Ion Track Technology

PhysicsConsult

Reimar Spohr

PostHeaderIcon Abstract

Pore geometry of etched ion tracks in polyimide. C. Trautmann, W. Brüchle, R. Spohr, J. Vetter, N. Angert. Nuclear Inst. and Methods in Physics Research, B 111 (1996) 70-74.

Tracks of energetic heavy ions in the polyimide Kapton were etched in a NaOCl solution. It was found that the pH value of the etchant plays a crucial role for the selectivity of track etching. The bulk etching rate νb increased exponentially with pH. From the temperature dependence of the bulk etching rate an activation energy of Ea = 0.74 eV was deduced. In contrast to νb, only a slight and linear increase with pH value was observed for the track etching rate νt. As a consequence, the etch ratio νt/νb can be adjusted over one order of magnitude by controlled varying the pH of the etchant. This is a new way to tailor the pore geometry from nearly cylindrical to funnel-shaped pores.