On the basis of the two-state model of a polyelectrolyte solution, the ion concentration in the polymer domain has been calculated by using the spherical Poisson-Boltzmann equation. The ion accumulation in the neighboring of the polyion influences, on different time scales, various electrical properties of the solution, in particular the low-frequency electrical conductivity and the high-frequency dielectric dispersion. These predictions have been compared with recent dielectric measurements on poly(L-glutamic acid) aqueous solutions during the conformational transition from the alpha-helix to random coil, and a satisfactory agreement has been found. This finding suggests that counterion distribution plays a different role in determining the electrical properties of charged polymer solutions, causing a electrophoretic contribution of the polymer domain to the electrical conductivity and influencing the high-frequency dielectric dispersion.
EFFECT OF COUNTERION CONCENTRATION ON THE DIELECTRIC BEHAVIOR OF A POLYPEPTIDIC CHAIN IN THE HELIX-COIL TRANSITION / Bordi, Federico; Cametti, Cesare; G., Paradossi. - In: BIOPOLYMERS. - ISSN 0006-3525. - 33:7(1993), pp. 1029-1035. (Intervento presentato al convegno 3RD NAPLES WORKSHOP ON CONFORMATIONAL ANALYSIS OF PEPTIDES : RELATIONSHIPS AND INTERACTIONS tenutosi a CAPRI, ITALY nel MAY 24-27, 1992) [10.1002/bip.360330705].
EFFECT OF COUNTERION CONCENTRATION ON THE DIELECTRIC BEHAVIOR OF A POLYPEPTIDIC CHAIN IN THE HELIX-COIL TRANSITION
BORDI, FEDERICO;CAMETTI, Cesare;
1993
Abstract
On the basis of the two-state model of a polyelectrolyte solution, the ion concentration in the polymer domain has been calculated by using the spherical Poisson-Boltzmann equation. The ion accumulation in the neighboring of the polyion influences, on different time scales, various electrical properties of the solution, in particular the low-frequency electrical conductivity and the high-frequency dielectric dispersion. These predictions have been compared with recent dielectric measurements on poly(L-glutamic acid) aqueous solutions during the conformational transition from the alpha-helix to random coil, and a satisfactory agreement has been found. This finding suggests that counterion distribution plays a different role in determining the electrical properties of charged polymer solutions, causing a electrophoretic contribution of the polymer domain to the electrical conductivity and influencing the high-frequency dielectric dispersion.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
