Nanostructured fluids confined into Highly Viscous Polymeric Dispersions as cleaning tools for artifacts: A rheological, SAXS, DSC and TOF-SIMS study

The development, and the structural and mechanical characterization of an new complex system composed by an oil-in-water microemulsion (μE) embedded in a aqueous 3D Highly Viscous Polymeric Dispersion (HVPD) of poly(vinyl alcohol) (PVA) cross-linked by borax, is here presented together with its possible implications in paintings conservation. The HVPD/μE was characterized by Small Angle X-Rays Scattering (SAXS), Differential Scanning Calorimetric (DSC) and rheology to obtain information about the mutual effect of the μE and of the PVA network on both the nanostructure of the μE, and on the mechanical behavior of the system. Experimental data indicate that the nanostructure of the μE is retained even in the presence of the PVA/borax network whose mechanical properties are enhanced by the presence of the nanofluid. The effect of HVPD/μE on organic molecules thin films of varnish coatings usually used on easel paintings, was studied by Attenuated Total Reflection Fourier Transform InfraRed spectroscopy (ATR-FTIR) and Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS). The results showed that an interaction occurred leading to the extraction of the organic molecules within the HVPD/μE. The applicative consequence was that the HVPD/μE complex fluid revealed itself to be a potential, very powerful and “green” tool for selective cleaning of easel paintings affected by artificial aged coatings, with very low environmental impact and leaving no residues onto the painting surface.