Light emission due to peeling of polymer films from various substrates

The intensity of the light which is emitted when polymer films are peeled mechanically from various substrates under varying conditions of vacuum was measured by a photomultiplier, amplifier, and pen‐writing oscillograph combination. The wavelength of the emitted light depends upon the sign of static charge generated on the surfaces of the film and the substrate by peeling. In the PVC‐glass sample system, the radiation consists of two bands of light, namely a shorter band (∼4900 Å) and a longer one (5200–5900 Å), but in other sample systems (e.g., PVC–copper, PVAc–glass), only the shorter band was observed. The latter band appeared at the higher degree of vacuum. Comparing these bands with discharge spectra of nitrogen gas and using various substrates, it was proved that the light of the shorter band can be attributed to the light of gas discharge and that of the longer one, to the light of glass luminescence. Generally speaking, the intensity of the light of the longer band is weaker than that of the shorter one. Total intensity of light changes with peeling speed and reaches a saturated value. This type of saturation may be interpretable if the streamer process is taken into consideration as a mechanism of electrostatic discharge. Total intensity of light depends also upon the pressure in the peeling chamber. At pressures of 10 −2 –10 −3 mm Hg, the total intensity of light becomes minimum. This phenomenon is interpreted as a change of discharge potential according to Paschen's law under the condition of constant width of discharge gap.