Latent Alignment in Pathway-Dependent Ordering of Block Copolymer Thin Films

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• 作者：Pawel W. Majewski ; Kevin G. Yager
• 刊名：Nano Letters
• 出版年：2015
• 出版时间：August 12, 2015
• 年：2015
• 卷：15
• 期：8
• 页码：5221-5228
• 全文大小：651K
• ISSN：1530-6992

文摘

Block copolymers spontaneously form well-defined nanoscale morphologies during thermal annealing. Yet, the structures one obtains can be influenced by nonequilibrium effects, including processing history or pathway-dependent assembly. Here, we explore various pathways for ordering of block copolymer thin films, using oven-annealing, as well as newly disclosed methods for rapid photothermal annealing and photothermal shearing. We report the discovery of an efficient pathway for ordering self-assembled films: ultrarapid shearing of as-cast films induces 鈥渓atent alignment鈥?in the disordered morphology. Subsequent thermal processing can then develop this directly into a uniaxially aligned morphology with low defect density. This deeper understanding of pathway-dependence may have broad implications in self-assembly.