Rheology of semi-dilute solutions of calf-thymus DNA

Abstract

We study the rheology of semi-dilute solutions of the sodium salt of calf-thymus DNA in the linear and nonlinear regimes. The frequency response data can be fitted very well to the hybrid model with two dominant relaxation times $\tau_{\circ}$ and $\tau_{1}$. The ratio $\frac{\tau_{\circ}}{\tau_{1}} \sim$ 5 is seen to be fairly constant on changing the temperature from 20$^{\circ}$C to 30$^{\circ}$C. The shear rate dependence of viscosity can be fitted to the Carreau model.