Campbell Ian P, He Chunlin, Stoykovich Mark P
Department of Chemical and Biological Engineering, University of Colorado at Boulder, Boulder, Colorado 80309, United States.
ACS Macro Lett. 2013 Oct 15;2(10):918-923. doi: 10.1021/mz400269k. Epub 2013 Sep 27.
Solvent annealing produces ordered assemblies in thin films of block copolymers and, in contrast to uniform thermal annealing, can be used to tune the self-assembled morphology, control the domain orientation with respect to the substrate, and, as demonstrated here, reduce the defect density. The two-dimensional network topology of lamellae self-assembled by polystyrene--poly(methyl methacrylate) block copolymers in thin films was compared when processed by solvent and thermal annealing techniques. The mixed solvent annealing method described here reduced the overall defect density (e.g., dislocations with PMMA or PS cores) and thus the connectivity of the lamellar domains compared to thermal annealing; however, the long-range continuity of the networks was maintained and depended primarily on the copolymer composition. In addition, the persistence length of the lamellar domains for solvent annealed films was found to be 2-3 times that of the corresponding thermally annealed systems.
溶剂退火可在嵌段共聚物薄膜中产生有序组装体，与均匀热退火不同，它可用于调节自组装形态、控制相对于基底的畴取向，并且如本文所示，还可降低缺陷密度。比较了通过溶剂退火和热退火技术处理时，聚苯乙烯-聚（甲基丙烯酸甲酯）嵌段共聚物在薄膜中自组装形成的片层的二维网络拓扑结构。与热退火相比，本文所述的混合溶剂退火方法降低了整体缺陷密度（例如，具有聚甲基丙烯酸甲酯或聚苯乙烯核心的位错），从而降低了片层畴的连通性；然而，网络的长程连续性得以保持，且主要取决于共聚物组成。此外，发现溶剂退火薄膜的片层畴的持久长度是相应热退火体系的2至3倍。
