title: Characterization of a water-dispersible metal protective coating with Fourier transform infrared spectroscopy, modulated differential scanning calorimetry, and ellipsometry.
abstract: An ethylene-methacrylic acid copolymer, formulated by BASF as a waterborne suspension of its alkylammonium salt and used, among other applications, in art conservation as a temporary protective coating was characterized using Fourier transform infrared (FT-IR) spectroscopy aided by  modulated differential scanning calorimetry (MDSC) and ellipsometry. The thermal conversion of thin copolymer films from the freshly applied state, where carboxylic acid and carboxylate ion functional groups co-exist, to a purely acidic working state was spectroscopically followed. Transmission  mid-infrared data of the working state showed a 1 : 12 ratio of methacrylic acid towards ethylene units. The glass transition temperature (T(g)) in the same state was found at 45 °C. Copolymer films spin-coated on mechanically polished bronze and iron coupons  were characterized with transflection infrared spectroscopy and compared to corresponding transmission mid-infrared spectra of copolymer films spin-coated on silicon wafers. In the case of bronze coupons, evidence for interaction of the carboxylate ion with the copper substrate was obtained.  The chemical structure and the thermal behavior of the coating, as well as some implications on its protective capability towards iron and copper alloys, is discussed as this material has received considerable attention in the field of metal conservation and coatings.
authors.affiliation: Technological Educational Institute of Athens, Department of Conservation of Antiquities & Works of Art, Egaleo 12210, Greece. sboyatzis@teiath.gr
authors.forename: Stamatis C
authors.initials: SC
authors.lastname: Boyatzis
authors.forename: Antonios M
authors.initials: AM
authors.lastname: Douvas
authors.forename: Vassilike
authors.initials: V
authors.lastname: Argyropoulos
authors.forename: Amalia
authors.initials: A
authors.lastname: Siatou
authors.forename: Marilena
authors.initials: M
authors.lastname: Vlachopoulou