Do We Understand the Collective Short-Time Dynamics in Multicomponent Polymer Melts?

Phase separation in multicomponent polymer melts is a ubiquitous process in polymer engineering and consequently has also attracted abiding interest from simulation and theory. Whereas the equilibrium thermodynamics of macrophase separation and microphase separation in homopolymer blends and copolymers can be rather quantitatively described by Self-Consistent Field Theory (SCFT) or extensions that capture fluctuations, the kinetics of structure evolution poses challenges for a theoretical description. Examining simple, prototypical examples, we highlight the role of internal modes and indicate how Dynamic Self-Consistent Field Theory (D-SCFT) can be generalised to include the consequences of the subdiffusive single-chain dynamics for the collective kinetics on times comparable to the Rouse-relaxation time