Analysis of ancient materials and their degradation – Lecture 1 MSE-482 Prof. Dr. Claire Gervais

About my group and fundamental research in ancient materials MSE-482 Prof. Dr. Claire Gervais

MSE-482 – L1 Slide 3 Ancient materials, art and sciences Object Social sciences Humanities Art collectors Archaeologists Art historians Conservators Museum curators Artists

MSE-482 – L1 Slide 4 Ancient materials, art and sciences Conservators Preservation, restoration Conservation scientists Design new analytical and conservation procedures Curators Display, history of object Natural scientists Knowledge, Expertise Material Bring natural sciences closer to ancient materials

MSE-482 – L1 Slide 5 Other fields of natural sciences Ancient materials, art and sciences Conservators Preservation, restoration Curators Display, history of object Material Conservation scientists Design new analytical and conservation procedures Gather and generate fundamental knowledge about physico-chemical processes in ancient materials

MSE-482 – L1 Slide 6 Gather and generate fundamental knowledge on ancient materials Work on models highlight factors responsible for these processes Unknown history Precious, tiny Unknown manufacturing Case-study approach Controled history Plenty of material Controled manufacturing Model approach Ancient materials, art and sciences

MSE-482 – L1 Slide 7 Gather and generate fundamental knowledge on ancient materials Work on models Techniques: Synchrotron and computational modeling Access hardly reachable properties of ancient materials Ancient materials, art and sciences

MSE-482 – L1 Slide 8 Gather and generate fundamental knowledge on ancient materials Work on models Techniques: Synchrotron and computational modeling International and national collaborations Ancient materials, art and sciences Target major challenges and get “best of” knowledge

MSE-482 – L1 Slide 9 Other fields of natural sciences Ancient materials, art and sciences Conservators Preservation, restoration Curators Display, history of object Material Conservation scientists Design new analytical and conservation procedures Gather and generate fundamental knowledge about physico-chemical processes in ancient materials

MSE-482 – L1 Slide 10 Ancient materials, art and sciences Material Broaden your definition of materials sciences/chemistry, “out of the box” thinking Describe a variety of ancient materials and research in the field (paintings, ceramics, photographs, wall painting, etc) Propose an analytical framework to optimize information obtained from a micro-sample (appropriate techniques, measurement scale, heterogeneity, radiation damage) Introduction to imaging and spectroscopic synchrotron techniques (X-ray absorption spectroscopy, absorption tomography)

About this course MSE-482 Prof. Dr. Claire Gervais

MSE-482 – L1 Slide 12 Content 1.Introduction to Materials –Materials: definitions, multidisciplinarity, challenges –The triangle Structure-Property-Function –Materials research: Why, What, How, Where? 2.Introduction to ancient materials –Diversity of ancient materials: paintings, archaological objects, fossils, ivory, ceramics. –What is ancient? The concept of materials historicity and impact on their scientific study –Typical reasearch topics in ancient materials 3.Analyzing ancient materials: key concepts –Heterogeneity in materials: a fuzzy concept with clear consequences. –Too big or not too big? The art of adapting measurement scale to property scale. –Sample preparation: bulk, cross-sections, thin-sections, porous materials. –Example: Embedding techniques for thin sections of brittle paint samples.

MSE-482 – L1 Slide 13 Content 4.Synchrotron techniques for ancient materials –Synchrotron light: generation and specificities –A specific synchrotron technique: X-ray absorption spectroscopy –Example: Chrome yellow pigments in Van Gogh’s sunflowers 5.X-ray tomography techniques: Going to 3D and 4D imaging –Materials through the X-ray beam: attenuation coefficients –Acquiring a 3D image: Acquisition and reconstruction (principles) –Basics of image processing: filtering, segmentation, labelization –Example: Virtual unfolding of ancient manuscripts 6.Physico-chemistry of materials degradation –Reproducing and accelerating natural aging: limits of validity. –In-situ analysis of degradation processes. –Radiation damage: how to evaluate it and minimize it. –Example: Radiation damage of Prussian blue paper artworks

MSE-482 – L1 Slide 14 Content (cont’d) 7.Case-studies of ancient materials and their degradation –Cobalt blue degradation in oil paintings. Application of FTIR and XAS imaging to understand potassium leaching leading to pigment discoloration. –Identification of archaeological ivory and its degradation. Application of tomography techniques to analyze porous materials and distinguish between ivory, bone and enamel non-invasively. –Nanoinvestigation of 19th century daguerreotype photographs. New developments in nano X-ray fluorescence to understand the impact of Au gilding on the mechanical stability of the photograph. –Initial corrosion processes in reinforced concrete monuments. In-situ XAS and XRF imaging to decipher transient chemical species in early corrosion process. –Fossilization and diagenesis processes: Insights from rare earth elements. XAS and UV-vis luminescence techniques to discriminate tissues at microscale in fossils. –Technology of ancient ceramics.

