| 학회 | 한국고분자학회 |
| 학술대회 | 2002년 가을 (10/11 ~ 10/12, 군산대학교) |
| 권호 | 27권 2호, p.14 |
| 발표분야 | 특별 심포지엄 |
| 제목 | Surface Topography in Block Copolymer Thin Films |
| 초록 | It is well known that symmetric diblock copolymers form lamellar microdomains on the order of their radii of gyration due to the constraint of chemical junction points between the two polymer blocks limited to the interface. When spun cast into thin films, the lamellae preferably align parallel to the substrate with symmetric or asymmetric wetting depending on the interplay between the substrate interaction and the surface tension of each block. This further causes the formation of island or hole structures with their heights quantized in (n + 1/2) L0 for the asymmetric wetting or in nL0 for the symmetric wetting since the block copolymer lamellae tend to maintain their equilibrium lamellar period L0. Up until now, only islands or holes have been observed in block copolymer thin films, which are thermodynamically stable structures. In present study, however, we first report the hierarchical surface topography in block copolymer thin films, which is a kinetically trapped metastable structure induced by the residual solvent. In PS-b-P2VP thin film, various herarchical surface topography such as island and fractal hole, hole-in-hole, and island-on-island were observed depending on the initial film thickness. The hole structure adjacent to the bottom brush layer was found to be always fractal, which is related to the autophobic dewetting between the brush layer tightly attatched to the substrate and the layer above. In PS-b-PMMA thin film, hole-in-hole structure was also observed, but the fractal hole was not obtained. The mechanism of hierarachical surface topography was inferred by considering the amount of residual solvent in block copolymer thin films, the interaction between solvent and block copolymer, the molecular weight of block copolymer, and the chain conformation of brush layer. Optical (OM) and atomic force microscopies (AFM) were employed to investigate the intriguing complex thin film morphology of block copolymers originating from the competition between the lamellar ordering and the slow evaporation of the residual solvent during the annealing process. |
| 저자 | 차국헌 |
| 소속 | 서울대 |
| 키워드 | |
| VOD | VOD 보기 |
