Gelation of micellar block polyelectrolytes: Evidence of glassy behavior in an attractive system

We present small-angle neutron Scattering and theology for micellar solutions of polystyrene-poly-(acrylic acid) block copolymers that can be regarded as attractive colloids. These systems form gels at high effective micellar volume fractions (φ > 0.64) that are suggestive of disordered colloidal glasses. At the gel point, the solution rheology follows the scaling predicted by classical percolation theory, with G′ G″ ∼ ω^Delta;. We argue that this scaling could be due either to formation of a percolated network or to a pretransitional glassy phase.