Dip-coating for dodecylphosphonic acid derivatization on aluminum surfaces: an easy approach to superhydrophobicity

An easy approach of rapid dip-coating to superhydrophobic aluminum (Al) surfaces is reported. Dodecylphosphonic acid (DDPA) layers were formed on periodic micro-column-patterned Al surfaces by a rapid dip-coating in a 2 mM DDPA solution in trichloroethylene. It was demonstrated that DDPA layers were derived on Al substrates in a couple of seconds and superhydrophobic Al surfaces were achieved with water static contact and sliding angles of 153° and 5°, respectively. Atomic force microscope and X-ray photoelectron spectroscopy (XPS) measurements showed that multilayer and island structural DDPA layers were formed on Al substrates. XPS analyses demonstrated that DDPA headgroups were connected with Al by P–O–Al bonds which contributed to the excellent durability of the superhydrophobic Al surfaces.