Dielectric Studies of Electrolytic Poly-α-Amino Acids in Aqueous Solutions

Abstract

Dielectric dispersions of poly-L-lysine and its various salts in aqueous solutions were measured in a frequency range 1 kHz∼3 MHz. The dispersion curve was found to have a single midpoint frequency for helical poly-L-lysine. The electric dipole moment was proportional to its molecular weight and was 4.0 Debyes per lysine residue. The value of limiting relaxation time and its dependence on the molecular weight were discussed to know whether they indicated that the dielectric dispersion was due to rotational motion of electric dipole on the molecule or not. On the other hand, the dispersions of its salts were almost found to be appoximated by Debye's curves of separated two relaxation times. From the value of limiting relaxation time in the lower frequency region and its dependence on molecular weight, the dielectric dispersions of salts might be considered to be due to movement of counter-ions. Also, the dielectric dispersions of these salts in the frequency region higher than 100 kHz were explained by Max...