Josephson Effect in Metal - Polyimide - Metal Sandwich Structures
  We have observed that thin films of amorphous polyimide placed between two metallic electrodes become highly conducting with no applied electric field, and at a low pressure which was necessary only to achieve reliable electrical contact with the metallic electrodes. We observed for the first time a Josephson effect in a sandwich of a superconductor - polyimide film - superconductor. 
A.N. Ionov, V.A. Zakrevskii, J.M. Lazebnik, R. Rentzsch, V.M.   Svetlichny