images: Alamy, ESA, Moderna Museet, NASA, Shutterstock, Pixabay, Wikimedia Commons
CHALLENGES CLEANING CARBON-BASED CONTAMINANTS (CBC)
MOXY aims to shift the paradigm in cleaning treatments by researching and developing a groundbreaking green technology, which will contribute to the resolution of many daunting problems of soiling and deposition of carbon-based contaminants (CBC), a major factor of deterioration and a significant concern to the long-term preservation of all tangible cultural heritage assets. Environmental pollution, untenable transport and handling, vandalism, climate crisis events such as wildfires or museum fires can cause catastrophic soot and smoke damage to tangible CH assets in a heartbeat, and effective and safe cleaning is essential for their integrity and preservation.
Some common CH substrates considered for AO
Inorganic plaster, alabaster, sandstone, marble, limestone, cement, clay, dry media, chalks, metals
Organic: canvas (linen, cotton), paper, wood, bone, leather, wax, plastics (cellulose acetate, cellulose nitrate, PVC, PUR).
Organic/inorganic: pastels, tempera, gouache, watercolours, acrylic and emulsion paint, modern oils.
Artwork types: 3D objects (unsealed plaster, alabaster, clay, wax, alloys, etc.), architectural surfaces (fresco, sandstone, cement, etc.), works on paper (drawings, pastels, watercolours), traditional, modern, contemporary paintings (especially unvarnished, mechanically unstable, matte paint, modern oils, acrylic), crossing-boundaries media,
Fire, smoke, wildfires: volatiles organic carbons VOC, soot, hydrocarbons, elemental and organic carbon compounds, brominated flame retardants.
Handling and transport: embedded rubber, plastics, packing, handling marks, rubber scuff-marks, surfactants, organic deposits from packing, labels.
Environmental pollutants: dust, combustion products, cigarette smoking deposits, clothing fibres, VOC, soot.
Defacement and vandalism: adhesives, foods, lipstick, spray paint, ball-pen, markers, other organic materials.
Biological: bacteria, fungi and metabolites, biological fluids, pollen, hair, sloughed-off skin cells, dust mites
Restoration materials: organic binders, natural and synthetic adhesives, resins, waxes, oils, gums, rubber.
Some typical Carbon-based-Contaminants CBC
While there are numerous CBCs and the list of art and CH materials is unlimited, MOXY aims to develop a green AO technology first for extremely sensitive, mechanically unstable, and porous CH materials, which constitute numerous works of art and present formidable challenges to CH professionals, and often cannot be cleaned with available methodologies, techniques and materials without causing unacceptable damage to the irreplaceable underlying substrate, summarised in table below.
Benefits of application of AO cleaning for problematic porous and fragile cultural heritage materials
1. Highly effective contact-free removal of numerous CBC in a green process. AO cleaning does not require any hazardous substances, leaves no residues or waste, nor does it produce any harmful byproducts, making it safe and friendly for end-users, environmentally responsible, and ultimately a sustainable example of green innovation in conservation.
2. The effluent, non-contact delivery of AO provides novel technology to treat vulnerable and difficult-to-access surface areas of CH materials and objects, porous, mechanically unstable materials, planar and complex 3-D micro/macro structures, that cannot safely be cleaned with prevailing methods involving mechanical action, water or solvents, swabs etc.
3. In contrast to prevailing methods, AO ablation of CBC occurs at the very top of the surface at the atomic scale, which enables safe removal of numerous CBCs, without unwanted effects on the CH substrate or diffusion into the bulk.
4. Fire and soot soiling can result in irrecoverable cultural loss due to the effects of corrosive acidic pyrolysis byproducts that irreversibly affect the paint surface if left to dwell more than a few weeks. Implementation of green AO cleaning technology would result in emergency response preparedness that could make safe cleaning of cultural heritage objects damaged by soot possible within the compressed response time, and in a green way.
5. AO contact-free action is localised and controllable with variable intensity and size, with a soft-edged active spot of variable diameter that allows the same tool to be used for small or large-scale areas, and incremental cleaning process. Propelled AO effluent is highly effective for reaching CH surfaces with micro/macro irregular and undercut topographies, especially in the case of removal of contaminants that were deposited through airborne means such as environmental pollution, fire and smoke, or propelled means such as aerosol paint spray in vandalism acts.
6. AO technology and MOXY system design provides immediate visual control and feedback. AO cleaning action is limited to the surface that does not result in the penetration of soiling or cleaning byproducts into porous substrate and can be continuously monitored by the conservator directly, or aided with a multispectral imaging. MOXY AO sensor concept would offer precision, yet affordable and simple to use AO measurement tool for CH professionals.