Hi Daniel,

    Here are my thoughts, for what they are worth...
1. It appears that you don't have an control over the smoothness. It
would be nice to know what it is (using an AFM), but probably not
critical.

2. I'm not familiar with the Harrick plasma cleaner, but it sounds
more like an asher than an RIE. I believe you might get "more"
activation if you use a parallel plate type reactor at around 100 W. I
would probably try a pressure on the lower end because it would result
in the plasma particles impacting the target surface with higher
energy -- leading to arguably better activation.

3. I would also try the RCA-1 dip (75 C for 30-60 s, then blow dry)
after the plasma since it's quick and easy to do.

4. Applying pressure to the bonded samples probably does not hurt of
the pressure is applied evenly and consistently.

5. I can't say for sure about the silanols and solixanes for MgF
surfaces after activation. I would guess that they are specific to Si/
SiOx surfaces, but hey, you never know. If all that fails, try a F
containing plasma.

I'd be interested in hearing how it works out!

Best of luck!

Felix


On Jun 29, 2010, at 7:31 PM, Danny Gossett wrote:

> Hi Felix
>
> 1. I don’t know how to assess its smoothness.  The military
> specifications it adheres to don’t seem to quantify this either.  I
> agree the compliance should help; I can see the two surfaces come into
> contact after pressure.
>
> 2. We use a Harrick Plasma Cleaner (PDC-001) at 30W for 20-30 seconds
> for bonding PDMS to glass.  We activate both surfaces at the same
> time.  I replicated this protocol when I attempted bonding to MgF
> instead of glass.  It is air plasma; we also have access to oxygen
> plasma and could try this at higher powers.
>
> 3. With PDMS to glass the surfaces wick together after a point
> pressure.  With the PDMS to MgF I needed to apply some pressure by
> hand for the surfaces to meet.  After this they appeared to remain in
> contact.  Only after testing the bond did I find that there was none.
> Typically I apply no pressure after bringing the surfaces into contact
> and bake at 65C for at least 5 minutes.
>
> 4. I think I’ve read the plasma treatment creates silanols on both
> glass and PDMS and these condense to form the bond.  The plasma
> cleaner in our nanolab also offers carbon tetrafluoride.  Perhaps I
> could try this.
>
> Daniel

Felix Lu
felix_lu@yahoo.com