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We report the synthesis and temperature-dependent morphologies of a series of polylactide-block-poly (ε-decalactone)-block-polylactide (LDL) triblock copolymers with 𝑀𝑛=16.0–18.1⁢kg/mol and volume fractions 𝑓L=0.27–0.31 and associated core-shell bottlebrush (csBB) polymers, which derive from enchaining LDL triblocks through a polymerizable midchain functionality. While the LDL triblocks form micellar Frank-Kasper A15 and σ phases due to the conformational asymmetry of this monomer pair, the csBB morphologies sensitively depend on the backbone degree of polymerization (𝑁bb). At low 𝑁bb values, micellar Frank-Kasper phases with the brush backbone situated in the matrix domain are stable, albeit with a modest reduction in the mean interfacial curvature evidenced by a σ to A15 order-to-order transition. However, larger 𝑁bb values drive csBBs to form hexagonally packed cylinders phases. This 𝑁bb-dependent phase behavior is rationalized in terms of a star-to-bottlebrush transition. At low 𝑁bb values, the csBBs are akin to star polymers with pointlike junctions that can support complex micelle packings. As 𝑁bb increases, the csBBs adopt cylindrical molecular geometries with extended backbones situated in the matrix domain that prefer hexagonally packed cylinders morphologies. 

Temperature-dependent X-ray photon correlation spectroscopy (XPCS) measurements are reported for a binary diblock copolymer blend that self-assembles into an aperiodic dodecagonal quasicrystal (DDQC) and a periodic Frank-Kasper σ phase approximant. The measured structural relaxation times are Bragg scattering wavevector-independent and are five times faster in the DDQC than the σ phase, with minimal temperature dependence. The underlying dynamical relaxations are ascribed to differences in particle motion at the grain boundaries within each of these tetrahedrally close-packed assemblies. These results identify unprecedented particle dynamics measurements of tetrahedrally-coordinated micellar block polymers, thus expanding the application of XPCS to ordered soft materials.