Claudio Mortier

Sticky superhydrophobic hard nanofibers from soft matter

Here, we show the possibility to change superhydrophobic properties from soft to hard polymer nanofibers by the control of molecular structure and branching. In fact, we report the synthesis of original monomers derived from 3,4-propylenedioxythiophene (ProDOT) and bearing two branched alkyl chains and their electrodeposition by cyclic voltammetry. We point out that the hydrocarbon moiety (cheaper, readily available, non-toxic) can be an alternative to long fluorocarbon chains (expensive, requiring extensive synthesis, bioaccumulable) to achieve anti-wetting properties. Moreover, we show that the change in the size of branched chains can affect the surface morphology, from soft to hard nanofibers with a high increase in water adhesion due to a lower intrinsic hydrophobicity (sticky superhydrophobicity or parahydrophobicity). We demonstrate the possibility to produce them from soft matter, i.e. polymers. In the case of the hard nanofibers, cross-section images reveal that these fibers are vertically aligned to the substrate. Moreover, we show that the height and the diameter of the hard nanofibers, as well as the distance between the fibers can be controlled by the number of deposition scans. Such materials could be used for biomedical applications, for example.

A bioinspired approach to produce parahydrophobic properties using PEDOP conducting polymers with branched alkyl chains

Abstract In nature, several plants and insects, such as the Rosa montana petals or the gecko foot, are highly hydrophobic but with an extremely high water adhesion. These properties are called parahydrophobic. Here, in order to reproduce such properties we have developed original 3,4-ethylenedioxypyrrole monomers containing branched alkyl chains in order to have intrinsically hydrophilic polymers. In certain conditions, the electrodeposited conducting polymer films are parahydrophobic due to the presence fibrous structures forming large agglomerates. On such surfaces, a water droplet deposited on them remains stuck even after a substrate inclination of 180°. Such properties are extremely interesting for applications in water harvesting, for example.

Superhydrophobic and superoleophobic poly(3,4-ethylenedioxypyrrole) polymers synthesized using the Staudinger-Vilarrasa reaction

Abstract Vegetal and animal reigns offer many examples of surfaces with surprising and interesting wetting properties. As example, springtails present superoleophobic properties allowing to live in soil and Lotus leaves show self-cleaning ability even under rainfalls. Indeed, it is known that self-cleaning properties can help to remove dust and particles during rainfalls and as a consequence to clean the surface. The bioinspiration of these surface properties is of a real interest for industrial applications in the nanotechnology field such as photovoltaic systems or anti corrosive material. Here, we use a strategy based on electropolymerization to obtain these properties. The Staudinger-Vilarrasa reaction is used to prepare innovative 3,4-ethylenedioxypyrrole (EDOP) monomers with fluorinated chains. Using C6F13 or C8F17 chains, the polymer surfaces formed after electrodeposition show superhydrophobic and superoleophobic features. Here we study the surface wettability depending on the surface energy (based on the perfluorinated chain length), the surface roughness and morphology.