Control of the water adhesion on hydrophobic micropillars by spray coating technique

• Published in: Colloid and polymer science Vol. 291; no. 2; pp. 401 - 407
• Main Authors: Milionis, Athanasios, Martiradonna, Luigi, Anyfantis, George C., Davide Cozzoli, P., Bayer, Ilker S., Fragouli, Despina, Athanassiou, Athanassia
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer-Verlag 01.02.2013; Springer Nature B.V
• Subjects: Adhesion; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Complex Fluids and Microfluidics; Contact angle; Contact Angle Hysteresis; Devices; Food Science; Nanocomposites; Nanomaterials; Nanostructure; Nanotechnology and Microengineering; Physical Chemistry; Polymer Sciences; Roughness; Short Communication; Soft and Granular Matter; Spray coating; Poly(tetrafluoroethylene) (PTFE); Nanoroughness; Micropatterning; Iron oxide; SU-8; Superhydrophobicity; Hysteresis
• ISSN: 0303-402X; 1435-1536
• DOI: 10.1007/s00396-012-2752-5

We present an alternative approach for controlling the water adhesion on solid superhydrophobic surfaces by varying their coverage with a spray coating technique. In particular, micro-, submicro-, and nanorough surfaces were developed starting from photolithographically tailored SU-8 micropillars that were used as substrates for spraying first poly(tetrafluoroethylene) submicrometer particles and subsequently iron oxide nanoparticles. The sprayed particles serve to induce surface submicrometer and nanoscale roughness, rendering the SU-8 patterns superhydrophobic (apparent contact angle values of more than 150°), and also to tune the water adhesion between extreme states, turning the surfaces from “non-sticky” to “sticky” while preserving their superhydrophobicity. The influence of the chemical properties and of the geometrical characteristics of the functionalized surfaces on the wetting properties is discussed within the frame of the theory. This simple method can find various applications in the fabrication of microfluidic devices, smart surfaces, and biotechnological and antifouling materials.