Assessment of aqueous cleaning of acrylic paints using innovative cryogels

Facilitating the conservation treatment of Eva Hesse’s Addendum through practice-based research, including a comparative evaluation of novel cleaning systems

“…The Nanorestore Gel ® Peggy series 10 was specifically developed within the NANORESTART project for the cleaning of contemporary works of art with textured or irregular surfaces. These gels are opalescent, physical hydrogels based on a poly(vinyl alcohol) polymeric network, synthesised through a freeze-thaw process [39][40][41][42]. Among the options available, Nanorestore Gel ® Peggy 5 consists of a blend of polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP) polymers, where the PVP provides enhanced retention properties [40].…”

“…These investigations were repeated using microFTIR-2D imaging which has lower detection limits (< 0.6 pg/pixel, 1 pixel = 30.25 µm 2 , as measured for PVA and PVP films on metallic Al surfaces) [40]. The presence of residues were explored via mapping characteristic absorption bands from each cleaning material, such as the axial deformation of C=O of enols (β-diketones) at 1530-1650 cm −1 for Xanthan gum; the silicone-methyl stretching band at ~ 1250-1260 cm −1 for the Shin-Etsu KSG-350z silicone emulsifier; the C=O stretching band of PVP at 1620-1670 cm −1 for the TT14 thin gel [40,41]. The cleaning efficacy of each system (applied as described in Table 2) was also evaluated via mapping the Si-O stretching band of kaolin, one of the constituents of the artificial soiling mixture, in the range between 1083 and 960 cm −1 (Additional file 1: Fig.…”

Easy-to-Make Polymer Hydrogels by UV-Curing for the Cleaning of Acrylic Emulsion Paint Films

“…Acrylic emulsion paints are made from water, acrylic monomers, stabilizers, thickeners, coalescing agents, pigments, and a wide range of additives that improve the paint’s properties [ 6 , 17 ]. The resulting film can become tacky at room temperature due to a low glass transition temperature (T g ), which triggers the adhesion of airborne dust [ 11 , 17 ]. Moreover, static charges and hydrophilic additives accumulated in the surface, such as surfactants, can attract and embed environmental soil [ 11 , 18 , 19 ].…”

“…Moreover, static charges and hydrophilic additives accumulated in the surface, such as surfactants, can attract and embed environmental soil [ 11 , 18 , 19 ]. Research carried out by a number of conservation scientists [ 13 , 14 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 ], identified the factors that influence the sensitivity of acrylic paint films to organic solvents and water-based cleaning systems [ 6 , 11 ]: additive migration, swelling of the paint film, and re-transport of solubilized matter through the porous matrix of the artifacts during the cleaning procedure [ 12 , 13 , 14 , 15 ] are, among other factors, only a few of the obstacles ahead.…”

“…Some researchers proposed thickeners, such as cellulose derivatives and polyacrylic-based formulations [ 33 ], to enhance the control of solvent diffusion by increasing the viscosity of the liquid [ 15 , 16 , 33 , 34 ]. However, the residue in thickened systems is still a challenge that has not been resolved [ 17 , 35 , 36 ]. Rigid gels, which can be classified as physical or chemical, according to their bonding nature [ 15 , 37 ], were proposed as residue-free confining systems.…”