Heuristic correlation of rheological measurements and Electrochemical Impedance Spectroscopy (EIS) of the DN A/water system

In this work, it is reported viscosity, density, sound velocity and electrochemical impedance spectroscopy (EIS) measurements of calf thymus DNA in aqueous solutions, in order to investigate the overlapping C* and entanglement concentrations C_e. These critical concentrations demark the conditions at which start appearing interactions and entanglements between DNA molecules in solution. EIS has been proposed as new alternative analytical techniques to obtain C* and C_e in polyelectrolyte solutions. A new parameter the characteristic time (τ_c) was defined, and it is obtained from a new type of log-log Bode plot using the crossover frequency (τ_c=1/ω_c) of the real (Z') and imaginary (Z″) components when they are plotted as a function of the frequency. Preliminary results show similar values C* and C_e by EIS to those obtained from rheological, densimetry and sound velocity measurements.