SURFACE-CHEMISTRY OF POLYIMIDE FORMATION ON CU(111)

We have investigated the adsorption and reaction of the monomers pyrom ellitic dianhydride (PMDA) and oxydianiline (ODA) to form the intermed iate amic acid and then polyimide adsorbed on Cu(111) using solventles s vapor deposition in ultrahigh vacuum. Unenhanced surface Raman spect roscopy was used to identify the adsorbed species. The initial reactio n of PMDA and ODA at 383 K created an amic acid ion that was bound to the surface via carboxylate and surface amide linkages. Upon heating t he intermediate acid to 473 K, polyimide was formed; it was bound to t he surface only via a surface carboxylate. The interfacial polymerizat ion produced only relatively short polyimide chains. The surface Raman spectrum of the amic acid was resonantly enhanced.