1
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Gao H, Li H, Zhou X, Wei J, Qu X, Long T. Effect of low molecular weight organic acids on the lead and chromium release from widely-used lead chromate pigments under sunlight irradiation. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 337:122553. [PMID: 37716691 DOI: 10.1016/j.envpol.2023.122553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 09/07/2023] [Accepted: 09/12/2023] [Indexed: 09/18/2023]
Abstract
Lead chromate pigments are commonly used yellow inorganic pigments. They can pose environmental risks as they contain toxic heavy metals lead and chromium. Low molecular weight organic acids (LMWOAs), as widespread dissolved organic matter (DOM), affect the lead and chromium release from the pigment in water. In this work, the role of LMWOAs in the photodissolution of commercial lead chromate pigment was investigated. The pigment underwent significant photodissolution under simulated sunlight exposure with LMWOAs, and subsequently released Cr(III) and Pb(II). The photodissolution process is caused by the reduction of Cr(VI) by photogenerated electrons of the lead chromate pigment. The LMWOAs promoted photodissolution of the pigment by improving the electron-hole separation. The formation of Cr(III)-contained compounds leads to a slower release of chromium than lead. The photodissolution kinetics increase with decreasing pH and increasing LMWOAs concentration. The photodissolution of lead chromate pigment was basically positively related to the total number of hydroxyl and carboxyl groups in LMWOAs. The LMWOAs with stronger affinity to lead chromate pigment, lower adiabatic ionization potential (AIP) and higher energy of the highest occupied molecular orbital (EHOMO) are favorable to Cr(VI) reduction by photogenerated electrons and pigment photodissolution. 2.39% of chromium and 10.34% of lead released from the lead chromate pigment in natural conditions during a 6-h sunlight exposure. This study revealed the photodissolution mechanism of lead chromate pigment mediated by LMWOAs with different molecular structures, which helps understand the environmental photochemical behavior of the pigment. The present results emphasize the important role of DOM in the heavy metals release from commercial inorganic pigments.
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Affiliation(s)
- Han Gao
- State Environmental Protection Key Laboratory of Soil Environmental Management and Pollution Control, Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment of China, Nanjing, Jiangsu, 210042, China; State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, 210023, China
| | - Huixin Li
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, 210023, China
| | - Xinwei Zhou
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang, Jiangsu, 212100, China
| | - Jing Wei
- State Environmental Protection Key Laboratory of Soil Environmental Management and Pollution Control, Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment of China, Nanjing, Jiangsu, 210042, China
| | - Xiaolei Qu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment, Nanjing University, Nanjing, Jiangsu, 210023, China
| | - Tao Long
- State Environmental Protection Key Laboratory of Soil Environmental Management and Pollution Control, Nanjing Institute of Environmental Sciences, Ministry of Ecology and Environment of China, Nanjing, Jiangsu, 210042, China.
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2
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Groeneveld I, Jaspars A, Akca IB, Somsen GW, Ariese F, van Bommel MR. Use of liquid-core waveguides as photochemical reactors and/or for chemical analysis – An overview. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY 2023. [DOI: 10.1016/j.jpap.2023.100168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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3
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Liu H, Xu C, Xia Q, Ying Y, Li Q, Zhao X, Zhang Y, Yang S. Tailorable and Angle-Independent Colors from Synthetic Brochosomes. ACS NANO 2023; 17:2257-2265. [PMID: 36661565 DOI: 10.1021/acsnano.2c08598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Although various artificial dyes and pigments have been invented, certain application fields need structural colors because they can last for centuries even under harsh conditions. Here, we report that the antireflective Ag brochosomes (soccer-ball-like microscale granules covered by nanobowls) become colorful when the nanobowls on the Ag brochosomes are filled by polystyrene (PS) nanospheres. The color originates from the enhanced electromagnetic resonances of the PS nanospheres by the surrounding metallic nanobowls, suggested by both the experimental and the simulation results. The color is determined by the size of the PS nanospheres. We can tailor the color simply by reducing the diameter of the PS nanospheres via the plasma etching treatment. The color intensity of the Ag brochosomes filled with PS nanospheres shows weak dependence on the observing angles, benefiting from their spherical shape. Plasma etching treatment of the Ag brochosomes filled with PS nanospheres through different masks can design various structural color patterns. The simple fabrication process and the easy processability make the Ag brochosomes filled with PS nanospheres have promising applications in the structural color fields.
