Atomic force microscopy as a valuable tool in an innovative multi-scale and multi-technique non-invasive approach to surface cleaning monitoring

To monitor and analyze the effectiveness of new cleaning formulations, using a combination of ionic liquids ([BMIM] [BF4] and [EMIM] [EtSO4]) and enzymes (three different proteases E.C.3.4.), we adopted a novel multi-scale non-invasive approach based with different instruments: the stereomicroscope (SM), the optical microscope (OM) with visible and fluorescence light, atomic force microscope (AFM) and scanning electron microscope (SEM). The combinations of these techniques allowed an extensive and complete characterization of the surface materials and were successfully applied for monitoring the cleaning process. Although the results showed in this work were obtained for this specific treatment, of removing proteinaceous varnish layer from documented reconstructions, it was demonstrated that the AFM monitoring protocol can be widely applied on everyday situations in the conservation science.