Authors: A. Milionis, D. Fragouli, G.C. Anyfantis, I. Bayer, R. Cingolani, A. Athanassiou
Affilation: Italian Institute of Technology, Italy
Pages: 592 - 595
Keywords: superhydrophobicity, magnetic nanoparticles, magnetic actuation, nanoroughness
Hybrid organic/inorganic surfaces are engineered by exploiting photo-lithographically tailored patterns of SU-8 polymer nanocomposites containing 2% wt colloidal nanoparticles of iron oxide. The role of the magnetic nanoparticles has two aspects. The first one is that upon the application of an external magnetic field perpendicular to the surface, vertical alignment of the nanoparticles is obtained, increasing the roughness of the surface, and the second one is that after the UV photopatterning the resulting pillars are able to move upon the application of an external magnetic field. Consequently, the resulting nanocomposite pattern has the advantage both of the micro-roughness created by the SU-8 pillars and the nano-roughness obtained by the magnetic nanostructures protruding from the surface due to the magnetic allignment prior to the UV curing. These results to a more hydrophobic surface compared to the same pillars formed only with the SU8. The actuation of these structures by the external magnetic field is able to drive the movement of water drops deposited on them towards specific directions. For the further modification of these smart surfaces it is applied on the final surface a coating of superhydrophobic polytetrafluoroethylene particles with the spraying technique, enhancing further the hydrophobicity of the nanomposite system.