Do you think it is possible to use some hydrophobic organic reagents, e.g., hydrophobic silane, to treat the surface of PAAm film? Or could you purchase this kind of film from company? 

To summarize you question

You have a coating of PMMA which results an advancing water contact angle smaller than 90°.

I guess your “solvent” is the dispersion medium used for the application?

Do you want to change the structure or to you want to change the PMMA itself?

Using a silane/siloxane results if possible in an additional film (your PMMA only contains some COOH groups).

I suggest using a copolymer or exchange the surface ester groups of your coating.

Article Analysis of silanes and of siloxanes formation by Raman spectroscopy

Thank you very much for your answers. To clarify, I need the hydrophobic film for use in a dry transfer of nanostructures. Hydrophobicity is necessary to ensure strong interaction between the structures (also hydrophobic) and the film. An additional film would be fine as long as it is hydrophobic and would stay attached to the PMMA. I do not think such a film can be bought from company.

I did not know about the possibility of treating with silane/siloxane. Does this mean I make a solution using a silane and spin-coat on top of my PMMA film? Or do I have to add this silane to the PMMA solution? Could you suggest a silane which would be appropriate for PMMA?

Since you don't make your own polymer, best way is the use of silanes.

be not confused on the big quantity available from suppliers, the best looks like trimethyl,(Mono) ethoxy silane. This monster isn't to toxic ( not more as your solvents for the PMMA), shut be soluble in then.

Try 2 to 5 % incorporated in your PMMA solution and let dry, check next day the hydrophobic character and if there are pin holes.

If pin holes, make a sole 10 % solution in EtOH and after coat.

There are even same silanes with Terbutane groups-but the prices too...

Good luck Roland

Dear Timofey :

The way to make hydrophobic PMMA film  suggested by Ronald Hildel - in my opinion - is most effective and very simple.

Best Regards,     Leonid

Timofey,

if there is still same Need to go further with your proyect, as providers of raw material, keep contact.

If all is glad  in your trials, please send same notices,

Greetings, Roland H.

Hi Timofey,

If the silane approach hasn't worked, you might try a reaction with 3-(perfluoro-7-methyloctyl)-1,2 epoxypropene. 

http://www.nature.com/pj/journal/v47/n1/abs/pj201491a.html

Best,

Darren