Process-directed self-assembly: Do we understand the collective short-time dynamics in multicomponent polymer melts?

Process-directed self-assembly refers to processes that reproducibly trap the kinetics of structure formation that ensues after a sudden change (“quench”) of the thermodynamic state into a desired, (meta)stable target state. This strategy benefits from specific advantages of copolymer systems, such as the rather comprehensive knowledge of equilibrium properties and the timescale separation between the quench of thermodynamic state variables, the spontaneous relaxation of the system towards the “nearest” metastable state, and the thermally activated escape from the metastable target state. Typically the relaxation from the unstable state occurs on a time scale that is comparable to the single-chain relaxation time. This short-time kinetics of structure evolution templates the morphology at later stages but poses challenges for a theoretical description. Examining simple, prototypical examples, we highlight the role of internal modes and indicate how dynamic SCFT can be generalized to include the consequences of the subdiffusive single-chain dynamics for the collective kinetics on times comparable to the Rouse-relaxation time.