Small Grant for Exploratory Research: Molecular Engineering at Ultrathin Organic Films for Membrane Separations

膜在分离过程中的有效性是 基于其选择性和渗透性的程度，或 吞吐量 不幸的是，选择性和渗透性 通常是权衡-同样的机制，控制 选择性，如孔径大小，调节材料的流量 通过膜。 这个SGER提案建议制造 复合膜，以最大化选择性和 磁导率 使用多孔基底作为背衬 材料，从而提供机械强度并确保高 磁导率 然后通过安装一个 在背衬上的无孔微结构化薄膜 床单。 PI建议将这些微结构薄膜制成 内聚的、分子有序的、有机单层或多层的 膜形成的朗缪尔Blodgett技术或自 通过从溶液中吸附组装。 的渗透性 这些膜对感兴趣的气体的敏感性将通过使用 石英晶体微量天平或表面声学天平 波装置 在这种类型的测量中， 附接到（通常）石英压电晶体，以及 将振荡电场施加到晶体上。 这 应用程序使声波以预定的速度传播， 特定的共振频率。 质量的微小变化 膜可以通过共振频率的偏移来检测， 水晶 胶片将暴露在一种气体中， 环境，频率偏移将在时间上测量， 以测量渗透率。 该项研究将集中 微结构和物理化学 膜的性质与渗透性有关。 特别是不同流动性、表面 特征、化学性质和缺陷结构将被 检查。

The effectiveness of a membrane in a separation process is based on the degree of its selectivity and its permeability or throughput. Unfortunately, selectivity and permeability are generally traded off - the same mechanisms which control selectivity, such as pore size, regulate the flux of material through the membrane. This SGER proposal suggests fabricating composite membranes in order to maximize both selectivity and permeability. A porous substrate is used as the backing material thus providing mechanical strength and insuring high permeability. Selectivity is then controlled by mounting a nonporous ultrathin microstructured film over the backing sheet. The PI suggests making these microstructured films out of cohesive, molecularly ordered, organic mono- or multi-layered films formed either by the Langmuir Blodgett technique or self assembly via adsorption from solution. The permeability of these films to gases of interest will be measured by using either a quartz crystal microbalance or a surface acoustic wave device. In this type of measurement this film is attached to a (typically) quartz piezoelectric crystal, and an oscillating electric field is applied to the crystal. This application causes an acoustic wave to propagate with a particular resonant frequency. Minute changes in mass of the film can be detected by shifts in the resonant frequency of the crystal. The film will be exposed to a gaseous environment, and frequency shifts will be measured in time in order to measure the permeability. The study will focus on how the microstructure architecture and physicochemical properties of the films relate to the permeability. Specifically films of different fluidity, surface characteristic, chemistries and defect structure will be examines.