Power-law-like stress relaxation of block copolymers. Disentanglement regimes

摘要: We consider stress relaxation in a strongly segregated lamellar mesophase, where block copolymers are the "brush" state with junction points confined to interface between adjacent lamellae and blocks stretched out away from it. If molecular weight of is large enough, they entangle their neighbors as well opposite brush. The number entanglements one particular chain brush varies even monodisperse system. demonstrate that this dispersion leads very broad spectrum times an effectively power-law-like function log G - (log t)" CY = 1/2 (a 2) strong (weak) chain-stretching limit. analyze various disentanglement mechanisms for diblocks triblocks onset diffusion along interface. Another mechanism due displacement across into "enemy" phase. conclude highly entangled it will be important mode (especially triblock copolymers). For asymptotically long perfectly ordered lamella liquidlike. In system defects domain structure controlled by processes equilibration excess density layers. mesophase we found G(t) t 4. 2, while cylindrical