DIELECTRIC-RELAXATION OF COLLAGEN IN AQUEOUS-SOLUTIONS

The complex dielectric constant of collagen in aqueous solutions (polymer concentration, Cp = 0.02–0.2%) was measured at 10°C in the frequency range from 3 Hz to 30 kHz. The loss peak for Cp = 0.02% is located at 90 Hz and the dielectric relaxation time τD is estimated to be 1.8 ± 0.3 msec. The τD agrees well with the rotational relaxation time estimated from the reduced viscosity, and the relaxation is ascribed to the end‐over‐end rotation of the molecule. The Cp dependence of τD and the dielectric increment Δε are interpreted in terms of the aggregation of molecules. The dipole moment of a molecule, obtained from Δε at Cp = 0.02% and pH 6.5, is (5.2 ± 0.2) × 104D, which is explained by the asymmetrical distribution of the ionized side chains of the molecule. Copyright © 1979 John Wiley & Sons, Inc.