The removal of polymeric films using amphiphilic solutions is of great interest for colloidal science and for various technological applications in which adhesion phenomena are involved such as conservation science. Understanding the key steps of the cleaning mechanism is the main hurdle towards a more efficient design of these complex fluids; however, due to huge variability of the real substrates and of the nature of the polymeric layer, the factors affecting the interaction between the fluid and the film are not completely understood.
We propose here the innovative use of optical techniques such as confocal laser scanning microscopy and surface methods like atomic force microscopy to highlight the role played by each component of the fluid during the removal process and its main steps. In particular, we focus on the interaction between an ethylmethacrylate/methylacrylate co-polymer and a water/non-ionic surfactant/2-butanone ternary system; we also investigate the behavior of a ternary system containing an anionic surfactant (SDS) to understand the effect of surfactant's chemical nature and of the microstructure of the aggregates on the cleaning mechanism.
Our results indicate a cooperative mechanism between the organic solvent and the surfactant: the solvent rapidly dissolves the outer layers of the polymer film; meanwhile, surfactant micelles penetrate through the polymeric chains inducing conformational changes and promoting the diffusion of solvent molecules. Moreover, the amphiphile decreases the interfacial energy thus polymer removal occurs; the kinetics and the efficiency of the cleaning process can be tuned changing its chemical nature.
M. Baglioni, R. Giorgi, D. Berti and P. Baglioni. Smart cleaning of cultural heritage: a new challenge for soft nanoscience. Nanoscale, 2012, Vol. 4, 42-53.
debora.berti@unifi.it
