Hi,

We have free (released, untethered) blocks that must be free to slide over a
surface.  Currently, the blocks are SU-8, the surface is glass, and they are
immersed in a saline solution.   Typically, the blocks attach themselves to
the glass substrate and become difficult to slide. I am looking for a way to
reduce stiction of this system.  Do you have any suggestions, or experience
with something like this?  Any idea what the predominant force is in a
system such as this?

Some solutions I have in mind are:
1. low-friction coating on substrate.  fluorinated films seem to be helpful
in stiction in air but do they help under water?
2. reduce charge.  if electrostatic charge is the predominant attractive
force, would dissipating the charge help. What is the best way to do this?
3. different materials - while su-8 and glass are currently preferable,
other materials may also be considered
4. ultrasonic stage - i've read that placing the device on an ultrasonic
vibrational platform may reduce stiction, but I've only seen it in reference
to systems in an air medium.

Does anyone have experience with any of the solutions listed above?

thank you for any suggestions and advice,

Evan