Substrate interaction effects on order to disorder transition behavior in block copolymer films

• Published in: Journal of polymer science. Part B, Polymer physics Polymer physics, 2013-04, Vol.51 (7), p.567-573
• Main Authors: Ahn, Hyungju, Lee, Yonghoon, Lee, Hoyeon, Kim, Yoonkeun, Ryu, Du Yeol, Lee, Byeongdu
• Format: Article
• Language: English
• Subjects: Amplification; Block copolymers; Blocking; Composition effects; Copolymers; Film thickness; Fluctuation; interaction parameter; interfaces; phase behavior; phase transition; Reproduction; SAXS; Solvents; thin films
• ISSN: 0887-6266; 1099-0488
• DOI: 10.1002/polb.23266

We present an overview of the recent progress on the phase transition in the block copolymer (BCP) films in terms of the interfacial interactions effects of the substrates and the χ (Flory‐Huggins segmental interaction parameter) effects between the two blocks. For the BCP films thinner than a critical thickness (Lc) above which the transition is independent of film thickness, the order‐to‐disorder transition (ODT) increased or decreased with decreasing film thickness depending on the interfacial interaction types. The rapid and slow changes in the ODT were attributed to the relative magnitude of enthalpic contribution to χ between two blocks. Interestingly, a periodic amplification in the block composition for the BCP films suppressed the compositional fluctuation in the film geometry, resulting in the ODT shifts from the bulk ODTs above Lc. This effect of the BCP films was more illustrated by the ODT shift effects depending on the strength of the preferential interactions on the substrates. © 2013 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2013 In this work, the order‐to‐disorder transition (ODT) in block copolymer (BCP) films is reviewed in terms of the interfacial interaction effects of the substrates and the χ effects between the two blocks. For the BCP films thicker than a critical thickness (Lc) above which the transition is independent of film thickness, a periodic amplification in the block composition for the BCP films suppressed the compositional fluctuation in the film geometry, resulting in the ODT shifts from the bulk ODTs.