We report on the swelling process in gold-doped teflon-like films as a func
tion of metal concentrations. The film thickness variation, measured in low
-pressure acetone vapour using an ellipsometric technique, shows, with a ra
nge of 0.001-9 mbar, a linear increase in gold content. This trend disappea
rs for metal percentages near to the percolation threshold, an effect which
is also evident from the time evolution of the swelling process at constan
t pressure. PACS: 07.07Df; 81.15Cd; 83.85Gk.