Interaction cetyltrimethylammonium bromide-DNA investigated by dielectric spectroscopy

The dielectric data have been analyzed in terms of a single dielectric dispersion and discussed on the basis of a model involving the fluctuation of counter-ions along short segments of the DNA chains. Viscosity and surface tension measurements on DNA/CTAB solutions are also reported. The results show that CTAB binds as a single monomer to the DNA phosphate sites and that there is a release of one Na+ ion per CTAB bound to a phosphate site. Appreciable modification of the DNA conformation subsequent to the formation of the complex is also evidenced.