Tunable morphologies in charged multiblock polymers in thin film geometry

该研究项目研究了ABCBA类型的多嵌段聚合物在薄膜几何结构中形成的形态。在这里，将研究一种以疏水的聚甲基丙烯酸甲酯(PMMA)末端嵌段A、聚(2-二甲氨基)甲基丙烯酸乙酯(PDMAEMA)和聚(2-乙烯基吡啶)(P2VP)中间嵌段B和C为特征的五嵌段三元共聚物。PDMAEMA和P2VP嵌段的荷电状态可以由制备薄膜所用溶液的pH值控制，并且对薄膜的结构有很大的影响。该项目的目的是使用选择性溶剂(水、甲醇)的循环蒸气处理来安装多种形貌，这些形貌是嵌段之间的相互作用和纳米结构域桥接的结果。从不同pH值的水溶液中通过旋涂的方法制备了薄膜。通过吸收溶剂，端块的流动性以及中间块的灵活性将发生改变，这可能会导致平衡状态，并使不同的块能够混合。还将使用光学显微镜、原子力显微镜和掠入射小角X射线散射(GISAXS)原位研究薄膜的形貌。GISAXS数据的建模将不仅使用薄膜内部的结构，还将使用来自表面地形的贡献。选定的样品将使用掠入射共振软X射线散射进行研究，也将在溶剂蒸汽处理期间进行，以区分化学上不同的纳米结构域。为了阐明电荷顺序分布在五嵌段共聚物中的作用，将对参考样品PMMA-b-PDMAEMA-b-PMMA进行单次测量。复杂聚合物、用于结构研究的先进原位方法和定量建模的独特组合将使人们能够全面了解带电荷嵌段的多嵌段聚合物的行为以及构建薄膜的可能性。

The research project addresses the morphologies formed by multiblock polymers of the type ABCBA in thin film geometry. At this, a pentablock terpolymer featuring hydrophobic poly(methyl methacrylate) (PMMA) end blocks A together with poly(2-(dimethylamino)ethyl methacrylat) (PDMAEMA) and poly(2-vinylpyridine) (P2VP) middle blocks B and C will be investigated. The charge state of the PDMAEMA and P2VP blocks can be controlled by the pH value of the solution used for preparation of the films and has a strong influence on the structures in the film. Aim of the project is to use cyclic vapor treatment with selective solvents (water, methanol) to install a multitude of morphologies, which are a result of the interplay between the interactions between the blocks and the bridging of the nanodomains. The films are prepared by spin-coating from aqueous solution having different pH values. By taking up solvent, the mobility of the end blocks as well as the flexibility of the middle blocks will be altered, which possibly results in equilibrium states and enables the mixing of different blocks. The film morphologies will be investigated, also in situ, using optical microscopy, atomic force microscopy and grazing-incidence small-angle X-ray scattering (GISAXS). Modeling of the GISAXS data will be carried out using not only structures inside the film, but also contributions from the surface topography. Selected sample will be investigated using grazing-incidence resonant soft X-ray scattering, also during solvent vapor treatment, to discriminate the chemically different nanodomains. To elucidate the role of the sequential distribution of charges in the pentablock terpolymer, single measurements will be carried out on a reference sample PMMA-b-PDMAEMA-b-PMMA. The unique combination of a complex polymer, advanced in-situ methods for structural investigations and quantitative modeling will provide comprehensive insight into the behavior of multiblock polymers with charged blocks and the possibilities for structuring thin films.