Enhancement of the superoleophobic properties of fluorinated PEDOP using polar glycol spacers
Résumé
The formation of superoleophobic materials is extremely important for various potential applications but are extremely difficult to obtain due to the low surface tension of oils. Here, we synthesized original fluorinated (C4F9, C6F13 and C8F17) 3,4-ethylenedioxypyrrole (EDOP) derivatives with polar glycol spacers (diethylene glycol or triethylene glycol) in order to enhance the superoleophobic properties by electropolymerization. The mobility of the glycol spacers induces steric hindrance during electropolymerization and affects the presence of surface nanoporosity. However, the superoleophobic properties of fluorinated PEDOP can be improved, even if the presence of nanoporosity decreases, on condition that a high degree of nanostructures is preserved around the surface microstructures. This is possible by controlling the length of the fluorinated chain and the length of the glycol spacer. Using a diethylene glycol spacer and a C8F17 chain it is possible to obtain superoleophobic properties with diiodomethane contact angle = 153.0°, sunflower oil contact angle= 148.3° and hexadecane contact angle = 148.0°, and with also low oil adhesion. The micro and nanostructures present on the surface and the high intrinsic oleophobic properties of the polymer allow to stabilize the Cassie-Baxter state.