An AFM contribution to the understanding of surface effects caused by ageing and cleaning on acrylic glass. The Shadows by Lourdes Castro, a case study

Atomic Force Microscopy (AFM) was used to study the ageing and cleaning effects on the surface of acrylic glass sheets (PMMA) like the ones used by the Portuguese artist Lourdes Castro. Measurements were done in transparent (colourless and blue) samples. The samples were aged in a SolarBox; cleaning and polishing products, similar to the ones applied by the artist, were used. From the AFM images the craze/scratch phenomena in the pristine samples surface was confirmed. The experiments led to an increase of the surface roughness, more pronounced for the polished samples due to the presence of granular features. These modifications are due to the interaction of the acrylic sheets with the polishing products, which seems to be stronger in the coloured samples. These findings are useful to define the best strategy to prolong the longevity of such materials, in particular the works of art created by Lourdes Castro. Copyright (C) 2010 John Wiley & Sons, Ltd.