  The shear flow of a triblock copolymer micellar solution (PEO--PPO--PEO
Pluronic P84 in brine) is investigated using simultaneous rheological and
velocity profile measurements in the concentric cylinder geometry. We focus on
two different temperatures below and above the transition temperature $T_c$
which was previously associated with the apparition of a stress plateau in the
flow curve. (i) At $T=37.0^\circ$C $<T_c$, the bulk flow remains homogeneous
and Newtonian-like, although significant wall slip is measured at the rotor
that can be linked to an inflexion point in the flow curve. (ii) At
$T=39.4^\circ$C $>T_c$, the stress plateau is shown to correspond to stationary
shear-banded states characterized by two high shear rate bands close to the
walls and a very weakly sheared central band, together with large slip
velocities at the rotor. In both cases, the high shear branch of the flow curve
is characterized by flow instability. Interpretations of wall slip, three-band
structure, and instability are proposed in light of recent theoretical models
and experiments.
