Surface structuration (micro and/or nano) governed by the fluorinated tail lengths toward superoleophobic surfaces

Hervé Bellanger (1) , Thierry Darmanin (1) , Frédéric Guittard (1)

1 Surfaces & Interfaces

The obtaining of Surfaces with Superoleophobic properties is a very recent field of investigation. Oils have a low surface tension and thus a high ability to wet any surfaces. Surfaces with such properties are consequently very difficult to produce. To reach superoleophobicity, it is necessary to combine an intrinsically oleophobic material with a peculiar surface morphology, as double scale roughness (micro and nano). The elaboration of superoleophobic surfaces usually involves multi-step processes to create the surface morphology and post-treatment with fluoropolymers. Our group is able to produce superhydrophobic and superoleophobic surfaces using a controllable, easy to implement, fast and one step method to produce such surfaces : the electrochemical deposition of conducting polymers.1,2 Indeed, a film can be created at the surface of a metallic substrate immersed in a solution containing a fluorinated monomer by applying a potential step. During the nucleation and growth process, a peculiar morphology (usually micro and/or nano roughness), governed by the parameters of the experiment, is created and can lead to superoleophobic surfaces. We have synthesized original monomers, presented in figure 1, by coupling fluorinated tails F-octyl, F-hexyl, F-butyl to N-substituted 3,4-ethylenedioxypyrrole. The electrodeposited polymer films were characterized by static and dynamic contact angle measurement with various probe liquids, optical profilometry and scanning electron microscopy. In the aim to reach superoleophobic properties, a common approach is to increase the number of fluoromethylene units of the surface post-treatment agent. Here, surprisingly, it is possible, in one step, to reach more efficient anti-oil surface properties by decreasing the length of the fluorinated tail (F-octyl to F-hexyl). This fact can be explained by a double scale of structuration (micro and nano) induced using only F-hexyl tails.

Domaines: Matériaux

Hervé Bellanger, Thierry Darmanin, Frédéric Guittard. Surface structuration (micro and/or nano) governed by the fluorinated tail lengths toward superoleophobic surfaces. International Symposium on Fluorine Chemistry, Feb 2012, New Delhi, India. ⟨hal-00847205⟩