title: Tailor-made polyamide membranes for water desalination.
abstract: Independent control of the extrinsic and intrinsic properties of the polyamide (PA) selective layer is essential for designing thin-film composite (TFC) membranes with performance characteristics required for water purification applications besides seawater desalination. Current commercial TFC membranes fabricated via the well-established interfacial polymerization (IP) approach yield materials that are far from ideal because their layer thickness, surface roughness, polymer chemistry, and network structure cannot be separately tailored. In this work, tailor-made PA-based desalination membranes based on molecular layer-by-layer (mLbL) assembly are presented. The mLbL technique enables the construction of an ultrathin and highly cross-linked PA selective layer in a precisely and independently controlled manner. The mLbL-assembled TFC membranes exhibit significant enhancements in performance compared to their IP-assembled counterparts. A maximum sodium chloride rejection of 98.2% is achieved along with over 2.5 times higher water flux than the IP-assembled counterpart. More importantly, this work demonstrates the broad applicability of mLbL in fabricating a variety of PA-based TFC membranes with nanoscale control of the selective layer thickness and roughness independent of the specific polyamide chemistry.
authors.affiliation: Department of Chemical and Biological Engineering, Korea University , 5-1 Anam-dong, Seongbuk-gu, Seoul 136-713, Republic of Korea.
authors.forename: Wansuk
authors.initials: W
authors.lastname: Choi
authors.forename: Joung-Eun
authors.initials: JE
authors.lastname: Gu
authors.forename: Sang-Hee
authors.initials: SH
authors.lastname: Park
authors.forename: Seyong
authors.initials: S
authors.lastname: Kim
authors.forename: Joona
authors.initials: J
authors.lastname: Bang
authors.forename: Kyung-Youl
authors.initials: KY
authors.lastname: Baek
authors.forename: Byoungnam
authors.initials: B
authors.lastname: Park
authors.forename: Jong Suk
authors.initials: JS
authors.lastname: Lee
authors.forename: Edwin P
authors.initials: EP
authors.lastname: Chan
authors.forename: Jung-Hyun
authors.initials: JH
authors.lastname: Lee
keywords: molecular layer-by-layer; polyamide; reverse osmosis; thin film composite membrane; water desalination