Supramolecular Ion Conducting Membranes

我们将通过定向自组装来开发离子选择膜，其中离子通道由超分子络合物形成。以前，我们已经证明了带有焦点亲水磺酸头部基团的楔形两亲性π堆积分子可以自组装成超分子柱，在超分子柱中，磺酸基团堆积形成定义良好的离子通道。宽度和通过这些离子通道的流量可以由组装分子的分子结构控制。柱状通道将在垂直于所得膜表面的取向后通过与聚合物基质的交联和互连来共价稳定。这些膜将通过定向薄膜的光聚合或热聚合来制备。楔形分子的化学结构将通过温度依赖的X射线散射绘制材料的相图来优化。柱子的各向同性取向将通过改变衬底的表面能和表面形貌以及施加电场和磁场来实现。离子传输、通道的局部和宏观排列以及聚合物基质的动力学都代表了这些材料的关键特征。离子扩散、沟道排列和沟道缺陷结构的多模式核磁共振测量将为理解和设计这些新材料提供宝贵的信息。吸附离子和D2O以及附着在超分子结构上的特定2H标记的2H核磁共振谱将报告材料的取向分布，并将得到透射式和掠入射X射线散射的补充。多轴核磁共振扩散测量和电泳迁移率测量将提供关于膜性质对离子传输影响的补充信息。离子导电性实验将通过阻抗谱和液池中的膜电位测量来进行。选择性结构变化，包括引入光致变色基团，将研究结构/电导关系，并获得具有光控离子电导的膜。

We will develop ion-selective membranes by directed self-assembly where the ion channels are formed by supramolecular complexes. Previously, we have shown that wedge-shaped amphiphilic π-stacked molecules with focal hydrophilic sulfonic acid head groups can self-assemble into supramolecular columns, in which the sulfonic groups are stacked to form well defined ion channels. The width and thus the flux through these ion channels can be controlled by the molecular structure of the assembling molecules. The columnar channels will be covalently stabilized by cross-linking and interconnection to a polymer matrix after orientation normal to the surface of the resulting membranes. The membranes will be prepared by photo- or thermo-polymerization of oriented films. The chemical structure of the wedge-shaped molecules will be optimized by mapping the phase diagrams of the material via temperature-dependent X-ray scattering. Homeotropic orientation of the columns will be accomplished by varying the surface energy and topography of the substrate, and by applying electric and magnetic fields. Ion transport, local and macroscopic alignment of channels, and dynamics of the polymer matrix all represent key features of these materials. Multi-modal NMR measurements of ion diffusion, channel alignment, and channel defect structures will provide invaluable information for understanding and designing these novel materials. 2H NMR spectroscopy on absorbed ions and D2O, and on specific 2H labels attached to the supramolecular structures will report on material orientational distributions and will be complemented by transmission and grazing incidence X-ray scattering. Multi-axis NMR diffusometry and electrophoretic mobility measurements will give complementary information on the influence of membrane properties on ion transport. Ion conductivity experiments will be performed by impedance spectroscopy and by means of membrane potential measurements in a liquid cell. Selective structural variation including introduction of photochromic groups will be studied regarding the structure / conductivity relationships, and to obtain membranes with photocontrollable ion conductivity.