Yu Jian-Yuan, Landis Stefan, Fontaine Philippe, Daillant Jean, Guenoun Patrick
Université Paris-Saclay, CEA, CNRS, NIMBE, Lions, 91191, Gif-sur-Yvette, France.
CEA, LETI, Minatec, 17 Rue des Martyrs, F-38054, Grenoble Cedex 9, France.
Soft Matter. 2020 Sep 16;16(35):8179-8186. doi: 10.1039/d0sm00603c.
Building 3D ordered nanostructures by copolymer deposition on a substrate implies a full control beyond the thin film regime. We have used here block copolymers (BCPs) forming bulk lamellar phases to form thick, i.e. much thicker than the lamellar period, structured films on a substrate. Films are formed by a simple method of multiple successive coatings. The film structure is controlled using the combined action of surface templating and annealing time. Sections of the thick layers were characterized by scanning electron microscopy (SEM) after etching of one of the BCP moieties. We show that perfect hexagonally perforated films (HPL) with lamellae parallel to the substrate are formed for a wide thickness range up to 300 nm. Grazing incidence small angle X-ray scattering (GISAXS) confirms such an organization by revealing that perforations sit on a hexagonal lattice. A lamellar organization perpendicular to the substrate is shown to take over for thicker films. A scenario consistent with our observations is proposed, where the sequence of phases results from the balance between surface and stretching energy effects.
通过在基底上共聚物沉积构建三维有序纳米结构意味着要全面控制超出薄膜状态的情况。我们在此使用形成本体层状相的嵌段共聚物（BCP）在基底上形成厚的（即比层周期厚得多）结构化薄膜。薄膜通过多次连续涂覆的简单方法形成。利用表面模板化和退火时间的联合作用来控制薄膜结构。在蚀刻掉其中一个BCP部分后，通过扫描电子显微镜（SEM）对厚层的截面进行表征。我们表明，对于厚度高达300 nm的宽范围，形成了具有平行于基底的片层的完美六边形穿孔薄膜（HPL）。掠入射小角X射线散射（GISAXS）通过揭示穿孔位于六边形晶格上证实了这种结构。对于更厚的薄膜，显示出垂直于基底的层状结构。提出了一种与我们的观察结果一致的情况，其中相的序列源于表面能和拉伸能效应之间的平衡。
