Nanofluids and chemical highly retentive hydrogels for controlled and selective removal of overpaintings and undesired graffiti from street art

One of the main problems connected to the conservation of street art is the selective removal of overlying undesired graffiti, i.e., drawings and tags. Unfortunately, selective and controlled removal of graffiti and overpaintings from street art is almost unachievable using traditional methodologies. Recently, the use of nanofluids confined in highly retentive pHEMA/PVP semi-interpenetrated polymer networks was proposed. Here, we report on the selective removal of acrylic overpaintings from a layer of acrylic paint on mortar mockups in laboratory tests. The results of the cleaning tests were characterized by visual and photographic observation, optical microscopy, and FT-IR microreflectance investigation. It was shown that this methodology represents a major advancement with respect to the use of nonconfined neat solvent

Smart cleaning of cultural heritage: a new challenge for soft nanoscience

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Calamità naturali e assicurazione: elementi di analisi per una riforma

Private insurance markets provide insufficient coverage for risks coming from natural disasters. We argue that in such markets the typical market failure is mainly due to reasons other than asymmetric information. More specifically, the low probability of a disaster, together with the height of the economic damage normally involved and the strong correlation among individual risks raise the insurers’ and lower the potential clients’ reservation price. The solution recently provided within the market (the CAT bonds) is interesting but unsatisfactory. Therefore the intervention of the public sector is needed. After analyzing the experience of some countries (USA, France, Spain, Switzerland), we propose a reform plan for Italy that avoids the discretionary ex post public intervention, allows an inter-temporal risk diversification, and avoids the waste of resources in risk selection (a typical feature of the private provision of insurance).Insurance, Natural disasters, Public provision of services

Nanostructured Surfactant-Based Systems for the Removal of Polymers from Wall Paintings: A Small-Angle Neutron Scattering Study

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Removal of acrylic coatings from works of art by means of nanofluids: understanding the mechanism at the nanoscale

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Twin-chain polymer networks loaded with nanostructured fluids for the selective removal of a non-original varnish from Picasso's "L'Atelier" at the Peggy Guggenheim Collection, Venice

Abstract This paper reports on the evaluation of a polyvinyl alcohol (PVA) "twin-chain" polymer network (TC-PN) combined with an oil-in-water nanostructured fluid (NSF) for the removal of a polyvinyl acetate (PVAc) varnish. Small Angle X-ray Scattering, Confocal Laser Scanning Microscopy, and Fluorescence Correlation Spectroscopy showed that the structure of the gel and the NSF are only minimally altered by loading the fluid into the gel. The NSF is partially free to diffuse through the network, but also interacts with the gel walls. During the cleaning, the dynamics of the fluid at the gel-substrate interface are controlled by the osmotic balance taking place among the interconnected pores. These features grant effective and controlled cleaning performances. The case study identified for this research is Pablo Picasso's The Studio (L'Atelier, 1928), one of the masterpieces in the Peggy Guggenheim Collection, Venice (PGC). In 1969 the oil painting, originally unprotected, was wax-lined and then varnished using a PVAc varnish. Over the years, the white shades of the painting have been compromised by the yellowing of the varnish and soiling of deposits. On painting mock-ups, the NSF-loaded hydrogels allowed the swelling and softening of PVAc varnish and wax layers, which were then removed with gentle mechanical action. Effective varnish and wax removal at the micron scale, and the absence of residues from the cleaning system (gel and NSF), were confirmed by Fourier Transform Infrared Spectroscopy (FTIR) 2D imaging. The effective and safe removal of the aged PVAc varnish and wax layer from the surface of the painting was then carried out using the same cleaning protocol successfully tested on the mock-ups, setting the NSF-loaded PVA TC-PNs as robust and reliable tools for the cleaning of sensitive works of art