Colloid and Materials Science for the Conservation of Cultural Heritage: Cleaning, Consolidation, and Deacidification

Abstract

Serendipity and experiment have been a frequent approach for the development of materials and methodologies used for a long time for either cleaning or consolidation of works of art. Recently, new perspectives have been opened by the application of materials science, colloid science, and interface science frameworks to conservation, generating a breakthrough in the development of innovative tools for the conservation and preservation of cultural heritage. This Article is an overview of the most recent contributions of colloid and materials science to the art conservation field, mainly focusing on the use of amphiphile-based fluids, gels, and alkaline earth metal hydroxide nanoparticles dispersions for the cleaning of pictorial surfaces, the consolidation of artistic substrates, and the deacidification of paper, canvas, and wood. Future possible directions for solving several conservation issues that still need to be faced are also highlighted.

Nanotechnologies for the restoration of alum-treated archaeological wood

“…In this way, it is possible to neutralize the acidity of the treated wood, and the alkaline reserve is expected to grant long-term protection to wood. Experiments performed at CSGI showed that archaeological wood treated with nanoparticles exhibited pH values granting long-lasting protection [11][12][13]. Furthermore, differential thermogravimetric analysis (DTG) carried out on wood samples treated with nanoparticles from Vasa has shown that nanoparticles increased the resistance of wood towards thermal degradation.…”

Le analisi spettroscopiche sul Diario spirituale di Sant’Ignazio in occasione del suo restauro

“…Per evitare l'uso diretto di mezzi acquosi, per la rimozione del velo di seta nel restauro degli Esercizi si è ricorsi alla applicazione di idrogel di gellano, abbastanza ritentivo da non bagnare il foglio ma capace di rilasciare vapore acqueo evitando il passaggio del solvente liquido nel foglio e la conseguente migrazione di ioni. Successivamente, si è adottato un trattamento deacidificante basato sull'applicazione di gelatina addizionata di nanoparticelle di idrossido di calcio (Poggi et al 2016;Domingues et al 2013;Baglioni et al 2013): la gelatina è ben nota come sistema tamponante, garantendo l'omeostasi sia dei metalli sia del pH, proteggendo le fibre dagli agenti esterni e permettendo al contempo il rilascio dei dannosi composti organici volatili.…”

Sustainability in art conservation: a novel bio-based organogel for the cleaning of water sensitive works of art

“…In chemical gels the polymeric chains form a strong 3D network cross linked by covalent bonds, that prevents the release of gel residues and is capable to retain the cleaning agent into the network more strongly compared to physical gels. Among this class of gels, acrylamide based hydrogels [24], hydroxyethyl methacrylate polymer semi-interpenetrated with poly-vinyl pyrrolidone chains [25,26], poly vinyl alcohol based gels [27,28] and polymethyl metacrylate organogels [29] were developed. Chemical gels were recently proposed for the cleaning of water-sensitive surfaces thanks to their high retentive capability.…”

“…Chemical gels were recently proposed for the cleaning of water-sensitive surfaces thanks to their high retentive capability. Cross-linked polyhydroxyethyl methacrylate and polyvinylpyrrolidone were employed for the removal of hydrophilic soiling material applied on acrylic/vinylic layers, showing an high retentive capability of the cleaning agent and a wide versatility as a fluid container [25,26]. Polyvinyl alcohol based hydrogels were for instance employed for the removal of varnishes from tempera paint layer [27,28].…”