Silica particles can become hydrophobic through plasma polymerization. In this process, plasma polymerized 1,7-octadiene (ppOD) (related to the diene hydrocarbons) is used to deposit polymer films onto the silica particles. The ppOD films are deposited through the use of radio frequencies, along with a reactor containing a rotating chamber. Using low specific energy plasma conditions, the ppOD films chemically render the silica particles hydrophobic.[6]