We report on the use of a selective, non-volatile ionic liquid (IL) to enhance the self-assembly via solvent annealing of a low molecular weight block copolymer (BCP) of styrene and 2-vinylpyridine (2VP) suitable for generating sub-10 nm features. Diblock and triblock copolymers of different molecular weights of styrene and 2VP are individually blended with the IL and then solvent annealed in acetone, a non-preferential solvent for the BCPs. Differential scanning calorimetry indicates that the IL selectively resides in the 2VP block of the BCP, resulting in a decrease of the block's T_g and an increase of the effective Flory–Huggins parameter (χ_eff) of the BCP. The influence of the IL on the non-preferential window of a random copolymer brush used to treat the substrate for self-assembly of the BCPs is also analyzed. Well-defined lamellar patterns form when the optimal weight ratio of IL (∼1%) is added to the BCPs. A detailed analysis of the orientational correlation length and pitch size of the BCPs quantitatively shows that the addition of the IL enhanced the microphase separation of the low molecular weight version of the BCP. Subsequent treatment of the self-assembled BCP with sequential infiltration synthesis yields sub-10 nm AlO_x lines.

中文翻译：

---

通过添加离子液体，增强了低分子量嵌段共聚物薄膜的微相分离。

我们报告了使用选择性非挥发性离子液体（IL）通过溶剂退火苯乙烯和2-乙烯基吡啶（2VP）的低分子量嵌段共聚物（BCP）来增强自组装的可能性，该低分子量嵌段共聚物适合于产生亚- 10纳米功能。将不同分子量的苯乙烯和2VP的二嵌段和三嵌段共聚物分别与IL混合，然后将溶剂在BCP的非优先溶剂丙酮中退火。差示扫描量热表明IL选择性驻留在BCP的2VP块，导致的块的下降Ť_克和增加了有效的Flory-Huggins参数的（χ _EFF）。还分析了IL对用于处理BCP自组装基材的无规共聚物刷的非优选窗口的影响。当将最佳的IL（〜1％）重量比添加到BCP时，会形成清晰的层状图案。对BCP的取向相关长度和间距大小的详细分析定量显示，IL的添加增强了BCP低分子量形式的微相分离。用顺序渗透合成法对自组装BCP的后续处理产生了低于10 nm的AlO _x谱线。