Superhydrophobic coatings

Direct fabrication of superhydrophobic coatings on metal surfaces has indeed brought new research trends to the corrosion problem. Two main approaches have been developed... 

Zhai L, Cebeci Ff, Cohen RE, Rubner MF. 2004. Stable superhydrophobic coatings from polyelectrolyte multilayers. Nano Lett 4(7) 1349 1353. 

Mixed bmshes of hydrophobic and hydrophilic polymers grafted onto Au-NPs were also used as stabilizers for styrene droplets. Subsequent suspension polymerization of styrene led to PS particles with Au-NPs on their surface. Such raspberry particles might open new perspectives for superhydrophobic coatings with dual-size roughness. " ... 

For deposition of hydrophobic coatings, a mixture of CHVHe gases was used in the plasma. Superhydrophobic coatings were created with a Cp4/H2/He plasma. The deposited coatings were analyzed with PM-RAIRS, x-ray photoelectron spectroscopy, scanning electron microscopy (SEM, JEOL 6700 F - FESEM), atomicforce microscopy (AFM, Molecular Imaging SPM microscope with RHK controllers), ellipsometiy, and water contact angle measurements. 

Figure 8. PM-RAIRS andXPS (inset) of superhydrophobic coatings deposited with scanning CF4/H2/He plasma (rf power = 300 W). The number of plasma treatments is indicated in the figure. (9)...

Figure 5. Optical images of water droplets ( 2 mm diameter) on a superhydrophobic coating deposited on (a) gold film, (b) Si wafer, (c) Kimwipe tissue and (d) cotton (reprinted with permission from American Chemical Society [36]).

Figure 8. A half-splash of a Janus sphere, where only half the sphere is coated with a superhydrophobic coating.

In the present study, we have successfully developed a sol-gel method to fabricate translucent superhydrophobic coatings on a glass surface. Compared to the reported methods, the sol-gel method in this study uses relatively cheaper raw materials and the process is also much simpler and operable with fewer steps and does not require high temperature treatment, which makes this method more economical and feasible. 

Stearic acid was used as a water-repellent agent for surface modification [25]. The as-prepared coatings were dipped into 10 mmol/1 stearic acid/hexane solution for 24 h and then washed thoroughly with hexane. After drying in an oven at 60°C, the superhydrophobic coatings obtained were translucent. 

In the present work, translucent superhydrophobic coatings have been successfully prepared by a sol-gel method based on alumina nanoparticles. The coatings pos-... 

Figure 1. Schematic for producing a superhydrophobic coating on device surfaces using oxygen plasma treatment, (a) The surface of the device is coated with a layer of fluoropolymer (Teflon), (b) Oxygen plasma treatment is used to roughen the surface of fluoropolymer. (c) A superhydrophobic surface is obtained after the oxygen plasma treatment.

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