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Affiliation(s)
- Hong Liu
- Department of Medical Oncology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
- Institute for Composites Science Innovation, School of Materials Science and Engineering, Zhejiang University, 310027 Hangzhou, China
| | - Chao Xu
- Institute for Composites Science Innovation, School of Materials Science and Engineering, Zhejiang University, 310027 Hangzhou, China
| | - Qundong Xia
- Institute for Composites Science Innovation, School of Materials Science and Engineering, Zhejiang University, 310027 Hangzhou, China
| | - Yunbin Ying
- School of Optical Science and Engineering, Zhejiang University, 310027 Hangzhou, China
| | - Qiang Li
- School of Optical Science and Engineering, Zhejiang University, 310027 Hangzhou, China
| | - Xiaoyu Zhao
- School of Material and Environmental Engineering, Hangzhou Dianzi University, 310018 Hangzhou, China
| | - Yongjun Zhang
- School of Material and Environmental Engineering, Hangzhou Dianzi University, 310018 Hangzhou, China
| | - Shikuan Yang
- Department of Medical Oncology, The First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou 310003, China
- Institute for Composites Science Innovation, School of Materials Science and Engineering, Zhejiang University, 310027 Hangzhou, China
- State Key Laboratory of Fluid Power and Mechatronic Systems, Zhejiang University, Hangzhou 310027, China
- Baotou Research Institute of Rare Earths, Baotou 014030, China
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4
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Karl U. „Gemälde verwelken wie Blumen“. CHEM UNSERER ZEIT 2022. [DOI: 10.1002/ciuz.202100021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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5
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De Keyser N, Broers F, Vanmeert F, De Meyer S, Gabrieli F, Hermens E, Van der Snickt G, Janssens K, Keune K. Reviving degraded colors of yellow flowers in 17th century still life paintings with macro- and microscale chemical imaging. SCIENCE ADVANCES 2022; 8:eabn6344. [PMID: 35675402 PMCID: PMC9176749 DOI: 10.1126/sciadv.abn6344] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 04/22/2022] [Indexed: 06/15/2023]
Abstract
Over time, artist pigments are prone to degradation, which can decrease the readability of the artwork or notably change the artist's intention. In this article, the visual implication of secondary degradation products in a degraded yellow rose in a still life painting by A. Mignon is discussed as a case study. A multimodal combination of chemical and optical imaging techniques, including noninvasive macroscopic x-ray powder diffraction (MA-XRPD) and macroscopic x-ray fluorescence imaging, allowed us to gain a 3D understanding of the transformation of the original intended appearance of the rose into its current degraded state. MA-XRPD enabled us to precisely correlate in situ formed products with what is optically visible on the surface and demonstrated that the precipitated lead arsenates and arsenolite from the yellow pigment orpiment and the light-induced fading of an organic yellow lake irreversibly changed the artist's intentional light-shadow modeling.
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Affiliation(s)
- Nouchka De Keyser
- University of Antwerp, Department of Physics, AXIS Research Group, Groenenborgerlaan 171, B-2010 Antwerp, Belgium
- Rijksmuseum, Museumstraat 1, Amsterdam, 1070 DN, Netherlands
- University of Antwerp, Faculty of Design Sciences, ARCHES Research Group, Mutsaardstraat 31, B-2000 Antwerp, Belgium
- University of Amsterdam, van ‘t Hoff Institute for Molecular Sciences, 1090GD Amsterdam, Netherlands
| | - Fréderique Broers
- University of Antwerp, Department of Physics, AXIS Research Group, Groenenborgerlaan 171, B-2010 Antwerp, Belgium
