[FOULSER P.F.G.]

FOULSER P.F.G.  asked the Naked Scientists:
   
Dear Chris,

Firstly, thanks for such a great show!

Secondly, I have a question about electrostatic forces acting between solid surfaces. Is it possible to have two surfaces so perfectly flat that, when juxtaposed, they stick to each other purely through their electrostatic forces? Have these ever been made?

Many thanks

Pete

What do you think?

[graham.d]

Yes, though there maybe other forces acting. The electrostatic forces that can occur are Van-der-Waals forces (please lookup on Wikipedia for a beter description than I can give). Now it is also thought that there can be another force (quantum mechanical in nature) causing such attraction; this is the Casimir Effect.

Whichever the dominant cause, two flat surfaces are attracted and such techniques are used in the semiconductor industry to effectively join two thin wafers of a silicon crystal. This is done in some manufacturing of devices where it is required to add Micromechanical structures to an existing processed semiconductor wafer.