VISCOELASTIC PROPERTIES OF ENTANGLED DNA SOLUTIONS

Viscoelastic properties of double-stranded DNA (bacteriophage T2 DNA) were measured in semi-dilute high-salt aqueous solutions in a concentr ation range from 0.16 to 1.6 mg/cm(3). The viscoelastic properties fol low the same universal behaviour as synthetic linear polymers. The red uced variables for the concentration dependence of the viscosity are e ta/eta(Rouse) and C/C-e, where eta(Rouse) is the Viscosity in a Rouse regime and C-e the concentration at which DNA starts to be entangled. The concentration C-e differs from the overlap concentration C becaus e n(e) blobs are needed for the chains to be entangled. For phage T2 D NA, the concentration C-e is equal to 0.25 mg/cm(3.)