- Rijksmuseum, Museumstraat 1, Amsterdam, 1070 DN, Netherlands
- University of Amsterdam, van ‘t Hoff Institute for Molecular Sciences, 1090GD Amsterdam, Netherlands
- Utrecht University, Inorganic Chemistry and Catalysis, Universiteitsweg 99, 3584 CG Utrecht, Netherlands
| | - Frederik Vanmeert
- University of Antwerp, Department of Physics, AXIS Research Group, Groenenborgerlaan 171, B-2010 Antwerp, Belgium
- Royal Institute for Cultural Heritage, Laboratories, Jubelpark 1, 1000 Brussels, Belgium
| | - Steven De Meyer
- University of Antwerp, Department of Physics, AXIS Research Group, Groenenborgerlaan 171, B-2010 Antwerp, Belgium
| | | | - Erma Hermens
- Rijksmuseum, Museumstraat 1, Amsterdam, 1070 DN, Netherlands
- University of Amsterdam, Art History Department, Turfdraagsterpad 15-17, 1012XT Amsterdam, Netherlands
| | - Geert Van der Snickt
- University of Antwerp, Department of Physics, AXIS Research Group, Groenenborgerlaan 171, B-2010 Antwerp, Belgium
- University of Antwerp, Faculty of Design Sciences, ARCHES Research Group, Mutsaardstraat 31, B-2000 Antwerp, Belgium
| | - Koen Janssens
- University of Antwerp, Department of Physics, AXIS Research Group, Groenenborgerlaan 171, B-2010 Antwerp, Belgium
- Rijksmuseum, Museumstraat 1, Amsterdam, 1070 DN, Netherlands
- University of Antwerp, Faculty of Design Sciences, ARCHES Research Group, Mutsaardstraat 31, B-2000 Antwerp, Belgium
| | - Katrien Keune
- Rijksmuseum, Museumstraat 1, Amsterdam, 1070 DN, Netherlands
- University of Amsterdam, van ‘t Hoff Institute for Molecular Sciences, 1090GD Amsterdam, Netherlands
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Ghirardello M, Gonzalez V, Monico L, Nevin A, MacLennan D, Patterson CS, Burghammer M, Réfrégiers M, Comelli D, Cotte M. Application of Synchrotron Radiation-Based Micro-Analysis on Cadmium Yellows in Pablo Picasso's Femme. MICROSCOPY AND MICROANALYSIS : THE OFFICIAL JOURNAL OF MICROSCOPY SOCIETY OF AMERICA, MICROBEAM ANALYSIS SOCIETY, MICROSCOPICAL SOCIETY OF CANADA 2022; 28:1-10. [PMID: 35644640 DOI: 10.1017/s1431927622000873] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The cultural heritage community is increasingly exploring synchrotron radiation (SR) based techniques for the study of art and archaeological objects. When considering heterogeneous and complex micro-samples, such as those from paintings, the combination of different SR X-ray techniques is often exploited to overcome the intrinsic limitations and sensitivity of the single technique. Less frequently, SR X-ray analyses are combined with SR micro-photoluminescence or micro-Fourier Transform Infrared spectroscopy, which provide complementary information on the molecular composition, offering a unique integrated analysis approach. Although the spatial correlation between the maps obtained with different techniques is not straightforward due to the different volumes probed by each method, the combination of the information provides a greater understanding and insight into the paint chemistry. In this work, we discuss the advantages and disadvantages of the combination of X-ray techniques and SR-based photoluminescence through the study of two paint micro-samples taken from Pablo Picasso's Femme (1907). The painting contains two cadmium yellow paints (based on CdS): one relatively intact and one visibly degraded. SR micro-analyses demonstrated that the two Cd-yellow paints differ in terms of structure, chemical composition, and photoluminescence properties. In particular, on the basis of the combination of different SR measurements, we hypothesize that the degraded yellow is based on nanocrystalline CdS with high presence of Cd(OH)Cl. These two characteristics have enhanced the reactivity of the paint and strongly influenced its stability.
