Epitaxy-Directed Self-Assembly of Copolymers and Polymer Blends

Directed self-assembly of materials into patterned structures is of great importance since the performance of them depends remarkably on their multiscale hierarchical structures. Therefore, purposeful structural regulation at different length scales through crystallization engineering provides an opportunity to modify the properties of polymeric materials. Here, an epitaxy-directed self-assembly strategy for regulating the pattern structures including phase structure as well as crystal modification and orientation of each component for both copolymers and polymer blends is reported. Owing to the specific crystallography registration between the depositing crystalline polymers and the underlying crystalline substrate, not only order phase structure with controlled size at nanometer scale but also the crystal structure and chain orientation of each component within the separated phases for both copolymers and polymer blend systems can be precisely regulated. The epitaxy-directed autonomous self-assembly of alternatively arranged and alternatively distributed PCL and PEG edge-on lamellar structures with temperature-controlled domain size in ultrathin films of PCL-b-PEG diblock copolymers on highly oriented PE and iPP substrates, respectively, is reported. The arrows show the molecular chain directions of melt-drawn oriented PE and iPP substrate films.image