(552g) A Hydrophilic/Oleophobic Perfluoropolyether Coating for More Efficient Microchannel-Based Oil-Water Separation

A nanometer-thick hydrophilic/oleophobic perfluoropolyether coating (Zdol) is fabricated on glass slides via a simple dip coating process, which has a low water contact angle (<20°) and high hexadecane contact angle (>65°). The longevity of such coating has been tested after soaking the coated glass slides in real samples of produced water and mixtures of several organic solvents. As indicated by the results of contact angle and ellipsometry, there is still a nanometer-thick layer of Zdol that remains attached to the glass substrate after the immersion tests without considerable drop on its oleophobicity. The FTIR spectrums also confirmed the existence of the peak corresponding to C-F group of Zdol. Such coatings have been applied in a 2D oil-water separation device and achieved a separation efficiency above 95%. Even with the coating immersed in various liquids after up to 100 hours, the separation efficiency, instead of decreasing significantly, still stays at ~90%. This work has shown a great potential of such coating in liquid-liquid separation & extraction.