Doping of thin plasma polymerized aniline films

Summary form only given. Polymers can be used as conductors of electricity and as "smart" materials, which change one or more properties when activated by an electrical signal. Applications include control of electrostatic charge, batteries, fuel cells, drug delivery devices, optical switching, optical displays, capacitors, microactuators, field-effect transistors and light emitting diodes. The electroactive properties of plasma polymerized aniline films have been studied recently by others. In our work, we have fabricated plasma polymerized aniline resistors. To measure the resistivity of the film, gold electrodes were sputtered onto ceramic substrates. For comparison purposes, one electrode structure remained "blank" without further processing. Plasma polymerized aniline film with thickness 0.2 /spl mu/m was deposited over the remaining electrode structures. These resistors were annealed in a nitrogen environment at 125 C for 4 hours. While the plasma polymerized aniline film on one resistor remained undoped the film on another was doped by immersion in a 1 molar HCl solution for 7 hours. Doping was followed by vacuum drying. Resistor values for the blank electrode structure, tor the resistor with undoped film and for the resistor with doped film were measured from the slope of volt-ampere characteristics recorded with a Keithley 617 Electrometer. The undoped film had a conductivity less than 4/spl times/10/sup -2/ s/cm while the film doped with the liquid HCl treatment had a conductivity of 4/spl times/10/sup -10/ to s/cm, a result that is consistent with earlier work by Gong et al. (1998).