Development of functional surfaces with controllable wettability and water adhesion by utilizing appropriate chemistry and hierarchical roughness

The design of multifunctional surfaces based on biomimetic structures has gained the interest of the scientific community. Such biomimetic structures can be achieved by using suitable coatings onto appropriately micro/nano-structured substrates. Hierarchically roughened surfaces can be prepared by irradiating a metallic or semiconductor surface using ultrafast (femtosecond) laser or by utilizing polymer nanocomposite coatings attached onto the surfaces; suitable chemistry of the coatings provides the desired functionality. We use polymer nanocomposite coatings onto polymeric substrates, where the inorganic particulate additives create the appropriate roughness and the polymer matrix provides the proper functionality, which can produce superhydrophobic and water repellent surfaces as well as superoleophobic ones. Second, we will show that allowing a laser irradiated metallic surface to remain under low temperature heating or under moderate vacuum can lead to the development of superhydrophobic and, even, water repellent metal alloy surfaces; the ones that remained under vacuum were water-repellent whereas the ones that underwent thermal processing exhibited superhydrophobicity with high water adhesion.