Block copolymers are chain molecules containing blocks of two or several chemically incompatible components. Much like smaller amphiphiles (e.g., lipids in water), copolymers in melt or solution spontaneously aggregate into a variety of nanostructures, e.g., lamellar phases or polymeric vesicles, which can be tuned by tuning system parameters such as the chain lengths, the block lengths, the composition, the temperature, etc. This can be used to prepare nanoscaled materials with well-defined properties. To simulate these processes on a mesoscopic scale, it is often efficient to use field-based methods where the polymers are no longer treated individually (as single chains). We will briefly introduce the concept of field-based polymer simulations and present two applications: The formation of a microemulsion in a ternary copolymer/homopolymer system [1,2] and the dynamics of spontaneous vesicle formation in a dilute copolymer solution [3,4]

1. D. Düchs, V. Ganesan, G. Fredrickson, F. Schmid, Fluctuation effects in ternary AB+A+B polymeric emulsions, Macromolecules 36, 9237 (2003).
2. D. Düchs, F. Schmid, Formation and structure of the microemulsion phase in ternary AB + A + B polymeric microemulsions, J. Chem. Phys. 121, 2798 (2004).
3. X. H. He, F. Schmid, Dynamics of spontaneous vesicle formation in dilute solutions of amphiphilic diblock copolymers, Macromolecules 39, 2654 (2006).
4. X. H. He, F. Schmid, in preparation (2006).