Fig. 3.

Spatular pull-off force of specimen 1 vs. the contact angle θ_W of a water drop on four types of Si wafers and on glass. Wafer families N and T differ by the thickness of the top amorphous Si oxide layer. The “phob” type was obtained from “phil” type wafers by deposition of octadecyl-trichlorosilane. The relative humidity during the experiment was 52%. For comparison, the pull-off forces on a glass substrate (θ_W = 58.4°) measured at comparable humidity (glass square data point taken from Fig. 4) is included. Additionally, pull-off forces while completely submerged under water [open circles labeled with glass(w) and N-phil(w)] are displayed.