Well, PANI is readily reduced / oxidised electrochemically, so unless you have need for testing under some particular conditions, I would recommend using a relatively small (approx. 0.1V) potential difference, so as not to affect its doping (oxidation) state (as its conductivity is very strongly dependent on that).

We usually apply 3V as in put voltage in our lab.

Normally with PANI it is recommended to reduce the voltage as much as possible. But in your case, since it is a blend and a thick layer, I would recommend you to go for (-10V to +10V) with one sample and then narrow your voltage range according to the result.

thanks for sharing your valuable experience