Membrane-based chemical separations are essential to the production of food, the purification of drinking water, and the development of therapeutic medicine. However, advanced technologies must be employed to lower the costs of many current membrane purification procedures. For example, reverse osmosis separation technology used for seawater desalination was once prohibitively expensive in terms of cost and energy consumption. However in recent decades, optimization of the reverse osmosis membrane material and structure made it a competitive technology for water treatment. Similar opportunities exist for advanced membrane separations to replace other well-established processes that are energy inefficient and environmentally-taxing such as chromatography and extraction. However, doing so will require transitioning to designer, self-assembled nanomaterials in order to produce next-generation membranes with well-defined and tunable nanostructures. This award will study the fabrication of block copolymer-based membranes and evaluate their structure and performance.
The objective of this research project is to identify the key material relationships that control the interplay between processing, nanostructure, and performance of block-polymer-based membranes created using self-assembly and non-solvent induced phase separation coating process. Membranes will be prepared at the laboratory-scale initially using custom synthesized triblock molecules. Separation performance will be correlated with the nanostructure of the membrane and physicochemical properties of the self-assembled triblock polymer molecule. Evaporation-controlled rheological measurements will be performed to quantify the mechanical properties and assembly kinetics during the early-stage formation of the active layer. This will allow for the determination of the optimum casting solution concentration, solvent evaporation rate, and evaporation period required to fully translate the lab-scale coating process to scalable manufacturing of high-performance membranes using a roll-to-roll coater. The primary outcome of this research project will be the large-scale fabrication and demonstration of a high-performance membrane with tunable separation performance and selectivity that can be processed with modern high-throughput manufacturing technology. The fundamental processing-structure-property relationships identified here will lead to advances in membrane design and fabrication in addition to providing new avenues of exploration within macromolecular processing science.
