Statistics and Dynamics of Polymer Melt in Neutral Diblock Copolymer Single-Crystal Platelets

Polymer single-crystal (SC) platelets of poly(butylene oxide)-b-poly(lactic acid) (PBO-b-PLLA) of a well-defined shape, size, and grafting density have been fabricated and embedded into PBO melt for the study of the statistics and dynamics of the host polymers. The colloidal liquid-crystalline order of SCs above a threshold concentration of ∼2.2 vol % provides a confining environment for the molten PBO. Meanwhile, the peculiar type-A characteristics of PBO allow us to simultaneously probe the dielectric chain dimensions and the hierarchical dynamics of polymers under confinement. We observe negligible changes to the mean-square end-to-end distance of the polymer melt as well as the chain and segment dynamics, even the interlayer distance approaches the length scale comparable to the size of the host polymers. Our results provide direct evidence of the impacts of neutral walls on both the statistics and the dynamics of confined polymer melts, which can be also enlightening for the field of polymer nanocomposites.