Improvement of the Uniformity and Electrical Properties of Polyaniline Nanocomposite Film by Addition of Auxiliary Gases during Atmospheric Pressure Plasma Polymerization

The morphological and chemical properties of polyaniline (PANI) nanocomposite films after adding small amounts of auxiliary gases such as argon, nitrogen, and oxygen during atmospheric pressure (AP) plasma polymerization are investigated in detail. A separate gas-supply line for applying an auxiliary gas is added to the AP plasma polymerization system to avoid plasma instability due to the addition of auxiliary gas during polymerization. A small amount of neutral gas species in the plasma medium can reduce the reactivity of monomers hyperactivated by high plasma energy and prevent excessive crosslinking, thereby obtaining a uniform and regular PANI nanocomposite film. The addition of small amounts of argon or nitrogen during polymerization significantly improves the uniformity and regularity of PANI nanocomposite films, whereas the addition of oxygen weakens them. In particular, the PANI film synthesized by adding a small amount of nitrogen has the best initial electrical resistance and resistance changing behavior with time after the ex situ iodine (I-2)-doping process compared with other auxiliary gases. In addition, it is experimentally demonstrated that the electrical conductivity of the ex situ I-2-doped PANI film can be preserved for a long time by isolating it from the atmosphere.

Automated summary

The effect of adding small amounts of auxiliary gases to PANI nanocomposite films during plasma polymerization at atmospheric pressure was investigated. The addition of argon or nitrogen significantly improves the uniformity and regularity of the films, while adding oxygen weakens these properties. PANI films synthesized with a small amount of nitrogen show the best electrical resistance and resistance changing behavior after external I-2 doping compared to other gases.