Positron annihilation and conductivity measurements on poly aniline

The positron lifetime spectra and electrical conductivities are measured for poly aniline as a function of protonation level ([H+]) from 10-7-100.8 mol/L). It is observed that the short lifetime τ1, which is related to electron density in bulk, decreases with the protonation level; the intermediate lifetime τ2 ≅ 360 ps, almost remaining constant, whereas its intensity I2 increases with increasing protonation level which is related to the conductivity of material. These results are discussed in terms of conducting island model