Interactions of Electroless Catalysts with Photo‐Oxidized Polymer Surfaces

Abstract

The surfaces of poly(styrene) (PS) and two polymers containing styrene, poly(styrene‐acrylonitrile) (SAN), and poly (acrylonitrile‐butadiene‐styrene) (ABS) were photo‐oxidized with 254 nm light and then treated with Pd‐ or Ag‐based electroless catalysts. These photo‐oxidized surfaces poisoned the Pd catalysts, hence inhibiting electroless metal plating, but the Ag‐based catalyst resisted deactivation by the modified surface. Results from x‐ray photoelectron spectroscopy (XPS) indicate that catalyst poisoning is due to photochemically produced carbonyl groups on the polymer surfaces, but show no spectroscopically significant change in the electroless catalysts. Treating irradiated polymers with alkaline solution restores platability and correlates with a loss of surface carbonyl groups by way of an alkaline decarbonylation reaction. Six electroless baths (two Cu and four Ni) were examined; the catalyst deactivation effect is independent of bath chemistry.

Interactions of Electroless Catalysts with Plasma‐Oxidized Surfaces of Polystyrene‐Based Resins

“…Specimens 0.25 x 13 x 38 cm were cut from 0.25 x 75 x 100 cm injection-molded plaques of gray PG-298 poly(acrylonitrile-butadiene-styrene) (ABS) (Monsanto, St. Louis, Missouri), Tyril 2000 clear poly(styrene-acrylonitrile) (SAN) (Dow Chemical USA, Midland, Michigan), and 1-G3C2 (polystyrene) (PS) (Amoco Chemicals Company, Chicago, Illinois). PS and SAN specimens were abraded and ABS specimens were etched in the manner previously described (12), then rinsed with 2-propanol, and then with distilled water. XPS examinations were done using the instrument and techniques previously described (12).…”

“…PS and SAN specimens were abraded and ABS specimens were etched in the manner previously described (12), then rinsed with 2-propanol, and then with distilled water. XPS examinations were done using the instrument and techniques previously described (12).…”

“…Sharp (1), Chow et al (5), Schlesinger et al (6,7), and Baylis et al (8)(9)(10)(11) examined methods by which the electroless catalysts were photochemically activated (9) or deactivated (5). Their work led to examinations (12) of the effect of oxidized substrates on the activity of electroless catalysts.…”

“…These interactions may be utilized to achieve selective deposition of metals onto polymers. For instance, chemical groups that poison electroless catalysts can be incorporated in the substrate (2,3) or synthesized by photo-oxidation of some surfaces containing polystyrene (reactions [1]- [3] (12)(13)(14)). The poisoning effect of the photo-oxidation process can be reversed by soaking the photo-oxidized polymers in an alkaline solution before catalysis (reaction [4]).…”

“…The poisoning effect of the photo-oxidation process can be reversed by soaking the photo-oxidized polymers in an alkaline solution before catalysis (reaction [4]). X-ray photoelectron spectroscopy (XPS) measurements indicate that the catalysts are poisoned by photochemically produced surface carbonyls (probably carboxylates) which are cleaved by the alkaline soak (12) sub + cat ~ sub-cat (platable) [1] hy sub + 02 --> sub ~ (photo-oxidized) [2] sub s + cat ---> subs~-cat (unplatable) [3] sub ~ + OH----> sub (platable) cat = electroless catalyst sub = PS, SAN, or ABS substrate (unmodified) sub ~ = photo-oxidized substrate [4] The interaction between a photo-oxidized surface and the electroless catalyst seems to be fairly general for Pdbased catalysts. For instance, irradiation produces surfaces which deactivate (12) a two-step catalyst, produced by sequential exposure of the substrate first to SnC12 and then to PdC12 solutions, and a colloid catalyst (15).…”