Effect of crosslinker on the wettability and mechanical properties of hydrophobic coatings deposited via atmospheric pressure plasma

Hydrophobic coatings based on dodecyl acrylate (DOCA) and perfluorodecyl acrylate (PFDA) have been generated via "postdischarge" atmospheric pressure plasma deposition. These coatings exhibit a water contact angle (WCA) of around 125 degrees but are accompanied by poor mechanical strength. To improve this property, two different types of chemical crosslinkers, that is, hexanediol methacrylate (HDMA) and hexanediol diacrylate (HDA), are incorporated into the precursor mixture. After plasma polymerization, both coatings with crosslinkers admixture show different wettability behavior. The addition of HDMA reduces the WCA while increasing the mechanical strength, while the addition of HDA retains the initial WCA magnitude while also increasing the mechanical strength. These changes are related to variations of the surface free energy (SFE) and topography of the plasma coatings.