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Scalable Manufacturing of Layer-by-Layer Membranes for Water Purification



Christopher M. Stafford


Water is critical to the health and security of our nation. And as our population expands and water scarcity becomes a reality, we as a people need to think creatively on how we safeguard access to clean water. The manufacturing of today’s state-of-the-art membranes for water purification is based on 1970’s technology of interfacial polymerization of the selective layer directly a porous support. In this, polymerization occurs at the interface of two immiscible liquids, where one liquid is wicked into the porous support. Over the next 40 years, this membrane technology has slowly evolved through an Edisonian, trial-and-error approach. This process makes extremely thin (100’s nm) selective membranes, but these membranes are difficult to characterize due to high roughness and large heterogeneity. Thus, our fundamental understanding of how these membranes work is insufficient to allow rational design of next- generation membranes. Recently, we have developed a layer-by-layer approach using vapor-based deposition where each monomer is deposited in the gas phase, where ideally deposition occurs directly on a porous support. This approach has many advantages over the solution-based approach, such as speed, safety, and scalability. But there are still many challenges yet to overcome, from membrane support design to membrane characterization. In this talk, I will describe our efforts to meet these challenges through judicious experimental design and materials selection, and I will share how some of our measurements have challenged our thinking in how these materials selectively pass water while rejecting salt.
The Bridge


desalination, membranes, polymers, polyamide, layer-by-layer


Stafford, C. (2016), Scalable Manufacturing of Layer-by-Layer Membranes for Water Purification, The Bridge (Accessed July 23, 2024)


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Created December 1, 2016, Updated March 22, 2017