Natsuki, YES to 1 contact angles much greater than 70 simple chemical work gives up to 130. Yes to 2 at room temperature dependent upon chemistry I have 5 year old microscope slides that have a contact angle of 103. The same as when we produced them 5 years ago, they have been sitting on my desk for the last 5 years. Do not know about the thermally stable at 800-900 C we have never been tested that high. This could be the reason some of our customers are asking for high temperature chemical delivery systems. Chemically stable within reason in alkaline solutions what PH?. Bill Moffat -----Original Message----- From: mems-talk-bounces@memsnet.org [mailto:mems-talk-bounces@memsnet.org] On Behalf Of Miyakawa, Natsuki Sent: Tuesday, November 17, 2009 2:06 AM To: General MEMS discussion Subject: [mems-talk] Turning Si surface hydrophobic Dear all, Does anyone of you know some methods to turn the surface of thermally oxidized Si hydrophobic (say contact angle > 70°)? The hydrophobisity should be long-term stable (> years @ room temperature), thermally stable (> 1h @ 800-900°C), and chemically stable (esp. under alkaline conditions). Thank you! Natsuki