Dialon Coating

The fluorinated DLC is akin to teflon that is essentially fluorine coated diamond atoms that form a single file. In fact, this structure maybe named dialon for diamond-teflon for future reference. Figure 10.9 is a schematic diagram of teflon compound.

The fluorination cannot only lubricate the DLC, but also enhance its adherence to the substrate, particularly on the surface of polymers. Moreover, the fluorine atoms attached to DLC can repel water or other polarized molecules so the surface is highly hydrophobic. The dialon-coated surface has the super lotus effect that can clean itself spotlessly. Figure 10.10 illustrate the electrostatic repulsive effect of hydrogen and fluorine terminated DLC.

Dialon is virtually frictionless (frictional coefficient can be less than 0.001 if rubbing against itself). If Dialon were coated on bearings, it would be the most slippery surface of all materials. Dialon

Figure 10.8. The scratch line on DLC can be dramatically reduced when its surface is fluorine terminated (Source: Redrawn from Miyake et al. (1991).

Figure 10.9. A teflon (poly Tetra Fluoro Ethylene) molecule is made by replacing hydrogen with fluorine on diamond-like thread of ethylene.

Figure 10.10. Hydrogen terminated DLC may repel each other (left), but fluorine terminated DLC can be levitating without contact (right).

Figure 10.10. Hydrogen terminated DLC may repel each other (left), but fluorine terminated DLC can be levitating without contact (right).

may also be applied to biological objects, such as vein stents or heart valves. In this case, dialon can repel blood platelets or body fluid so the artificial implants may last long or even survive the life of its host (Fig. 10.11).

+1 0

Post a comment