Corrosion prevention capability of polyaniline (emeraldine base and salt): An XPS study

Conference · Fri Dec 01 04:00:00 EST 1995

OSTI ID:126997

Jasty, S; Epstein, A J ^[1]

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1. Ohio State Univ., Columbus, OH (United States)

There has been a keen interest in the use of polyaniline coatings for the corrosion protection of Fe and its alloys. To date, the primary focus has been on the doped form of the emeraldine oxidation state; also, the polyaniline has been applied, electrochemically or chemically, as an overcoat on the metal. In the present study, the surface sensitive XPS technique has been applied to investigate (1) the effectiveness of the neutral emeraldine base as well as the doped emeraldine hydrochloride forms of polyaniline in corrosion inhibition and (2) the ability of a polyaniline undercoat in providing corrosion protection by passivating the exposed metal surface. Here 350{Angstrom} and 70{Angstrom} thick Fe was sputter deposited onto the polyaniline and control polymer (non-electroactive) substrates and exposed to different environments. We conclude that an undercoat of the neutral emeraldine base form of polyaniline passivates the outer metal (Fe) surface with a thin ({approximately} 30-50{Angstrom}) oxide layer of mainly hematite (Fe{sub 2}O{sub 3}) and that the passivation mechanism has an electronic origin. In contrast, Fe sputtered onto doped emeraldine hydrochloride forms a thicker oxide layer with a distribution of oxidation states, effectively providing much less corrosion protection.

• OSTI ID: 126997
• Report Number(s): CONF-950402--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CORROSION PROTECTION
IRON ALLOYS
ORGANIC POLYMERS
POLARIZATION