Crystallization-Driven Co-Assembly of Micrometric Polymer Hybrid Single Crystals and Nanometric Crystalline Micelles

In the present work, crystallization-driven coassembly of micrometric polymer single crystals and nanometric block copolymer micelles was achieved. The hybrid single crystals are first formed by cocrystallization of polyethylene (PE) homopolymer and polyethylene-<i>b</i>-poly­(<i>tert</i>-butyl acrylate) (PE-<i>b</i>-P<i>t</i>BA) block copolymer (BCP) in DMF or DMF/<i>o</i>-xylene mixed solvent. The morphology of the obtained hybrid single crystals can be regulated via changing the solvent composition, crystallization temperature and mass ratio of BCP/homopolymer. Because of the difference in crystallization rate, the distribution of PE-<i>b</i>-P<i>t</i>BA BCP in the hybrid single crystals may be inhomogeneous, leading to a concave gradient surface structure. The hybrid single crystals have a double-layer structure, in which PE homopolymer chains adopt extended conformation and the PE blocks in PE-<i>b</i>-P<i>t</i>BA are probably once-folded. After the PE homopolymer is consumed, cylindrical micelles of PE-<i>b</i>-P<i>t</i>BA can further epitaxially grow on the lateral surface of the hybrid single crystals and “ciliate paramecium-like” coassemblies are yielded. The single crystal/micelles coassemblies can be prepared either by one-step method, in which PE and PE-<i>b</i>-P<i>t</i>BA are added together in a single step, or by two-step method, in which the hybrid single crystals are prepared in the first step and extra PE-<i>b</i>-P<i>t</i>BA is added in the second step to grow BCP micelles. This work provided a simple route to construct hierarchical assemblies composed of objects with different scales by using crystallization as the key driving force

Specific Disassembly of Lamellar Crystalline Micelles of Block Copolymer into Cylinders

Specific Disassembly of Lamellar Crystalline Micelles of Block Copolymer into Cylinder