Altinpinar Sedakat, Zhao Hui, Ali Wael, Kappes Ralf S, Schuchardt Patrick, Salehi Sahar, Santoro Gonzalo, Theato Patrick, Roth Stephan V, Gutmann Jochen S
†Institute for Physical Chemistry, University of Duisburg-Essen, Universitätsstrasse 2, 45141 Essen, Germany.
§Deutsches Textilforschungszentrum Nord-West gGmbH, Adlerstraße 1, 47798 Krefeld, Germany.
Langmuir. 2015 Aug 18;31(32):8947-52. doi: 10.1021/acs.langmuir.5b00750. Epub 2015 Aug 6.
Highly ordered block copolymer thin films have been studied extensively during the last years because they afford versatile self-assembled morphologies via a bottom-up approach. They promise to be used in applications such as polymeric membranes or templates for nanostructured materials. Among the block copolymer structures, perpendicular cylinders have received strong attention due to their ability to fabricate highly ordered nanopores and nanowires. Nanopores can be created from a thin block copolymer film upon the removal of one block by selective etching or by dissolution of one polymer block. Here we demonstrate the utilization of polystyrene-block-poly(ethylene oxide) diblock copolymer (PS-hν-PEO) with an ortho-nitrobenzyl ester (ONB) as the photocleavable block-linker to create highly ordered thin films. Removal of the PEO block by choosing an appropriate solvent upon photocleavage is expected to yield arrays of nanopores decorated with functional groups, thus lending itself to adsorption or filtration uses. While the feasibility of this approach has been demonstrated, it is crucial to understand the influence of removal conditions (i.e., efficiency of photocleavage as well as best washing solvent) and to evaluate changes in the surface topology and inner structure upon photocleavage. To this end, the time dependence evolution of the surface morphology of block copolymer thin films was studied using grazing-incidence small-angle X-ray scattering (GISAXS) technique in combination with scanning probe microscopy.
在过去几年中,高度有序的嵌段共聚物薄膜得到了广泛研究,因为它们通过自下而上的方法提供了多种自组装形态。它们有望用于诸如聚合物膜或纳米结构材料模板等应用中。在嵌段共聚物结构中,垂直圆柱由于能够制造高度有序的纳米孔和纳米线而受到了强烈关注。通过选择性蚀刻去除一个嵌段或通过溶解一种聚合物嵌段,可以从薄的嵌段共聚物薄膜中产生纳米孔。在这里,我们展示了利用带有邻硝基苄酯(ONB)作为光可裂解嵌段连接基的聚苯乙烯-嵌段-聚环氧乙烷二嵌段共聚物(PS-hν-PEO)来制备高度有序的薄膜。通过光裂解后选择合适的溶剂去除PEO嵌段,有望产生装饰有官能团的纳米孔阵列,从而适用于吸附或过滤用途。虽然这种方法的可行性已经得到证明,但了解去除条件(即光裂解效率以及最佳洗涤溶剂)的影响并评估光裂解后表面拓扑结构和内部结构的变化至关重要。为此,结合扫描探针显微镜,使用掠入射小角X射线散射(GISAXS)技术研究了嵌段共聚物薄膜表面形态随时间的演变。