Rapid and reliable processing methods for forming ordered block copolymer (BCP) materials with low defect density in a thin film geometry are required for many nanotechnology applications. Vertically aligned BCP structures, in particular, have applications ranging from nanolithography for electronics and photonics applications to nanoporous membranes for water remediation and novel batteries for flexible electronics. However, the attainment of a nearly complete vertical orientational order of the BCP-ordered phase remains challenging. Solvent-based techniques, such as direct immersion annealing (DIA) and solvent vapor annealing (SVA), have immense potential for these applications of BCP films, as it allows for a ‘tuning’ of their thermodynamic, structural, and chain mobility-driven kinetic properties. We first demonstrate that DIA, using a judicious choice of binary solvent mixtures, along with a relatively hydrophobic ionic liquid (IL), induces the rapid vertical ordering in polystyrene-b-poly(methyl methacrylate) (PS-PMMA) in lamellae-forming block copolymer films. The IL in a binary solvent mixture with toluene and heptane apparently gives rise to a near-neutral solvent for the BCP for itself and the boundary that is useful for attaining the vertical microstructure within the BCP film. Next, we show that an IL can moreover suppress the dewetting of the PS-PMMA films to achieve long-range order using SVA in cylindrical films after long annealing times. Both vertical and horizontal morphologies are attained in these films by selecting different solvent conditions. Attaining enhanced vertical and horizontal BCP structures with long-range defect-free order by tuning solvent quality and using additives like ILs can render them useful for many nanotech applications.

中文翻译：

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具有增强膜稳定性的嵌段共聚物膜中的溶剂处理和离子液体启用的长程垂直排序

许多纳米技术应用需要快速可靠的加工方法，以在薄膜几何形状中形成具有低缺陷密度的有序嵌段共聚物 (BCP) 材料。特别是垂直排列的 BCP 结构，其应用范围从用于电子和光子学应用的纳米光刻到用于水修复的纳米多孔膜和用于柔性电子的新型电池。然而，实现 BCP 有序相的几乎完整的垂直定向顺序仍然具有挑战性。基于溶剂的技术，如直接浸入退火 (DIA) 和溶剂蒸汽退火 (SVA)，对于 BCP 薄膜的这些应用具有巨大的潜力，因为它允许“调整”它们的热力学、结构和链迁移率驱动的动力学特性。我们首先证明 DIA，b-聚（甲基丙烯酸甲酯）（PS-PMMA）在形成薄片的嵌段共聚物薄膜中。IL 与甲苯和庚烷的二元溶剂混合物中的 IL 显然为 BCP 本身和用于获得 BCP 膜内垂直微结构的边界产生了接近中性的溶剂。接下来，我们表明 IL 还可以抑制 PS-PMMA 薄膜的去湿，从而在长时间退火后在圆柱形薄膜中使用 SVA 实现长程有序。通过选择不同的溶剂条件，在这些薄膜中获得了垂直和水平形态。通过调整溶剂质量和使用 IL 等添加剂来获得具有长程无缺陷顺序的增强型垂直和水平 BCP 结构，可以使它们适用于许多纳米技术应用。