Amine plasma treatment causes a decrease in WCA due to the incorporation of hydrophilic nitrogen and oxygen moieties [43-45] onto the sample surface. Oxygen functionalities can be incorporated via two different processes. First, the vacuum level does not guarantee total absence of oxygen impurities in the plasma chamber [46, 47]. Second, after plasma treatment, samples are exposed to air which can induce a post plasma functionalization by reaction with oxygen and water vapor