HIGHLY REFLECTIVE POLYIMIDE FILMS CREATED BY SUPERCRITICAL-FLUID INFUSION OF A SILVER ADDITIVE

Supercritical fluid infusion of a silver-containing additive [1,5-cycl ooctadiene silver(I)-1,1,1,5,5,5-hexafluoroacetylacetonate] into a ful ly cured polyimide was achieved with moderately high-density carbon di oxide at 110 degrees C for the first time. The polyimide was derived f rom 4,4'-oxydianiline and 3,3',4,4'-benzophenone tetracarboxylic acid dianhydride. After infusion for approximately 60 min, the resulting fi lm was then recured at 300 degrees C in air. During this time, a silve r mirror formed on both film surfaces. The nature of the silver and it s distribution within the film and on the film surface were establishe d via microscopy and surface analysis techniques. (C) 1997 John Wiley & Sons, Inc.