Interaction behaviour of spun films of poly [3-(6-methoxyhexyl)thiophene] derivatives with ambient gases

The effects of saturated organic vapours on spun thin films of the conjugated polymer of regioregular poly [3-(6-methoxyhexyl)thiophene] molecules were investigated by using the surface plasmon resonance technique in a Kretschmann type optical arrangement. The refractive index of the untreated polymer film is found to be 1.505 irrespective of the film speed. The swelling of the film occurs due to benzene exposure and a small change of refractive index is also observed, possibly due to the influence of benzene on the orientation ability of the polymer. The vapour response is related to the magnitudes of the vapour dipole moments and their sizes. The polymer suffers irreversible degradation due to the continuous exposure to ozone concentrations in the ppb range.