James Rancourt

Chemistry of the Interface Between Aluminum and Polyester Films

Abstract It has been observed that the adhesion between vacuum-evaporated aluminum and poly(ethylene isophthalate-co-ethylene sodium sulfoisophthalate) copolymer is approximately five times greater than the adhesion between vacuum-evaporated aluminum and biaxially-oriented poly(ethylene terephthalate) film. To describe the interface between the aluminum and these polymeric substrates, thermoanalytical, spectroscopic and microscopic techniques have been applied. Definite changes in surface elemental composition and chemical functionality occur upon metallization of the polymer films. Aluminized samples contained two new oxygen functionalities; one due to the aluminum oxide and the other due to an organoaluminum species. Thermal degradation, as may occur during vacuum evaporation, would be expected to yield a carboxylic acid endgroup and a vinyl endgroup for each chain scission reaction that occurred. Reaction of aluminum with these carboxylic acid endgroups is thought to be responsible for the organoalumin...

Chemical factors that influence the production of conductive and/or reflective silver-doped polyimide films

ABSTRACT Doping a poly(amide acid) resin with a silver containing additive (1,5-cyclooctadiene-hexafluoroacetylacetonato)-silver(I) [Ag(COD) (HFA)] resulted, after thermal cure, in either a highly reflective or highly electrically conductive polyimide film. The combination of monomers, which render films with low Tg (~210°C), and contained sulfur, produced films with surface resistance in the range 101–103 ohms. On the other hand, films with specular reflectivity (relative to a silver mirror) in the range of 65–48% were obtained using both high Tg polyimides and polyimides void of sulfur in the polyimide backbone with low Tg. Our understanding regarding the structure-property relationship on these polyimide films and also the characterization of the doped-films are discussed.

Polyimides Doped with Silver-II: Surface Conductive Films

Polyimides are used for a wide range of applications in areas such as integrated electronic circuits and aerospace devices that require excellent dielectric properties, high temperature stability and chemical inertness (1). On the other hand, some applications require low electrical resistivity and high reflectivity which are characteristics that are more typical of metals. In the attempt to synthesize materials with unique combinations of properties, metal-containing polymeric composite material (2,3) have been suggested as candidates. Insulating polymers possessing desirable technological properties may be rendered conductive by mixing with conductive particles such as carbon black, metal powders, flakes or fibers and metal coated particles, but in many cases high loading levels have been necessary which spoil the polymer’s properties. The approach of Taylor and co-workers (4-10) has been to dissolve additives (metal salts and organometallic complexes) into a poly (amide acid) solution. The resulting films of pre-polymer upon thermolysis undergo both imidization and metallization. Appropriate processing and the correct choice of monomers yield reflective and/or conductive films in which the polymer’s properties are basically maintained (11, 12). Enhanced surface reflectivity has been obtained with copper (13), gold (14), and silver (15-18, 11) compounds; while palladium, platinum (19), and tin (20) salts have improved surface electrical conductivity.