New tool for sustainable treatments: agar spray—research and practice

In the last decades, the research in the field of cultural heritage has shifted its attention to the development of green methods, focusing on the use of renewable and biodegradable materials. Within this scenario, Agar has been one of the most innovative materials available to the conservator. However, sometimes its physical characteristics such as rigidity and gelation temperature are not always an advantage in the treatment of artwork. The atomization of hydrocolloid, a procedure presented in 2019 under the name of Agar spray, has enhanced the performance of this extraordinary material. This work aims to explore the new physical and mechanical characteristics imparted to the gel by the new spray procedure, compared to agar gel that forms under normal environmental conditions. Mechanical resistance and film transparency of both soft materials have been characterized, and the speed of water release has been detected on porous material, lateral solvent flow evaluated for confined cleaning. The new residues, potentially left by the gel after the spray application, were analyzed comparing them with the residues of the gel, which gels at room temperature. The dry Agar films were studied in terms of hydrophobicity of the dry film, agar towards water and water vapor permeability. The data that emerged from the study confirm the new features imparted to the gel by the new procedure, suggesting new measures to be taken to optimize its application.