17982
A superhydrophobic - superoleophilic PVDF membrane is fabricated via an inert solvent - induced phase inversion for effective separation of both micrometer and nanometer - sized surfactant - free and surfactant - stabilized water - in - oil emulsions solely driven by gravity , with high separation efficiency ( oil purity in filtrate after separation > 99 . 95 wt % ) and high flux , which is several times higher than those of commercial filtration membranes and reported materials with similar permeation properties .
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Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
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