Reevaluation of Poly(ethylene-<i>alt</i>-propylene)-<i>block</i>-Polydimethylsiloxane Phase Behavior Uncovers Topological Close-Packing and Epitaxial Quasicrystal Growth

Reanalysis of an asymmetric poly(ethylene-alt-propylene)-block-polydimethylsiloxane (PEP-PDMS) diblock copolymer first investigated in 1999 has revealed a rich phase behavior including dodecagonal quasicrystal (DDQC), Frank–Kasper σ phase, and body-centered cubic (BCC) packing at high temperature adjacent to the disordered state. On subjecting sample large amplitude oscillatory shear well below σ-BCC order–order transition (TOOT), small-angle X-ray scattering evidenced emergence twinned BCC that, on heating, underwent unusually anisotropic DDQC Surprisingly, we observe no evidence this apparent epitaxy heating or cooling through equilibrium transition. We rationalize these results terms shear-induced BCC-DDQC favored by micelle translation-mediated ordering dynamics far TOOT.