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Affiliation(s)
- Marta Ghirardello
- Physics Department, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Victor Gonzalez
- Université Paris-Saclay, ENS Paris-Saclay, CNRS, PPSM, 91190 Gif-sur-Yvette, France
| | | | - Austin Nevin
- IFN-CNR, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
- Courtauld Institute of Art, Somerset House, Strand, London WC2R ORN, UK
| | - Douglas MacLennan
- Science Department, Getty Conservation Institute, 1200 Getty Center Drive, Los Angeles, CA 90049, USA
| | | | | | - Matthieu Réfrégiers
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, Gif-sur-Yvette, France
- CBM UPR4301, Rue Charles Sadron, Orléans, France
| | - Daniela Comelli
- Physics Department, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy
| | - Marine Cotte
- ESRF, 71 Avenue des Martyrs, 38000 Grenoble, France
- LAMS, CNRS UMR 8220, Sorbonne Université, UPMC Univ. Paris 06, Place Jussieu 4, F-75005 Paris, France
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7
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Modelling the Interaction between Carboxylic Acids and Zinc Oxide: Insight into Degradation of ZnO Pigments. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27113362. [PMID: 35684300 PMCID: PMC9181975 DOI: 10.3390/molecules27113362] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 05/11/2022] [Accepted: 05/17/2022] [Indexed: 11/28/2022]
Abstract
Computational modelling applied to cultural heritage can assist the characterization of painting materials and help to understand their intrinsic and external degradation processes. The degradation of the widely employed zinc oxide (ZnO)—a white pigment mostly used in oil paints—leads to the formation of metal soaps, complexes of Zn ions and long-chain fatty acids coming from the degradation of the oil binder. Being a serious problem affecting the appearance and the structural integrity of many oil paintings, it is relevant to characterize the structure of these complexes and to understand the reaction pathways associated with this degradation process. Density functional theory (DFT) calculations were performed to investigate the adsorption of the acetate and acetic acid on relatively large ZnO clusters and the formation of Zn–acetate complexes. Carboxylic acids with longer alkyl chains were then investigated as more realistic models of the fatty acids present in the oil medium. In addition, DFT calculations using a periodic ZnO slab were performed in order to compare the obtained results at different levels of theory. Optimization calculations as well as the formation energies of the ZnO@carboxylate coupled systems and the thermodynamics leading to possible degradation products were computed. Our results highlight the potential for DFT calculations to provide a better understanding of oil paint degradation, with the aim of contributing to the development of strengthening and conservation strategies of paintings.
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8
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Elert K, Pérez Mendoza M, Cardell C. Direct evidence for metallic mercury causing photo-induced darkening of red cinnabar tempera paints. Commun Chem 2021; 4:174. [PMID: 36697873 PMCID: PMC9814095 DOI: 10.1038/s42004-021-00610-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2021] [Accepted: 11/19/2021] [Indexed: 01/28/2023] Open
Abstract
Photo-induced darkening of red cinnabar (HgS) has attracted the interest of many researchers as it drastically impacts the visual perception of artworks. Darkening has commonly been related to metallic mercury (Hg0) formation in the presence of chlorides. Based on the study of UV-aged cinnabar pigment and tempera paint we propose an alternative pathway for the blackening reaction of cinnabar, considering its semiconductor properties and pigment-binder interactions. We demonstrate that darkening is caused by the oxidation of cinnabar to mercury sulfates and subsequent reduction to Hg0 via photo-induced electron transfer without the involvement of chlorides, and provide direct evidence for the presence of Hg0 on UV-aged tempera paint. Photooxidation also affects the organic binder, causing a competing depletion of photo-generated holes and consequently limiting but not impeding mercury sulfate formation and subsequent reduction to Hg0. In addition, organics provide active sites for Hg0 sorption, which is ultimately responsible for the darkening of cinnabar-based paint.
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Affiliation(s)
- Kerstin Elert
- Department of Mineralogy and Petrology, University of Granada, Avenida de Fuentenueva S/N, 18071, Granada, Spain.
| | - Manuel Pérez Mendoza
- grid.4489.10000000121678994Department of Inorganic Chemistry, University of Granada, Avenida de Fuentenueva S/N, 18071 Granada, Spain
| | - Carolina Cardell
- grid.4489.10000000121678994Department of Mineralogy and Petrology, University of Granada, Avenida de Fuentenueva S/N, 18071 Granada, Spain
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9
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Reviving Alexander Calder’s Man-Eater with Pennants: A Technical Examination of the Original Paint Palette. HERITAGE 2021. [DOI: 10.3390/heritage4030109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Man-Eater with Pennants, a rarely exhibited sculpture in Alexander Calder’s oeuvre, was commissioned by The Museum of Modern Art (MoMA) and installed in 1945. To exhibit the large standing mobile in Alexander Calder: Modern from the Start (2021), the derelict sculpture had to be remediated; this initiated a collaborative investigation with conservation scientists, conservators, curators, and the Calder Foundation into the original paint colors hidden beneath layers of repaint. XRF analysis was carried out to elucidate the paints’ composition, followed by sampling for analysis to assess the paint stratigraphy and binders. Scrapings were analyzed by µ-FTIR and Raman spectroscopies; cross sections were examined with optical microscopy and analyzed with SEM-EDS. Analysis differentiated between the original paints, which contain Prussian blue, parachlor red, chrome yellow, and the many layers of overpaint, which contain titanium white, molybdate orange, a variety of β-Naphthol reds, red lead, and ultramarine. A model for Man-Eater, Mobile with 14 Flags, is also part of the museum’s collection, and was first considered as a point of reference for the original colors. Similar analysis, however, indicates that the maquette was painted after the Man-Eater was first installed, therefore is not representative of the original colors. In addition to investigating an early primary palette for Calder’s outdoor sculptures, this study helped develop the plan for the restoration of the original color scheme of Man-Eater.
