  We investigate the effect of polymer length dispersity on the properties of
self-assembled micelles in solution by self-consistent field calculations.
Polydispersity stabilizes micelles by raising the free energy barriers of
micelle formation and dissolution. Most importantly, it significantly reduces
the size fluctuations of micelles: Block copolymers of moderate polydispersity
form more uniform particles than their monodisperse counterparts. We attribute
this to the fact that the packing of the solvophobic monomers in the core can
be optimized if the constituent polymers have different length.
