Study of internal modes of a ‘‘living polymer’’ by transient electric birefringence

We use a pulsed electric field to study transient electric birefrigence in ``living polymers.'' The decay of birefringence is nonexponential and depends on the pulse width of the electric field. The relaxation is modeled in terms of the collective modes of the individual polymers with Zimm dynamics. Using this model, we find that the living polymer behaves as a flexible chain even at very low concentrations. Two distinct growth regimes are found for the polymer contour length L{} as a function of surfactant concentration {φ}. In the very dilute regime L{} increases as {}{φ} , and levels off at higher concentrations.