The Migration of Surfactants in Acrylic Emulsion Paint Films

Artists’ acrylic emulsion paints are formulated using many constituents. Non-ionic surfactants such as those based on polyethylene oxides (PEOs) have been found in acrylic paint films, which may function both to stabilize the acrylic polymer in the aqueous emulsion phase and to aid pigment wetting and dispersion. PEOs that remain relatively mobile in the dried polymer film may affect surface gloss in a painting, the extent and nature of dirt pick-up, and the sensitivity of the film to methods used for surface cleaning. The present study aimed to characterize the migration of PEO surfactant in selected contemporary acrylic emulsion paints made by Winsor & Newton and Golden Artist Colors, and to assess the effects of swab-rolling with water and non-polar solvent, used for surface cleaning paintings, on dried and light-aged paint films. Methods for characterization included light microscopy (LM) and scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and matrix assisted laser desorption/ionization-mass spectrometry (MALDI-MS). The results show that PEOs, present as characteristic aggregates at the surface of films, are light-sensitive, hygroscopic, and readily soluble in water applied using a swab in cleaning tests. These findings may be relevant to the methods used for the surface cleaning of acrylic paintings.