Researchers at the State Key Laboratory of Solid Lubrication of the Lanzhou Institute of Chemical Physics (LICP), CAS, have received two Chinese invention patents for their preparation techniques of super-hydrophobic surface.

The first patent An Electrochemical Preparation Method of Super-hydrophobic Surface covers the preparation of super-hydrophobic surface on aluminum surface or aluminum alloy surface. The super-hydrophobic surface is prepared as follows: first through electrochemical etching and oxalic acid anodizing of aluminum surface or aluminum alloy surface, coarse surface with micro/nano structure is constructed. Then after the modification of the surface by fluoroalkyl silane with low energy surface, surface with excellent superhydrophobicity is obtained. The sliding angle of water droplets on the surface is less than 2°and water droplets can easily slide on the surface, which endows aluminum surface or aluminum alloy surface excellent self-cleaning property.

According to the researchers, since electrochemical etching and oxalic acid anodizing techniques are already quite mature, with the facile technique mass production can be easily achieved. Moreover, the use of highly corrosive substances can be avoided and no pollution will be caused to the environment. The method can not only be applied in the surface of flat metallic engineering materials but in the inner walls of bending pipes as well. It has potential to be applied in the pipeline transportation system for liquid and research on microflow too.

The second patent is titled A Preparation Method of Super-hydrophobic Titanium Surface and Super-hydrophobic Titanium Alloy Surface. The surface is prepared through the following steps.

First, titanium or titanium alloy go through hydrothermal reaction in alkali liquor after being mechanically polished. Through this micro-nano complex structure is formed on the surface. Then researchers spin coat the surface by chemical modifiers with low surface energy. After all these, titanium surface with both super-hydrophobic, super acidophobic and super alkaliphobic properties is obtained.

The as prepared titanium surface can be applied to reduce resistance and prevent erosion in piping materials for the transportation of liquid, in planes, ships and underwater submarines. It can also be used for antifouling and antirust in household utensils made of titanium or titanium alloy and surface of industrial titanium products. 

The patents are No. ZL200810150857.6 and No. ZL200810183386.9, received on January 26 and February 2 of this year respectively