Directed Self-Assembly of Symmetric Block Copolymers in Thin Films on Soft Grating Patterns
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초록
내용
In this study, we present an intuitive and effective method to induce directed self-assembly (DSA) of symmetric block copolymers (BCPs) using soft grating patterns. By physically rubbing poly(tetrafluoro ethylene) (PTFE), the horizontally aligned PTFE grating patterns are produced on Si wafer due to its low friction coefficient and high wear rate. Then thin films of polystyrene-block-poly(methyl methacrylate) copolymers (PS-b-PMMA) form on the patterned substrates as spin-coated on nano-stripes and solvent-annealed in vapor of organic solvents to induce self-assembly of block copolymer. The parallel orientation of lamellar is generated after solvent-annealing process. Interestingly, it is observed that lamellar nanostructures are aligned along the grating patterns and their ordering behavior are improved by the grating patterns. These well-ordered BCP nanostructures were utilized as templates to synthesize inorganic nanowires for further applications.