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Dynamics and Structure of Biopolyelectrolytes characterized by Dielectric Spectroscopy

Structural properties of Na-DNA and Na-HA aqueous solutions can be quantified using dielectric spectroscopy in the frequency range 100 Hz - 100 MHz. Two relaxation modes are typically detected that can be attributed to diffusive motion of polyion counterions. The overall study as a function of polyion length, concentration and added salt concentration demonstrates that the motion of polyion counterions detected at MHz frequencies probes collective properties, whereas the motion at kHz range probes single-chain properties of polyelectrolytes. Fundamental length scales found to characterize the polyelectrolyte structure differ for the dilute and semidilute regime and also depend on the strength of electrostatic interactions and the flexibility. Characteristic length scales detected in the dielectric spectroscopy measurements compare well with the fundamental length scales predicted by theory and comply with those extracted from small-angle X-ray scattering.

biomaterials; dielectric properties; polyelectrolytes; dynamics and conformational changes; small-angle X-ray scattering

Special Issue: Polymer Spectroscopy. Rad je prezentirasn na skupu The 18th European Symposium on Polymer Spectroscopy (ESOPS 18) održanom od 19.-22.09.2011., Zadar, Hrvatska.