Four experiments were conducted to study the macroscopic consequences of electrostatic interactions. These experiments included such varied topics as peeling tape and mica, crushing mica and dragging a metal tip on a semi conductor.;Contact electrification is an equilibrium process that can generate very high charge densities. Subsequent sudden separation of the surfaces can lead to non-equilibrium processes that have remarkable effects. One of them is the main topic of this thesis: the generation of as many as 2x105 X-rays/s (typically 15keV in energy and ∼2ns in duration) during the peeling of adhesive tape in vacuum.;X-rays were also found during the cleavage and crushing of brittle crystals in vacuum. In the last investigation presented in this thesis, friction control between a metal tip and a wideband semiconductor is achieved by applying a voltage between them. Reduction of up to 80% of the friction is found in this outstanding effect that may have its roots in the role of electrostatics in the adhesion of solids.
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