MSE-482 – L1 Slide 15 Exercises For each case-study: –Read publication beforehand –Short summary “W 3 H” to discuss in classroom –Discovery of a material –Emphasis on degradation, technique or concept

MSE-482 – L1 Slide 16 Synchrotron virtual session November 12-16: beamtime at synchrotron SOLEIL – October 30: Case-study on Prussian blue – November 6: Design question and experiment together – November 12: Virtual course from beamline (to be defined) – Post-analysis together

MSE-482 – L1 Slide 17 Exam Oral exam with: – Presentation of a selected publication on ancient materials – 1-2 questions on lectures

Materials: a short introduction MSE-482 Prof. Dr. Claire Gervais

MSE-482 – L1 Slide 19 What is a material?

MSE-482 – L1 Slide 20 What is a material? Latin substantia, which means ’something that stands under or grounds things’ [...] The substances in a given philosophical system are those things which, according to that system, are the foundational or fundamental entities of reality.” [Standford University, Philosophy department] And for natural scientists…?

MSE-482 – L1 Slide 21 Why studying materials? To study structure–properties relationships To design new properties To design new functions or improve performance of materials To understand their formation/origin To understand Earth’s history and origin of life To understand Human’s history and art To mitigate diseases, etc.

MSE-482 – L1 Slide 22 Why studying materials? To study structure–properties relationships To design new properties To design new functions or improve performance of materials To understand their formation/origin To understand Earth’s history and origin of life To understand Human’s history and art To mitigate diseases, etc.

MSE-482 – L1 Slide 23 What are materials for scientists? 1.Basic definition A material is defined by a set of individual components or phases, with specific physical properties and functions. Materials are studied by chemists, physicists, geologists, engineers, archaeologists, conservation scientists... Materials science is an interdisciplinary subject, spanning the physics and chemistry of matter, engineering applications and industrial manufacturing processes. [University of Oxford]

MSE-482 – L1 Slide 24 What are materials for scientists? 2.Subjective definitions Multiple names for materials that emphasize one particular aspect: –Synthetic materials –Natural materials –Biomaterials –Geomaterials –Ancient materials –Nanomaterials –Raw materials –Processed materials... Materials science is an applied science concerned with the relationship between the structure and properties of materials. [American Chemical Society]

MSE-482 – L1 Slide 25 What are materials for scientists? 3.Evolving definitions Current paradigm shift to integrate interactions and interfaces between individual components that give rise to specific properties.

MSE-482 – L1 Slide 26 What are materials for scientists? 4.My personal definition A material is defined by a ground set of components featuring specific properties representative of what the material means or has been designed for. Structure MaterialFunctionProperties Origin

MSE-482 – L1 Slide 27 What are materials for scientists? Properties Cut your steak in a restaurant Induce shear deformation Shape, type of wood, decorations Metal microstructure MaterialEating toolCutting toolKnife’s origin Manufactured iron MaterialityMaterial sciences

MSE-482 – L1 Slide 28 Materials characterization : key concepts Because of its versatile definition, characterizing materials requires to answer properly the following questions: – What? Precisely define which function, property, structure, interface, etc. is studied – Where? Evaluate its scale and deal with spatial, chemical, topological heterogeneities – These are prerequisites to choose appropriate characterization techniques and measurement conditions ( How? ). – The Why should not be overlooked (ethics and subjectivity).

MSE-482 – L1 Slide 29 Materials characterization : What and Where? Battery performance Electrode microstructure Structure of active materials? Ratio components? Free electrolyte surface? Interface electrolyte-additive? What?

MSE-482 – L1 Slide 30 Materials characterization : What and Where? Structures and properties of materials span over various length scales: from local atomic order to long-range order on the meso- and macroscopic scales. Materials science deals with these various scales. Where?

MSE-482 – L1 Slide 31 Materials characterization : What and Where? Where?

MSE-482 – L1 Slide 32 Materials characterization : What and Where? Where?

MSE-482 – L1 Slide 33 Materials characterization : How? How? Battery performance Electrode microstructure Structure of active materials? Ratio components? Free electrolyte surface? Interface electrolyte-additive? X-ray absorption spectroscopy X-ray diffraction techniques…

MSE-482 – L1 Slide 34 Materials characterization : What and Where? Characterizing materials implies to keep in mind: – The scale at which the property is defined – The scale at which the measurement is performed – The scale for which the measurement is significant

MSE-482 – L1 Slide 35 Materials characterization : What and Where? Representativity of the measurement?

MSE-482 – L1 Slide 36 Materials characterization : What and Where? Representativity of the measurement = Statistics!

MSE-482 – L1 Slide 37 Materials characterization : What and Where? The art of materials characterization lies in choosing technique and measurement scale to the property of interest while ensuring enough statistics.

MSE-482 – L1 Slide 38 Take-home lesson Materials are often designed/defined by the interest we have in them: multifunctional, synthetic, biogenic, composite, ancient, natural, raw..... Characterizing materials implicitly means characterizing a particular set of functions / properties / component structures, along with the relationships between these components (interface, distribution). Keep in mind the W 3 H! Heterogeneity is a key concept in materials characterization because it conditions the scale at which obtaining a correct measurement. Heterogeneity requires adequate statistical processing. A correct characterization requires also to adapt the length scale of the measurement to that of the feature of interest.