Monitoring diffusion processes in nanoporous block copolymer membranes with high spatial and temporal resolution

该项目旨在研究具有高时间和空间分辨率的具有纳米孔径的可切换两嵌段共聚物膜的传输过程。膜将通过非溶剂诱导相分离(NIPS)从合适的两亲性嵌段共聚物中制备，该嵌段共聚物将使用活性/可控聚合技术来合成。疏水的(聚苯乙烯)嵌段将形成结构的基质，而亲水的链段覆盖孔壁。作为亲水性嵌段，我们计划使用一种材料，它在水介质中的溶解度可以通过外部刺激可逆地改变。可能的触发因素是pH(例如，聚(2-二甲氨基甲基丙烯酸乙酯，PDMAEMA))、温度(来自PDMAEMA和聚甲基丙烯酸甲酯(PMMA)的共聚物)，或特定波长的光照射(聚(N-异丙基甲基丙烯酰胺)、PNiPAAm和聚(螺吡喃甲基丙烯酸酯，PSPMA)的共聚物)。将使用带有适当尺寸(d&lt；50 nm)的荧光标记颗粒的3D单粒子光学跟踪(3D-SPOT)来监测传输过程。记录的扩散路径将与使用半薄切片(200-300 nm)的透射电子显微镜断层扫描(TEMT)重建的膜的3D模型进行比较。在此之前，膜将被嵌入合适的树脂中。

The proposed project aims at the investigation of transport processes in switchable diblock copolymer membranes with nanometer-sized pores with high temporal and spatial resolution. The membranes will be prepared by non-solvent induced phase separation (NIPS) from suitable amphiphilic block copolymers which will be synthesized using living/controlled polymerization techniques. The hydrophobic (polystyrene) block will form the matrix of the structures and the hydrophilic segments covers the pore walls. As hydrophilic block we plan to use a material, which solubility in aqueous media can be reversibly altered through external stimuli. Possible envisioned triggers are changes in the pH (e.g., poly(2-dimethylaminoethyl methacrylate), PDMAEMA), temperature (copolymers from PDMAEMA and poly(methyl methacrylate), PMMA), or the irradiation with light of a specific wavelength (copolymers of poly(N-isopropylmethacrylamide), PNiPAAm, and poly(spiropyrane methacrylate), PSPMA). The transport processes will be monitored using 3D single particle optical tracking (3D-SPOT) with fluorescently labeled particles of suitable size (d < 50 nm). The recorded diffusion paths will be compared with reconstructed 3D models of membranes by transmission electron microscopy tomography (TEMT) using semi-thin microtome slices (200-300 nm). Prior to that, the membranes will be embedded within suitable resins.