In this work, we present the synthesis of original thieno[3,4- b ]thiophene monomers with rigid substituents (e.g., perfluorinated chains, and aromatic groups) and demonstrate the ability to prepare nanotubular and nanoporous structures via templateless, surfactant-free electropolymerization in organic solvents (dichloromethane). For the majority of synthesized monomers, including a significant amount of water in the electropolymerization solvent leads to the formation of nanoporous membranes with tunable size and surface hydrophobicity. If water is not included in the electropolymerization solvent, most of the surfaces prepared are relatively smooth. Tests with different water contents show that the formation of nanoporous membranes pass through the formation of vertically aligned nanotubes and that the increase in water content induces an increase in the number of nanotubes while their diameter and height remain unchanged. An increase in surface hydrophobicity is observed with the formation of nanopores up to ≈300 nm in diameter, but as the nanopores further increase in diameter, the surfaces become more hydrophilic with an observed decrease in the water contact angle. These materials and the ease with which they can be fabricated are extremely interesting for applications in separation membranes, opto-electronic devices, as well as for sensors.
International audienceSuperhydrophobic and oleophobic surfaces are obtained by electrodeposition of original PEDOT derivatives containing two short fluorinated chains. The liquid-repellent properties are due to the combination of high intrinsic hydrophobicity and oleophobicity of polymers due the presence of two fluorinated chains, and the formation of wrinkles and spherical particles induced by the electrodeposition process. The presence of wrinkles and spherical particles and as a consequence the surface hydrophobicity and oleophobicity is correlated to the fluorinated chain length and electrochemical parameters (the deposition charge for the depositions at constant potential and the scan rate and number of scans for the depositions by cyclic voltammetry). Here, the increase in the number of wrinkles and spherical particles induce an increase in the surface roughness increasing especially the surface hydrophobicity while the surface oleophobicity is not always affected. However, it is possible to increase also the surface oleophobicity by a careful choice in the electrochemical parameters. This work also allows the elaboration of super liquid-repellent surfaces with low fluorine content (materials with low bioaccumulative potential)
An easy synthetic procedure in two or three steps from perfluoroalkylethyl iodide derivatives led to six novel fluorinated carboxylates monomeric and gemini surfactants with one or two hydrophobic tails, respectively: RF(C2H4)CH(CO2(-))2,2Na(+) and [RF(C2H4)]2C(CO2(-)),Na(+), where RF = C4F9, C6F13, and C8F17. These anionic surfactants exhibited very low surface tension from 15 to 33 mN/m as well as low critical micelle concentration until 1.3 × 10(-4) mol/L. Furthermore, the surface properties of the gemini compound with two short fluoroalkyl chains (RF = C4F9) were found to be almost equal to those of the monomeric surfactant with one long fluoroalkyl chain (RF = C8F17), which could provide an interesting alternative to the bioaccumulative long-chain perfluorinated surfactant.
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