PTFE is resistant to van der Waals forces, which makes it the third lowest-friction material (aluminium magnesium boride being first at 0.02 and diamond-like carbon second). This property is a key feature of its usage in a variety of applications such as bicycle wheels and bearing systems, in aerospace and industrial coatings, and as the sole material used for thread seal tape on many types of faucets. PTFE also has a very low coefficient of friction with itself. This is an important attribute of the material when it is coated with a hydrophobic surface, as the PTFE is able to repel water molecules from the surface of the substrate. This allows the PTFE to repel dirt and microbes, and provides a barrier that is chemically compatible with most solutions and autoclavable at high temperatures.

The PTFE surface is hydrophobic because it contains carbon-centered rings rather than oxygen-centered atoms. These ring structures are smaller than the surrounding carbon, which reduces the contact angle. This effect is also present in other fluoropolymers, including tetrafluoroethylene and ethylenetrifluoroethylene, but it is a stronger force with PTFE than those polymers.

In the study, CarboSil-PTFE and SNAP-PTFE polymer composites were soaked in PBS for 24 h at 37 degC with constant shaking. The resulting surface tension was measured with an Ossila contact angle goniometer. The results showed that despite the hydrophobic PTFE coating, neither the PTFE nor CarboSil lost significant water wettability over time. The result is consistent with FTIR analysis, which can be limited in its ability to detect subtle changes of coating loss under robust physiological conditions.