PEG-based diblock and triblock copolymers bearing blocks of lipid-mimetic monomer units, 1,3-didodecyloxy2-glycidyl-glycerol (DDGG), were synthesized via anionic polymerization. They were characterized by H-1 nuclear magnetic resonance spectroscopy and gel permeation chromatography. The copolymers are of a higher poly(DDGG) to PEG ratio compared to related copolymers studied earlier. They self-associate both in aqueous (water) and nonaqueous (n-heptane) solutions. The self-assembled structures were studied by simultaneous dynamic and static light scattering. In both solvents nanoparticles with weight-average molecular weights reaching 390 x 10(6) were formed. Cryogenic transmission electron microscopy performed on aqueous dispersions revealed coexistence of unilamellar vesicles and fractions of multilamellar vesicles or vesicles with internal folded lamellar structures. On the basis of numerical calculations of the area per lipid anchor, formation of reversed vesicles and disks in heptane by the diblock and triblock copolymers, respectively, was suggested. The aggregates are able to solubilize large amounts Of Substances that are insoluble in the medium in which the aggregates are formed. At high heptane contents the close bilayer structure of the normal vesicles in water no longer exists. Upon the addition of water the dispersions of reverse vesicles or disks in heptane undergo transition from reverse bilayers to monolaver stabilized water-in-oil emulsions.