de.mpg.escidoc.pubman.appbase.FacesBean
Deutsch
 
Hilfe Wegweiser Impressum Kontakt Einloggen
  DetailsucheBrowse

Datensatz

DATENSATZ AKTIONENEXPORT

Freigegeben

Zeitschriftenartikel

Counterion condensation and conformational transitions of polyelectrolytes characterized by EPR spectroscopy

MPG-Autoren
http://pubman.mpdl.mpg.de/cone/persons/resource/persons48040

Hinderberger,  D.
MPI for Polymer Research, Max Planck Society;

http://pubman.mpdl.mpg.de/cone/persons/resource/persons48107

Jeschke,  Gunnar
MPI for Polymer Research, Max Planck Society;

http://pubman.mpdl.mpg.de/cone/persons/resource/persons48786

Spiess,  Hans Wolfgang
MPI for Polymer Research, Max Planck Society;

Externe Ressourcen
Es sind keine Externen Ressourcen verfügbar
Volltexte (frei zugänglich)
Es sind keine frei zugänglichen Volltexte verfügbar
Ergänzendes Material (frei zugänglich)
Es sind keine frei zugänglichen Ergänzenden Materialien verfügbar
Zitation

Hinderberger, D., Jeschke, G., & Spiess, H. W. (2002). Counterion condensation and conformational transitions of polyelectrolytes characterized by EPR spectroscopy. Macromolecules, 35(26), 9698-9706.


Zitierlink: http://hdl.handle.net/11858/00-001M-0000-000F-646B-9
Zusammenfassung
Counterion condensation of multivalent, charged spin probes to highly charged cationic and anionic polyelectrolytes is characterized by CW and FT EPR spectroscopy. Line broadening and deviation from Lorentzian line shape in the EPR spectra of the spin probes are observed upon addition of the polyelectrolyte. These effete are due to dynamic electrostatic attachment of the counterions with exchange between the condensed and free states on a subnanosecond time scale. The spectral changes can be separated into a contribution due to slowdown of rotational dynamics and a contribution due to enhanced spin exchange. drastic increase of the spin-exchange contribution is observed upon increasing the concentration of two anionic spin probes in aqueous solutions of the cationic polyelectrolyte poly(diallyldimethylammonium chloride), PDADMAC. This can be traced back to a counterion-induced chain collapse which is, however, not observed in mixtures of water with organic solvents of either higher (N-methylpropionamide) or lower (ethanol) permittivity. Simple polyelectrolyte theory, which considers solvents only as a dielectric continuum, cannot explain these findings. Screening of hydrophobic interactions between repeat units of the chain by the organic solvents is suggested as an explanation.