1. Durability of hydrophobic coatings for superhydrophobic aluminum oxide Elliot Jennera a, Charlotte Barbierb b, Brian D’Ursoa a, ∗ a Department of Physics & Astronomy, University of Pittsburgh, Pittsburgh, PA 15260, United States b Oak Ridge National Laboratory, Oak Ridge, TN 37831, United States Paper Survey Advisor : Cheng-Hsin Chuang Advisee ﹕ Wen-Yu Lee Institute of Mechanical Engineering Date ﹕ 2013/10/24 Applied Surface Science 282 (2013) 73– 76

2. 2 Fig. 1. SEM image of a spiked PAA surface in cross section at 20◦ inclination, thickness 4um. Note the visible steps made by alternation of 8 anodization and 7 etching steps. Material and methods – Fabrication Anodization parameters:  Anodization: 320 V, 0.051 A/m 2 at 18-20 ̊ C, 0.1175 M Citric acid  Pore widening etching: 2 wt% Tetramethylammonium hydroxide (TMAH) at 18 ̊ C  Hydrophobic fluoropolymer: Solvey Plastics Hyflon AD-60 750nm

3. 3 Material and methods – Experimental method  F0~F5: Baked for 15 min at 150 ̊ C  After baked: F3: Spin coated at 1000rpm with 2wt% Hyflon in 3M Fluorinert(FC-40) F5: Spin coated with PGMEA:HMDS in 4:1 solution at 4000rpm → Followed by F3 Hyflon solution

4. 4 Fig. 3. Rolling angle as a function of time. A reading of 90◦ indicates the drop adhered up to or past vertical tilt. Results and discussion Fig. 2. Profile image showing contact angle of a drop of water on the material before full immersion in water was undertaken. Drop is held in place with a needle suspended above the surface. 161 o ±1

5. 5 Results and discussion AAOSample Edge Fig. 4. SEM images of samples, taken at a 20◦ angle after testing and cracked to show profile.

6. 6 Thanks for your attention!