title: Screening and fundamental length scales in semidilute Na-DNA aqueous solutions.
abstract: The fundamental length scales in semidilute Na-DNA aqueous solutions have been investigated by dielectric spectroscopy. The low- and the high-frequency relaxation modes are studied in detail. The length scale of the high-frequency relaxation mode at high DNA concentrations can be identified with the de Gennes-Pfeuty-Dobrynin correlation length of polyelectrolytes in semidilute solution, whereas at low DNA concentrations and in the low added salt limit the length scale shows an unusual exponent reminiscent of semidilute polyelectrolyte chains with hydrophobic backbone. The length scale of the low-frequency relaxation mode corresponds to a Gaussian chain composed of correlation blobs in the low added salt limit, and to the Odijk-Skolnick-Fixman value of the single chain persistence length in the high added salt limit.
authors.affiliation: Institut za fiziku, 10000 Zagreb, Croatia. stomic@ifs.hr
authors.forename: S
authors.initials: S
authors.lastname: Tomić
authors.forename: T
authors.initials: T
authors.lastname: Vuletić
authors.forename: S Dolanski
authors.initials: SD
authors.lastname: Babić
authors.forename: S
authors.initials: S
authors.lastname: Krca
authors.forename: D
authors.initials: D
authors.lastname: Ivanković
authors.forename: L
authors.initials: L
authors.lastname: Griparić
authors.forename: R
authors.initials: R
authors.lastname: Podgornik
mesh_terms: D004247:DNA / Q000737:chemistry*; D004563:Electrochemistry; D011108:Polymers; D012964:Sodium / Q000737:chemistry*; D012996:Solutions; D014867:Water
chemical_list: D011108:Polymers; D012996:Solutions; D014867:Water; D004247:DNA; D012964:Sodium