Hydrophobic coating deposition

Figure 4. Thickness of hydrophobic coatings deposited with scanning atmospheric CH/He plasma (if power = 250 W). The insets show the AFM image (1.5/jmxl.5pm) and line profiles of the 11-pass deposited...

Hydrophobic coatings composed of silicon- and fluorine-containing polymeric materials as well as polyurethanes have been studied because of the relatively good clinical performances of Silastic , Teflon , and polyurethane polymers in cardiovascular implants and devices. Polymeric fluorocarbon coatings deposited from a tetrafluoroethylene gas discharge have been found to greatly enhance resistance to both acute thrombotic occlusion and embolization in small diameter Dacron grafts. 

An AFM study of the topology of polymer spin-coated depositions of Glu-containing ELPs, from acid and basic solutions, on a Si hydrophobic substrate at temperatures below Tt has shown that in acidic conditions, the polymer deposition just shows a flat surface without particular topological features (Fig. 10a). 

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. 

The activation and dissociation of CH4 near the substrate surface lead to deposition of hydrophobic coatings on the surface. The hydrophobic coating layer thickness can be easily controlled with the number of passes under the scanning atmospheric CH4/He plasma. The deposition rate is 14 nm for the first pass and then slightly decreases in subsequent passes. (Figure 4). The deposited film surface is very smooth. The coating thickness is very uniform over the entire treated area. 

Figure 7. Realization of ultra-hydrophobic optical surfaces by coating deposition on glass substrates (schematically).

Figure 16. AFM topography image (1x1 pm ) of an ultra-hydrophobic AI2O3 single layer coating, deposited by magnetron sputtering.

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