good one I forgot mica althogh I prefer not transparent substrate,

Thanks

If the above surface is not hydrophilic enough for you (Mica) then you need to put it in some type of solution containing PTFE to increase your wettibility

Mica, but if you dont want transparent, use Biotite instead!!!

Brittle materials with high hardness will be a good choice if you want

Thanks, Mica is not that much hydrophobic

You should run some experiments and use statistical software such as DOE to optimize your condition