Streaming electrification of a dielectric liquid through a glass capillary

The flow electrification phenomenon of a liquid flowing along a solid has been studied for long time. This electrical phenomenon is due to the convection of charges coming from the electrical double layer at the solid/liquid interface. The purpose of this paper is a contribution to understand the formation and the description of the electrical double layer at a dielectric liquid/dielectric solid interface. Flow electrification experiments of heptane through a glass capillary have been conducted in the case a nonfully developed double layer and for a diffuse layer thickness nonnegligible compared to the capillary radius. Then a theoretical model allows computation of the values of the space charge density at the wall in function of the liquid conductivity. The results show a behavior similar to the Van der Minne Evolution. Furthermore it is demonstrated that the relaxation time was not enough to describe the diffuse layer formation.