particle displacements and anomalous time dependence of their moments. Another interesting feature of this process is the memory of a displacement of the particle affecting its motion during later time intervals. We point out, that this phenomenon is a generic feature of dynamic systems with extremely wide distribution of pausing times. [Preview Abstract] |
Tuesday, March 16, 2010 9:48AM - 10:24AM |
H4.00004: A block copolymer approach to the pre-programmed organization of inorganic nanostructures Invited Speaker: Organized arrays of inorganic nanoparticles show electronic, optical, and magnetic properties that originate from the coupling of size- and shape-dependent properties of individual nanoparticles (NPs). Controllable and predictable organization of NPs in complex, hierarchical structures provides a route to the fabrication of new materials and functional devices. Significant progress has been achieved in the bottom-top organization of NPs arrays, which is based on their self-assembly, yet, currently, this approach remains largely empirical. We propose a block copolymer paradigm for the self-assembly of asymmetric inorganic nanorods. By using a striking analogy between amphiphilic ABA triblock copolymers and inorganic nanorods carrying distinct ligands at the edges and ling sides, we assembled the nanorods in structures with varying geometries. The self-assembly was tunable and reversible, and it was achieved solely by changing the solvent quality for the constituent ``blocks''. We mapped the self-assembly process by using phase-like diagrams and demonstrated control over the optical properties of the self-assembled structures. The proposed strategy provides a new route to the organization of nanoparticles by using the strategies that are established for the self-assembly of block copolymers. [Preview Abstract] |
Tuesday, March 16, 2010 10:24AM - 11:00AM |
H4.00005: Carbon nanotubes soldering for high performance composites Invited Speaker: Individual carbon nanotubes exhibit very interesting mechanical and electric properties. At present carbon nanotubes are available in large quantities and, in principle, they should find their way as filler of choice for polymer composites. Yet, in practice, carbon nanotube composites often show deceiving properties. In this presentation we will introduce the concept of carbon nanotubes soldering discuss some promising examples of its applications to design high performance composites. In particular we will demonstrate the utility of nanotube soldering to attain high temperature mechanical and solvent resistance, properties essential for many composite applications. Work done in collaboration with Thomas P\'{e}ri\'{e} and Sylvie Tenc\'{e}-Girault. [Preview Abstract] |
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