Membranes with tailored wettability properties for the generation of uniform emulsion droplets with high efficiency

Membrane emulsification is a promising technology for the production of micro–nano particles, which is able to compete with the conventional mechanical emulsification processes. The production of emulsions with narrow droplet size distribution at dispersed phase fluxes (productivity) sufficiently high to make the process suitable for industrial application is still a considerable challenge. The interfacial tension between the dispersed phase and the membrane pore wall is a crucial parameter to maintain droplets shape while enhancing productivity. In the present paper, a membrane thickness with asymmetric properties in terms of wettability between external and internal sides has been tested in the preparation of W/O emulsions. The membrane surface wettability modification was obtained by adsorption of hydrophobic macromolecules on the lumen side of hydrophilic membrane. Lipase was used as a model macromolecule. W/O emulsion droplets with smaller droplets size have been produced with lipase-loaded membrane compared with the unmodified hydrophilic membrane. High dispersed phase flux of 30 L h−1 m−2 was also obtained with a significant increase of process productivity compared to the use of hydrophobic membranes. These results show that membrane–protein interaction can be used to functionalize opportunely the membrane for membrane emulsification application reducing emulsification time and increasing dispersed phase flux without modifying the control on droplets properties in terms of size and size distribution.