Determination of charge and molecular weight of rigid-rod polyelectrolytes.
J Phys Chem B
; 111(29): 8344-7, 2007 Jul 26.
Article
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| MEDLINE
| ID: mdl-17547440
ABSTRACT
Rod-like polyelectrolytes are an interesting model system because their persistence length is independent of the ionic strength and pH of the surrounding medium and they permit the investigation of polyelectrolytes in the absence of conformational degrees of freedom. In this work, rigid-rod poly(aramide) polyelectrolytes were synthesized by the Higashi method. Electrophoresis NMR spectroscopy in conjunction with diffusion NMR spectroscopy has been applied to determine the effective charge of the polymer. The charge was determined from the balance between the force in the electric field and the hydrodynamic friction in the steady-state electrophoretic motion. Because only organic counterions were present, and were identified in the proton NMR spectra, the counterions were investigated as well, and the fraction of condensed counterions was determined directly. From the effective charge per molecule and the knowledge of the fraction of condensed counterions, the total charge per molecule was determined. Finally, from the total charge, the number of repeat units and thus the molecular weight were inferred.
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Colección:
01-internacional
Banco de datos:
MEDLINE
Idioma:
En
Revista:
J Phys Chem B
Asunto de la revista:
QUIMICA
Año:
2007
Tipo del documento:
Article
País de afiliación:
Alemania