Polyimide with special bonding properties to metal, esp. e.g. gold - prepd. by vapour deposition of pyromellitic dianhydride and di:amino-di:phenyl di:sulphide on a metal substrate, followed by imidisation

摘要

Polyimide of formula (I) is new; n = 30-35. USE/ADVANTAGE - The invention provides a new polyimide with the advantages of other polyimides, but which also undergoes defined coordinate bonding with metal substrates with cleavage of the S-S bond, resulting in very good adhesion to metals such as Au, Ag, Fe etc. without using an additional coupling agent, as required e.g. for electronics applications. In an example, a clean gold substrate was immersed for 10 hrs. in a 1-mM soln. of DAPS in ethanol, then rinsed under nitrogen with ethanol; the coated substrate was placed in a vacuum chamber and coated with PMDA and 4,4'-oxydianiline (ODA) by vapour deposition from 2 Knudsen cells, and the system was then imidised by heating at 250 deg. C for several hrs. The PMDA/ODA polyimide film, which does not normally react with gold, was coordinatively bonded to the surface via the DAPS mols.