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© 2005 Thomas Ettore Angelini counterion behavior architectural polymorphism synchrotron radiation x-ray diffraction biopolymers counterion Wong, Gerard C.L. Angelini, Thomas 2012-06-27T19:12:33Z 2012-06-27T19:12:33Z 10000-01-01 2006 Counterion behavior controls interactions between charged surfaces in aqueous environments, and can cause attraction between like charged objects. Mean field approaches to describing counterion behavior, such as the Poisson-Boltzmann formalism and Manning condensation theory, predict that charged surfaces are renormalized by a surrounding counterion cloud or condensed counterion layer, but such mean field approaches never predict an attraction. However, a large number of theoretical studies have shown that by accounting for counterion correlations, attractive forces between like charged objects can be predicted. In this work we present the first observations of counterion correlations in charged polymer systems. At the ~60 Å scale, we used small angle x-ray scattering to observe that the counterions in F-actin bundles adopt a periodic distribution, forming a one-dimensional charge density wave. At the ~5 Å scale, we used high-resolution inelastic x-ray scattering to observe inter-ion correlations. From the dissipative dynamics of an unexpected acoustic phonon-mode associated with the counterions, we show that the counterions behave as a dense hard-sphere fluid and obtain an inter-ion distance which can be controlled by changing ion number density within the bundles. Finally, we show how counterion behavior impinges on bundles of specifically linked protein filaments, and observe an architectural polymorphism which can be controlled by monovalent salt concentration. Submitted by Megan O'Donnell (mnodonn2@illinois.edu) on 2012-06-27T19:12:33Z No. of bitstreams: 1 Angelini_Thomas.pdf: 3373466 bytes, checksum: 7d41f9c9cdcbd258634fbc597625a2bb (MD5) Made available in DSpace on 2012-06-27T19:12:33Z (GMT). No. of bitstreams: 1 Angelini_Thomas.pdf: 3373466 bytes, checksum: 7d41f9c9cdcbd258634fbc597625a2bb (MD5) Previous issue date: 2006 Item marked as restricted to the 'UIUC Users [automated]' Group (id=2) by Megan O'Donnell (mnodonn2@illinois.edu) on 2012-06-27T19:12:33Z Item is restricted indefinitely. Restriction data tranferred 2014-07-01T11:33:05-05:00 Original Data Group with Access UIUC Users [automated] Release Date: none Reason: dissertation/thesis dissertation/thesis U of I Only 5235142 http://hdl.handle.net/2142/31906 en Deoxyribonucleic Acid (DNA) Counterion Behavior in Biopolymers Dissertation / Thesis text Physics Physics University of Illinois at Urbana-Champaign Dissertation Ph.D.