Exploring Cleaning Methodologies for Plastic Artworks Using Laser and Cold Plasma Techniques

Plastics have become part of modern art collections and their preservation is an active area of research which presents many challenges. Plastics in museum collections can deteriorate with surprising suddenness with consequent material damage (plasticiser loss, deformation, colour and compositional changes). Dust and dirt removal are also important conservation challenges; a 2019 survey at Tate, conducted by UCL identified ingrained dirt on 72 and dust on 66 out of 75 surveyed plastic components. The 2012 EU project POPART which focused on the conservation of plastic artefacts identified that approximately 75% of museum-based collections need cleaning.

The cleaning of plastic artworks encompass risk around the development of scratches, modifying surface morphology, the extraction of low molecular weight materials, cleaning system residues, changes to optical surface properties such as transparency and colour, solvent effects, enhanced oxidation and mechanical damage.

This research proposes to investigate unexplored cleaning methodologies for plastic artworks using laser sources and cold plasma radiation.

This project aims to explore the role of laser and cold plasma as conservation cleaning tools for plastic artworks. The research opens the potential to safely treat a higher range of plastics in artworks and in other heritage objects. The project will improve the understanding of these technologies' capabilities and how they can be implemented into wider conservation strategies. Having a greater understanding of the ability of laser and cold plasma cleaning technologies may offer conservators a future cleaning method, not just for surface dirt but also for the removal of acrylic cements and old adhesives.

This is of relevance both nationally and internationally, for any heritage institution with plastics in their collections. The research activities within the project will constitute a contribution to the development of protocols for laser cleaning and cold plasma applications for different categories of plastics.

All plastics cleaning protocols explored so far require contact, which can be hazardous for valuable artworks and there is a need to advance less invasive cleaning strategies since plastics exhibit poor resistance to abrasion. The key advantages of laser and cold plasma treatments are that they are non-contact, solvent-free methods that allow for great control exhibit strong potential as cleaning methods for a wide range of plastics.

This research project aligns with four EPSRC research areas - light matter and optical phenomena, plasma and lasers, polymer materials and surface science.

This is an interdisciplinary research project. The project benefits from collaboration between UCL Medical Physics and Bioengineering and the UCL Institute for Sustainable Heritage. The supervisory team of Prof Adam Gibson and Dr Katherine Curran bring expertise in material-light interactions and plastics degradation, respectively. Also, the interdisciplinary collaboration involves the CNR-ISPC (Italian National Research Council - Institute of Heritage Science) with Dr Cristiano Riminesi who - as prospective co-supervisor - will give access to laser and plasma devices for this project, also sharing his expertise on the application of these technologies for the cleaning of other types of artworks. Moreover, this research could represent cutting-edge solutions for museums with plastic artworks collections; museum Tate already expressed a strong interest in collaborating on this project, which increases Tate's ongoing and past research relationship (e.g. COMPLEX and NANORESTART projects) with the UCL Institute for Sustainable Heritage.