I was wondering what happens to the electron after it leaves it's valence shell and strikes a stable valence shell; in an insulating material? I realize that the energy from the strike, is absorbed by the atom that was struck and that these electrons do not 'break free'...so what happens to the electron that struck them?
Atoms whose outer shells are not filled will take on additional electrons. ie., the atoms in the insulating material will absorb the electron into it's own outer ring atomic structure. It has to do with the "octet theory" of the Bohr model.
On the other hand, if you are talking about electron excitement, where one free electron frees another, as in a laser light system, again, a layer of the correct insulation would prevent that.
When an electron collides with an atom or ion, it may
• excite the atom/ion (I + e → $I^∗$ + e)
• ionize the atom/ion (I + e → $I^+$ + 2e)
• scatter inelastically (I + e → I + e + γ)
• recombine radiatively (I + e → $I^−$ + γ)
• recombine dielectronically (I + e → $I^−∗$)
This memo will focus on the final process, where an electron recombines with the ion in an excited state and excites a second electron while doing so. The ion is left in a highly excited state, which may then autoionize (thereby inverting the dielectronic recombination and converting the process into a simple scattering event) or it may radiatively decay when one of the excited electrons radiatively decays, creating a satellite line. A satellite line is so named because it will be at a slightly longer wavelength than the normal transition from an electron in that energy level. The due to the recombined electron which is also in an excited level.