Lee Sangho, Cheng Li-Chen, Gadelrab Karim R, Ntetsikas Konstantinos, Moschovas Dimitrios, Yager Kevin G, Avgeropoulos Apostolos, Alexander-Katz Alfredo, Ross Caroline A
Department of Materials Science and Engineering , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States.
Department of Materials Science Engineering , University of Ioannina , University Campus-Dourouti , 45110 Ioannina , Greece.
ACS Nano. 2018 Jun 26;12(6):6193-6202. doi: 10.1021/acsnano.8b02851. Epub 2018 Jun 8.
A combined experimental and self-consistent-field theoretical (SCFT) investigation of the phase behavior of poly(stryrene- b-dimethylsiloxane- b-styrene) (PS- b-PDMS- b-PS, or SDS32) thin films during solvent vapor annealing is presented. The morphology of the triblock copolymer is described as a function of the as-cast film thickness and the ratio of two different solvent vapors, toluene and heptane. SDS32 formed terraced bilayer morphologies even when the film thickness was much lower than the commensurate thickness. The morphology transitioned between bilayer cylinders, bilayer perforated lamellae, and bilayer lamellae, including mixed structures such as a perforated lamella on top of a layer of in-plane cylinders, as the heptane fraction during solvent annealing increased. SCFT modeling showed the same morphological trends as a function of the block volume fraction. In comparison with diblock PS- b-PDMS with the same molecular weight, the SDS32 offers a simple route to produce a diversity of well-ordered bilayer structures with smaller feature sizes, including the formation of bilayer perforated lamellae over a large process window.
本文介绍了一项关于聚（苯乙烯- b-二甲基硅氧烷- b-苯乙烯）（PS- b-PDMS- b-PS，或SDS32）薄膜在溶剂蒸汽退火过程中相行为的联合实验和自洽场理论（SCFT）研究。三嵌段共聚物的形态被描述为铸膜厚度以及两种不同溶剂蒸汽（甲苯和庚烷）比例的函数。即使膜厚度远低于相应厚度，SDS32仍形成了阶梯状双层形态。随着溶剂退火过程中庚烷分数的增加，形态在双层圆柱体、双层穿孔片层和双层片层之间转变，包括诸如在平面内圆柱体层之上的穿孔片层等混合结构。SCFT建模显示了作为嵌段体积分数函数的相同形态趋势。与具有相同分子量的双嵌段PS- b-PDMS相比，SDS32提供了一种简单的途径来产生具有更小特征尺寸的多种有序双层结构，包括在较大的工艺窗口内形成双层穿孔片层。
