Electrical polarizability of polyelectrolytes by Monte Carlo simulation

COLL 366

Kazuo Kikuchi, Department of Life Sciences (Chemistry), Department of Life Sciences (Chemistry), Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo, 153-8902, Japan
Anisotropy of the electrical polarizability of model DNA fragments in salt-free aqueous solutions was determined by Monte Carlo simulation. According to the fluctuation-dissipation theorem, the electrical polarizability of polyelectrolytes is related to the fluctuations of the dipole moment generated in the counterion atmosphere around the polyion in the absence of an applied electric field. We could give a definition of condensed counterions for charged oligomers based on the simulation and the fraction of condensed counterions so determined approached Manning's theoretical value as the molecular weight of polyelectrolytes increased. Characteristic features of the electric properties of polyelectrolytes were reproduced. The anisotropy of the electrical polarizability of DNA in salt-free solution increased on dilution of the polymer concentration and was proportional to the second or higher power of the molecular weight consistent with experiment.
 

Colloidal and Molecular Electro-Optics

Division of Colloid and Surface Chemistry
The 225th ACS National Meeting, New Orleans, LA, March 23-27, 2003