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Micheluz A, Angelin EM, Lopes JA, Melo MJ, Pamplona M. Discoloration of Historical Plastic Objects: New Insight into the Degradation of β-Naphthol Pigment Lakes. Polymers (Basel) 2021; 13:2278. [PMID: 34301037 PMCID: PMC8309268 DOI: 10.3390/polym13142278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Revised: 06/30/2021] [Accepted: 07/08/2021] [Indexed: 01/12/2023] Open
Abstract
Light is a determining factor in the discoloration of plastics, and photodegradation processes can affect the molecular structures of both the polymer and colorants. Limited studies focused on the discoloration of heritage plastics in conservation science. This work investigated the discoloration of red historical polyethylene (PE) objects colored with PR 48:2 and PR 53:1. High-density and low-density PE reference polymers, neat pigment powders, and historical samples were assessed before and after accelerated photoaging. The applied methodology provided insight into the individual light-susceptibility of polyethylenes, organic pigment lakes, and their combined effect in the photoaging of historical plastic formulations. After light exposure, both PE references and historical samples yellowed, PR53:1 faded, and PR 48:2 darkened; however, both organic pigments faded severely in the historical samples. This highlights the role played by the plastic binder likely facilitating the pigment photofading. Fourier transform infrared spectroscopy and mass spectrometry techniques-EGA-MS, PY-GC/MS, and TD-GC/MS-were successfully employed for characterizing the plastic formulations and degradation. The identification of phthalic compounds in both aged β-naphthol powders opens new venues for studies on their degradation. This work's approach and analytical methods in studying the discoloration of historical plastics are novel, proving their efficacy, reliability, and potentiality.
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Affiliation(s)
- Anna Micheluz
- Conservation Science Department, Deutsches Museum, Museumsinsel 1, 80538 Munich, Germany;
| | - Eva Mariasole Angelin
- Department of Conservation and Restoration and LAQV-REQUIMTE, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Lisbon, Portugal;
| | - João Almeida Lopes
- iMed.ULisboa-Research Institute for Medicines, Faculty of Pharmacy, University of Lisbon, Av. Prof. Gama Pinto, 1649-003 Lisbon, Portugal;
| | - Maria João Melo
- Department of Conservation and Restoration and LAQV-REQUIMTE, NOVA School of Science and Technology, NOVA University Lisbon, 2829-516 Lisbon, Portugal;
| | - Marisa Pamplona
- Conservation Science Department, Deutsches Museum, Museumsinsel 1, 80538 Munich, Germany;
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La Nasa J, Doherty B, Rosi F, Braccini C, Broers FTH, Degano I, Matinero JM, Miliani C, Modugno F, Sabatini F, Sandu ICA, Cartechini L. An integrated analytical study of crayons from the original art materials collection of the MUNCH museum in Oslo. Sci Rep 2021; 11:7152. [PMID: 33785789 PMCID: PMC8010065 DOI: 10.1038/s41598-021-86031-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/05/2021] [Indexed: 11/08/2022] Open
Abstract
Among the artists' materials of the nineteenth century, pastel crayons merit scientific interest since their early commercial formulations are mostly unknown and, until now, have been considerably less studied with respect to other contemporary painting materials. In this framework, research herein reports the results of a comprehensive multi-analytical study of 44 pastel crayons of two recognized brands (LeFranc and Dr. F. Schoenfeld) from the Munch museum collection of original materials belonging to Edvard Munch. The integrated use of complementary spectroscopic and hyphenated mass-spectrometry techniques allowed the compositional profiles of the crayons to be traced providing the identification of the inorganic and organic pigments, the fillers/extenders and the binders. All crayons resulted to be oil- based and the binder was identified to be a mixture of a drying oil (safflower or linseed oil), palm oil or Japan wax and beeswax. Among others, pigments such as ultramarine, chrome yellows, Prussian blue, manganese violet, viridian and madder lake have been identified. A significant alignment in formulations of the brands was observed with the only exception of the greens which showed distinctive pigment and filler compositions. The analytical information provided for these commercial artists' materials will be of great interest for academia, museum and other institutions hosting art collections dating from the same period and it will be used by the Munch museum to draw proper conservation strategies of its own artwork collections.
