Hi Bill,

How do you deposit the heptadecafluoride? I am looking for a surface that
remains hydrophobic after patterning. For example: deposit SiO2,
functionalise SiO2 to remain hydrophobic, pattern and etch SiO2 +
hydrophobic layer and  remove mask. The surface must remain hydrophobic
after processing.

Thanks,

Andrew



2009/8/13 Bill Moffat 

> There are better chemical than HMDS and TCMS.  For release agents you
> are looking for the highest achievable water contact angle.  Teflon has
> 13 fluorine molecules facing out and a contact angle of 120 degrees.
> With a heptadecafluoride there are 17 fluorine molecules facing out and
> a contact angle of 130 degrees.  Good news but the real secret is to
> totally dehydrate before the chemical sees the mold.  If it sees
> moisture it reacts with the moisture but breaks free later when it sees
> moist room air.  This gives erratic surface tension modification.  How
> big are your molds?  Bill