DISORDER-ORDER TRANSITIONS IN SOFT-SPHERE POLYMER MICELLES

Diblock copolymers in a selective solvent often assemble into spherica l micelles. These micelles demonstrate long range order at moderate po lymer concentrations. We explore the nature of the disorder-order tran sition in micellar suspensions through small angle x-ray diffraction s tudies. The phase behavior includes body-centered cubic (bcc) and face -centered cubic (fcc) lattices. We present the first phase diagram for block copolymer micelles to include both bcc and fcc structures and c haracterize the lattice selection by a ratio of coronal layer thicknes s to core radius.