Microscopic and macroscopic transport properties of polyaniline: effect of chain orientation and hydration

Proton relaxation times T1 and DC conductivity have been measured on unstretched and stretched polyaniline films, in the dried and the hydrated states. It is shown that polaron motion is highly anisotropic at the chain scale and that stretching increases interchain hoppings. On stretched films, hydration induces an increase of the conductivity but a decrease of its anisotropy. The data are accounted for in a simple model which links the macroscopic transport properties to the microscopic ones.