Polyelectrolyte Molecule in an Elongational Flow

The theory describing the stretching of a weakly charged polyelectrolyte molecule by elongational shear flow is developed. It is shown that for a polyelectrolyte immersed in a salt-added solution two critical values of shear flow gradient exist: the lower critical point corresponds to the chain stretching on the scale of superblobs of size equal to the Debye screening length and the upper critical point corresponds to the complete stretching of the chain on the scale of monomer units.