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Transport Phenomena at the Nanoscale

Final Report Summary - TPN (Transport Phenomena at the Nanoscale)

The objectives of the IRG grant included studying if and how nanometre scale confinement affected the flow of liquids inside nanochannels. From our preliminary study in this area, a review on liquid imbibition in nanochannels was published. Thanks to the IRG funds we have been able to perform water flow measurements in nanoporous alumina membranes (Figure 1). We have shown, for the first time, that liquid flow enhancement can be achieved also in hydrophilic nanochannels (Figure 2(left)).

Following on these results I have been awarded a grant from the Royal Society to establish a collaboration with a mathematician in Italy to develop a theoretical model to explain this unexpected phenomenon. The model we have developed not only can explain the flow enhancement in alumina nanochannels but was capable of capturing experimental and molecular dynamics results of water flow in carbon nanotubes (Figure 2(right)).

The cumulative outcome of this research has significant potential to change the design of ceramic membranes used for the filtration of liquids. While polymeric membranes currently dominate the market for water filtration in general and desalination in particular, ceramic membranes could one day replace them due to higher mechanical and chemical resistance. Before this can happen, though, their transport properties (permeability and salt rejection) have to be significantly improved. Our results show that it is possible to fabricate nanoporous alumina membranes with narrow pore size distribution in the ultrafiltration range with superior transport properties due to flow enhancement effects. In addition, these membranes are hydrophilic, with very low contact angle, a property that can be used to obtain low fouling membranes. We are now exploring further development of these membranes for potential commercial exploitation.

Results from the IRG-funded work and further development can be found online at the following address: