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Directional Fluid Gating by Janus Membranes with Heterogeneous Wetting Properties for Selective Oil–Water Separation
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posted on 2017-05-19, 00:00 authored by Prashant Gupta, Balasubramanian KandasubramanianThe rising oil seepage
accidents evolved into a global issue necessitating immediate counter
measure to abridge its catastrophic repercussions on sensitive marine
ecosystem urging innovative techniques for effective oil/water separation.
Here, we report surface tailored wettability modified superhydrophobic/superoleophilic
Janus membrane by impregnating nonionic surfactant stabilized nanosized
polytetrafluoroethylene (PTFE) dispersion polymerized via nonfluorinated
processing aid onto cotton substrate using the Meyer rod-coating technique,
exhibiting excellent separation efficiency up to 98% with various
petroleum products and retaining its intrinsic properties for at least
30 recurrences. Morphological analysis revealed the generation of
closely spaced irregularly patterned nanospindles on the microfibral
cotton surface devising hierarchical dual-scale surface architecture,
followed by superhydrophobicization (WCA 168° ± 3°)
and low ice-adhesion, illustrating deviation from conventional Wenzel
and Cassie–Baxter wetting theories. The developed membrane
exhibited flame retardancy, anti-icing characteristic, and retained
its superhydrophobic/superoleophilic characteristic of Janus membrane
in hyper-saline solution, UV-irradiation of wavelenghth 254 nm, high
temperature of 150 °C, and subzero temperature of −20
°C. Furthermore, we hypothesized the developed membranes as a
directional fluid diode, allowing lower surface tension liquids (oil)
to permeate while barring higher surface tension liquids (water) from
penetrating, and the breakthrough pressure of 0.65 kPa for water permeation
was also mathematically calculated. This study systematically exemplifies
the reported fabric as a potentially competent alternative for cleaning
massive marine oil seepages.
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breakthrough pressureJanus Membranescounter measurehyper-saline solutionsuperhydrophobicoil seepage accidentsDirectional Fluid Gatingdispersion polymerizedmicrofibral cotton surfacemarine ecosystem30 recurrencescotton substrateseparation efficiencyflame retardancymarine oil seepageswater permeationpetroleum productsfluid diodeHeterogeneous Wetting Propertieswavelenghth 254 nmnanosized polytetrafluoroethylene0.65 kPanonfluorinated processing aidreport surfacesurface tension liquidsJanus membraneWCAMorphological analysisdual-scale surface architectureMeyer rod-coating techniquePTFE
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