The Stabilized Induced Dipole in Solutions of Polynucleotides

Abstract

It has been found from electric birefringence measurements that in solutions of NaDNA and Na poly(A) orientation of solute molecules in an electric field is due to an induced dipole at low ionic strength, but a contribution of the permanent dipole to orientation becomes significant with increasing ionic strength. In solutions of intermediate ionic strength, the birefringence signals were of permanent dipole type under reversing pulses of low field intensities, but they were of induced dipole type at higher field intensities. These experimental results can be explained by supposing that the induced dipoles of the polyelectrolytes are stabilized by the dipole-ion interaction in the solutions of high ionic strength.