Membrane technology has become increasingly important for its high efficiency and low cost, and found extensive applications in diverse fields. However, there is a constant demand for effective methods to improve membrane performances. Ideally, these methods should be nonspecific to the chemical nature of membrane materials and applicable to all membranes currently used. In this talk, we demonstrate that atomic layer deposition (ALD) technique is such a promising method in upgrading membrane performances by precisely tailoring the microstructure and surface properties of membranes with a high controllability. Atomic layer deposition (ALD) is a self-limiting gas-phase deposition method for growing atomic scale thin films of oxides, metals, polymers and many other materials. In a typical ALD process, two precursors are pulsed alternatively and strictly separated from each other in the gas phase by a purge step. This procedure leads to the formation of one monolayer each cycle and the thickness of the deposited layer can be precisely tuned by repeating this procedure. We use different types of membranes including track-etched membranes, polytetrafluoroethylene membranes, as model systems to display the superiorities of the ALD method. The membranes subjected to ALD of metal oxides show synergetically improved performances including continuous adjustable pore sizes, increased water flux, enhanced hydrophilicity and fouling resistance, and improved mechanical and chemical stability. Interestingly, by establishing a transition layer of oxides on membranes via ALD, we are able to build epitaxial nanostructures in the membranes, for example, ZnO nanorods and MOF microcrystals, thus rendering additional functionalities to the membranes.

Advanced membranes enabled by atomic layer deposition

253rd National Meeting (2017)

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