Condensation coefficients of Ag on polymers

Using a novel very sensitive radiotracer technique, we have measured the co ndensation coefficient C of Ag on several polymers. C shows an extreme vari ation ranging from close to unity for polyimide to values as low as 0.002 f or Teflon AF(TM) at room temperature. C decreases strongly at elevated temp eratures and exhibits a drop somewhere below the bulk glass transition temp erature. The observed angular distribution of reemitted atoms does not depe nd on the angle of incidence and has a cos theta form. This, among other ar guments, suggests them to be adsorbed at the surface prior to reemission. N ucleation, studied on a polycarbonate, turned out to take place at preferre d sites.