Single-step deposition of hexamethyldisiloxane surface gradient coatings with a high amplitude of water contact angles over a polyethylene foil

One interesting category of nano- and micro-engineered surfaces is surface gradients, which allow the controlled optimization of biointerfaces at a small scale in an extended area length. Plasma coatings offer a large diversity of functionalities at the nanoscale, accompanied by high chemical stability and adhesion on a variety of substrates at ambient temperature. Atmospheric-pressure plasma-assisted deposition could be employed for the generation of surface gradients on thermosensitive materials. In this study, a corona plasma jet is used to deposit polydimethylsiloxane/SiO2-like surface gradients on polyethylene foil by varying the O2 concentration in the discharge during the movement of the plasma source. We obtained, in a single-step approach, gradient coatings along a length of ∼10 cm, with a gradual variation of both chemistry and surface energy.