Developing
bactericidal membranes is of interest to the membrane
industry in seawater desalination and other water purification processes.
The pivotal step for the fabrication of a high performance bactericidal
membrane is the delicate design of bactericidal materials, which should
feature high efficiency, long lifetime, and low cost. Ultrasmall silver
nanoclusters (AgNCs, less than 2 nm, which could maximize the use
of active Ag species) have recently emerged as a promising class of
inorganic antimicrobial agents. Leveraging on the unique properties
of AgNCs, here, we developed an efficient protocol to integrate AgNCs
into polymeric membranes (e.g., forward osmosis (FO) membranes), leading
to the formation of a high performance antimicrobial thin-film composite
membrane. In particular, the AgNC-modified membranes can effectively
inhibit the growth of Escherichia coli, without obvious activity decay over a test period of 1 month. In
addition, the strong thiolate-metal interaction in thiolate-protected
AgNCs offers a sustainable and controllable dissolution of silver
ions, acting as active antimicrobial species. More interestingly,
the AgNC-decorated membranes show improved FO performance as compared
to the pristine membranes. The delicate design of AgNCs and the fabrication
protocol developed in this study might provide a promising platform
to fabricate antimicrobial membranes for various industrial applications.