[meysam_rb]

I want to bond Hydroxyl group on Silicon (Si-OH).
Does anybody have any experiences about that?

[cpncoop]

There is literally tons of literature on this.  Easiest way in my opinion is to activate the end you want to bond by converting it to the mesylate, then applying it to the surface....  But you can do it many, many other ways as well...

[doc30]

Treat with strong caustic, rinse, treat with acetic acid and rinse again. You will have lots of Si-OH, assuming you are dealing with a silica or silica-like surface. Si-OH is fairly reactive with other Si-OH, epoxy groups or even alcohols in the presence of a catalyst.