We present an extensive computer simulation study of structure formation in amphiphilic block copolymer solutions after a quench from a homogeneous state. By using a mesoscopic field-based simulation method, we are able to access time scales in the range of a second. A "phase diagram" of final structures is mapped out as a function of the concentration and solvent philicity of the copolymers. A rich spectrum of structures is observed, ranging from spherical and rodlike micelles and vesicles to toroidal and net-cage micelles. The dynamical pathways leading to these structures are analyzed in detail, and possible ways to control the structures are discussed briefly.

Self-assembly of symmetric diblock copolymers in confined state has been investigated by means of Monte Carlo simulation method. The symmetric diblock copolymers were confined in two- (parallel walls or circle) or in three-dimensional (spherical or cylindrical) space. There are interactions between these boundaries and the symmetric diblock polymers. These interactions and boundary shape resulted in the formation of novel self-assemble structures, e.g., strip, circle, core-multishell, and multibarrel-layer structures. Simulation results predicated that it is possible to design different phase structures for block copolymers by adjusting boundary shape and boundary-block copolymer interactions.

We studied the dynamics of vesicle formation in an initially homogeneous dilute solution of amphiphilic diblock copolymers, using the external potential dynamics (EPD) method. The system was quenched into the unstable two-phase region inside the spinodal curve. We discovered a new pathway of spontaneous vesicle formation: First, spinodal decomposition sets in, and the fluid acquires a weakly modulated structure. After an incubation time, the composition fluctuations of this background pattern trigger the nucleation of spherical micelles. In a third step, copolymers from the solution slowly aggregate to the micelles; they grow and become semivesicles (bigger spherical micelles with a solventphilic core). Finally, solvent particles diffuse into the semivesicles, and they become full vesicles. We show that the solventphilic parts of the copolymers play a crucial role for the transition from semivesicles to vesicles. The different contributing mechanisms are discussed, and a simple method to control vesicle formation by using uniform sphere micelles as seeds is proposed.

We have used lattice Monte Carlo simulations to investigate the molecular assembly of symmetric diblock copolymer melts within cylindrical nanochannels. We studied the effect that the surface field has on the copolymer morphology in three cylinders having different diameters. Upon varying the strength of the surface field, we observed a variety of morphologies, including stacked-disk, single-helix, catenoid-cylinder, gyroidal, stacked-circle, and concentric cylindrical barrel structures. The results of these simulations should be helpful when designing polymeric nanomaterials confined in cylindrical nanochannels.

The complex microstructures assembled by amphiphilic diblock copolymer in dilute solution have been investigated by the application of real-space self-consistent field theory in two-dimensional space. Different micelles, such as spherelike micelles, rodlike micelles, and vesicles are produced. The simulations show that vesicles are metastable in dilute solution within a certain range of some parameters. The mechanism for the formation of micromorphologies, especial vesicles, is discussed.