Development of Chemically-Tailored Copolymer Nanofiltration Membranes

In this dissertation, the development of polymeric nanofiltration membranes that can be chemically tailored for potential applications are introduced. In general, membranes derived from copolymer materials demonstrate an advanced separation platform due to their straightforward fabrication and highly ordered, yet tunable nanostructures. The well-defined pore structure derived from self-assembled morphology exhibit advances in both selectivity and permeability. To date, the most common applications of copolymer membranes are limited to particle filtration by size exclusions. In this research, further efforts are made to selectively incorporate chemical functionalities into this system while taking advantages of its unique structure that combines self-assembly and an amphiphilic grafted morphology. When the copolymer material is fabricated into a membrane, the reactive groups uniformly distribute within the nanochannel generated by phase separation of side chains and backbones. The reactive groups introduced to pore walls allow for the facile solid-state functionalization of the membrane and consequently enhance the membrane performance in multiple applications. Performance tests of the membrane suggest significantly enhanced charge-selectivity while the overall membrane nanostructure remains unchanged after chemical modification. Furthermore, functionalization using a novel micro-patterning technique allows the development of a fast and versatile modification of membrane chemistry, which results in more selective and chemically affiliated separations. By engineering structural and chemical properties, the functionalized membrane shows its excellence in performance of facilitated ion transport and fouling resistance. The versatile and precise control over membrane chemistry at the microscale provided by the technique suggests the potential in future development of a variety of highly selective membranes.