Dresden 2009 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
CPP: Fachverband Chemische Physik und Polymerphysik
CPP 18: Polyelectrolytes
CPP 18.5: Vortrag
Dienstag, 24. März 2009, 10:30–10:45, ZEU 114
Intermediate states in the coil to globule transition of polyacrylate chains: Single chain structures in dilute aqueous solutions and on surfaces — •Prashant Sinha1, Sebastian Lages2, Anton Kiriy1, Manfred Stamm1, and Klaus Huber2 — 1Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Strasse 6, 01069 Dresden, Germany — 2Chemsitry Department, Universität Paderborn, Warburger Str.100, D-33098 Paderborn, Germany
A cascade of intermediate states appear along the coil to globule transition of polyacrylate chains in dilute aqueous solutions during interactions with specifically binding ions. Conformational changes of these chains induced by Sr2+, Pb2+ and Ca2+ ions have been studied. In the last case, temperature has been introduced as a secondary parameter to substantiate recent findings that the binding of carboxylate groups with calcium ions may be entropic in nature. The samples were characterized using combined static and dynamic light scattering. Intermediate states which exhibited a drastic reduction of coil dimensions upon addition of stoichiometric amounts of specifically binding ions were then investigated for single chain structures using SAXS, ASAXS and SANS, as suitable. The very same samples were also investigated on mica surfaces using Atomic Force Microscopy. Various characteristics of the single chain structures of intermediate states, primarily radius of gyration, have been compared for dilute solution behavior and surface behavior. We believe that the results provide one of the rare direct visual evidences of the coil to globule transition in a regime investigated also through scattering.