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Kiriy, A. ; Gorodyska, G. ; Minko, S. ; Jaeger, W. ; Stepánek, P. ; Stamm, M.
Cascade of Coil-Globule Conformational Transitions of Single Flexible Polyelectrolyte Molecules in Poor Solvent

We show that hydrophobic flexible polyelectrolyte molecules of poly(2-vinylpyridine) and poly(methacryloyloxyethyl dimethylbenzylammonium chloride) are trapped and frozen due to adsorption on the mica surface, and the observed AFM single molecule structures reflect the molecular conformation in solution. An increase of the ionic strength of the solution induces the cascade of abrupt conformational transitions due to the intrachain segregation from elongated coil to compact globule conformations through intermediate pearl necklace-globule conformations with different amounts of beads per chain. The length of the necklaces and the number of beads decrease, while the diameter of beads increases with the increase of ionic strength. Coexistence at the same time of extended coils, necklaces with different amounts of beads, and compact globules indicates the cascade of the first-order-type phase transitions.

Quelle
Journal of the American Chemical Society 124

Seiten
13454-13462

DOI
http://dx.doi.org/10.1021/ja0261168

Erschienen am
November 2002
 
Publications
Publications

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Nanostructured Materials