Properties of the Photon Emission Accompanying the Peeling of a Pressure-Sensitive Adhesive

During the peeling of pressure-sensitive adhesives, it is well known that visible light is emitted from the region near the detachment zone. This photon emission due to adhesive failure is a unique form of triboluminescence. In this paper, we further investigate the properties of this light from the peeling of a filament tape with a natural rubber-resin adhesive from its backing at various peel speeds. We show conclusively that small electrostatic discharges are the major source of this radiation. Total intensity vs time measurements show that the light consists of very intense bursts with typical duration of 50 ns which frequently induce additional discharges for times as long as 50—100μs. Time resolved spectra of these emissions show them to be dominated by the line spectrum of molecular nitrogen for both the initial burst and those that follow in the next 0.1—100μs. Thus, the “after-emission” is not due to phosphorescence of the polymer(s), but due to these additional electrostatic discharges.