The effect of shear flow on the formation and architecture of the multicompartment wormlike micelles of PS720-b-P2VP200-b-PEO375 (the subscripts indicate the numbers of the repeat units of the blocks) copolymer has been investigated by transmission electron microscopy (TEM) and field emission scanning electron microscopy (SEM).For a system with 1 wt% copolymer concentration and 13 wt% water concentration in THF/water

the micelle morphology observed by TEM changed from spheres to shuttlelike micelle aggregates

then to multicompartment wormlike micelles and finally to spheres as the stirring rate increased from 200 r/min to 2200 r/min.It was found that the micelles would change to worms again as the stirring rate changed from 200 r/min or 2200 r/min to 1500 r/min

indicating that the wormlike micelles were independent on initial phases.SEM observations revealed that the wormlike micelles were composed of overlapped disks

which was also confirmed by stain technology.Further research indicated that the formation of wormlike micelles underwent three stages.The triblock copolymer first self-assembled into small spheres

then these small spheres joined together to form intermediate shuttlelike structures and finally the spheres within the shuttlelike structures rearranged and underwent further adjustment to form the worms.Therefore

the multicompartment wormlike micelles formed as a result of secondary self-assembly of the spheres under shear flow.