The performance of ultrafiltration (UF) membranes used for liquid separations is often degraded by membrane fouling. The foulants can be partially removed by harsh chemical treatment, causing more energy consumption, loss of productivity, and shortened membrane lifetime. Thus, mitigation of membrane fouling remains a grand challenge for most liquid separation applications. While most antifouling strategies focus on modifying the surface chemistry of the UF membrane, this project aims to use micro and nanoscale patterns on UF membranes as a non-chemical approach to mitigate fouling during active filtration. To achieve this goal, the two specific objectives are: (1) to understand the processing ? structure ? performance relationships for creating patterns onto asymmetric porous UF membranes using nanoimprint lithography (NIL), without sacrificing the permselectivity of the membrane; and (2) to understand the mechanism of how these surface patterns affect fouling of the membranes during filtration. The PIs expect to advance current understanding of how surface topography affects fouling during active filtration. NIL will be applied to create patterns on the surface of the asymmetric UF membrane without sacrificing its permselectivity. Membranes with micro or nanopatterned surface have not been previously been fabricated. The NIL approach is applicable to all UF membranes, thus offering a platform for quantitative physico-chemical insights into the interplay between chemistry and topography on colloidal interactions in complex systems. The comparison of fouling between patterned and flat membranes with identical chemistry will shed light on the explicit role of surface topography on membrane fouling. The integration of lithographic patterns with the filtration membranes will allow the PIs to control the thermodynamic and hydrodynamic interactions between the membrane surface and the feed solution during active filtration. Broader impacts. Results of the project may guide a flexible non-chemical approach to produce UF membranes with reduced fouling and improved energy efficiency with benefits for a broad range of separation technologies. Results of the project will advance our current knowledge on how surface topography affects the membrane fouling during active filtration, which in turn will guide the design of surface patterns for targeting specific separation applications. The proposed educational impact will leverage the exceptional infrastructures for innovation in education and outreach at the University of Colorado to provide new, inspirational educational experiences, with a focus on membrane technology, for students at all levels. Other activities will enhance professional development of graduate students, promote diversity in science and engineering disciplines, and enhance K-12 outreach. The ultimate educational outcome of this proposal is to provide the essential membrane-science focused education to students at all levels, and encourage them to pursue careers in scientific disciplines.
