In this project, you will develop a non-invasive imaging system for the characterisation of layered structures in combination with neutron scattering techniques at the ISIS Neutron and Muon Source. In collaboration with the National Gallery, London and Tate, you will apply this powerful new imaging system to help solve pressing challenges in painting conservation. Neutron scattering has enabled transformative research in heritage science, including ISIS’s recent contributions to elucidating ancient metallurgy techniques, inks on Egyptian textiles, or how environmental conditions affect painting canvases. Through application of cutting-edge imaging techniques like optical coherence tomography (OCT) and spectral imaging, Nottingham Trent University (NTU) has similarly revolutionised heritage science applications and recently won the Queen’s Anniversary Prize for Advancing Heritage Science. This PhD, jointly offered through ISIS and NTU, is a timely way to combine the complementary strengths of OCT and neutron scattering techniques, for the first time, providing a unique new capability for simultaneous observation of the macroscopic and nanoscopic structure of soft matter. The project will involve research work both at Nottingham Trent University, supervised by Lucas Goehring and Haida Liang, and the ISIS Neutron and Muon Source, supervised by Antonella Scherillo and Najet Mahmoudi, at the Harwell campus in Oxfordshire. Paintings are artistic expression in soft materials. Their component layers of polymers, dispersions and emulsions are well-known to soft matter physics and ideal for small-angle neutron scattering. Although appearing static to a gallery visitor, paintings respond to their environment, changing appearance over decades. Preventive conservation mitigates against damage, while restoration attempts to return art to its original look. Scientifically, you will combine OCT and neutron scattering methods to address two of the most important challenges in the restoration of paintings. Blanching involves irreversible damage to a painting by exposure to moisture, causing the varnish or paint to become cloudy or opaque. The effect results from the growth of nanoscopic pores, which scatter visible light. The appearance and evolution of these pores is suggestive of a phase separation process, working to minimise the interface between a hydrophobic varnish polymer and water that has infiltrated into its initially invisible pores. Solvent invasion: Varnishing a painting brings out the colours and provides a protective layer. However, natural varnish degrades and becomes yellow and hazy with time, requiring replacing. For this, solvent is applied that invades and dissolves the varnish before it is reapplied. Understanding how solvents interact with layered paint-varnish structures is one of the most significant challenges in painting restoration.
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