Hydrophobic coatings from plasma polymerized vinyltrimethylsilane

Thin-films have been deposited onto silicon and metal substrates by plasma polymerization of vinyltrimethylsilane (VTMS), to provide hydrophobic coati ngs for dropwise condensation of steam. The deposition conditions have been sampled by a set of statistically designed experiments, and the films' thi cknesses, water droplet contact angles, elemental compositions (by XPS), an d -CHx, contents have been measured. There is a strong correlation between these film properties and their deposition conditions. The films that conti nue to provide successful long-term dropwise condensation had been deposite d at a low rate onto heated substrates, such that they have high water cont act angle and high -CHx, content. This required a plasma that provided a lo w electron energy input per precursor species collision.