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Affiliation(s)
- Jacopo La Nasa
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124, Pisa, Italy
| | - Brenda Doherty
- Istituto CNR di Scienze e Tecnologie Chimiche "G.Natta" CNR-SCITEC, Via Elce di Sotto 8, 01628, Perugia, Italy.
| | - Francesca Rosi
- Istituto CNR di Scienze e Tecnologie Chimiche "G.Natta" CNR-SCITEC, Via Elce di Sotto 8, 01628, Perugia, Italy.
| | - Chiara Braccini
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124, Pisa, Italy
| | - Frederique T H Broers
- Istituto CNR di Scienze e Tecnologie Chimiche "G.Natta" CNR-SCITEC, Via Elce di Sotto 8, 01628, Perugia, Italy
| | - Ilaria Degano
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124, Pisa, Italy
| | - Jordi Moles Matinero
- Istituto CNR di Scienze e Tecnologie Chimiche "G.Natta" CNR-SCITEC, Via Elce di Sotto 8, 01628, Perugia, Italy
| | - Costanza Miliani
- Istituto CNR per le Scienze del Patrimonio Culturale (CNR-ISPC), Via Cardinale Guglielmo Sanfelice 8, 80134, Napoli, Italy
| | - Francesca Modugno
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124, Pisa, Italy
| | - Francesca Sabatini
- Department of Chemistry and Industrial Chemistry, University of Pisa, Via G. Moruzzi 13, 56124, Pisa, Italy
| | - Irina Crina Anca Sandu
- Department of Collection Care and Management, MUNCH, Edvard Munchs Plass 1, Sørenga, Postboks 3304, 0194, Oslo, Norway
| | - Laura Cartechini
- Istituto CNR di Scienze e Tecnologie Chimiche "G.Natta" CNR-SCITEC, Via Elce di Sotto 8, 01628, Perugia, Italy
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Kang J, Gwon YR, Cho SK. Photoelectrochemical water oxidation on PbCrO4 thin film photoanode fabricated via Pechini method: Various solution-processes for PbCrO4 film synthesis. J Electroanal Chem (Lausanne) 2020. [DOI: 10.1016/j.jelechem.2020.114601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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13
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Angelin EM, Ghirardello M, Babo S, Picollo M, Chelazzi L, Melo MJ, Nevin A, Valentini G, Comelli D. The multi-analytical in situ analysis of cadmium-based pigments in plastics. Microchem J 2020. [DOI: 10.1016/j.microc.2020.105004] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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Monico L, Cartechini L, Rosi F, Chieli A, Grazia C, De Meyer S, Nuyts G, Vanmeert F, Janssens K, Cotte M, De Nolf W, Falkenberg G, Sandu ICA, Tveit ES, Mass J, de Freitas RP, Romani A, Miliani C. Probing the chemistry of CdS paints in The Scream by in situ noninvasive spectroscopies and synchrotron radiation x-ray techniques. SCIENCE ADVANCES 2020; 6:eaay3514. [PMID: 32440540 PMCID: PMC7228759 DOI: 10.1126/sciadv.aay3514] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Accepted: 03/06/2020] [Indexed: 05/15/2023]
Abstract
The degradation of cadmium sulfide (CdS)-based oil paints is a phenomenon potentially threatening the iconic painting The Scream (ca. 1910) by Edvard Munch (Munch Museum, Oslo) that is still poorly understood. Here, we provide evidence for the presence of cadmium sulfate and sulfites as alteration products of the original CdS-based paint and explore the external circumstances and internal factors causing this transformation. Macroscale in situ noninvasive spectroscopy studies of the painting in combination with synchrotron-radiation x-ray microspectroscopy investigations of a microsample and artificially aged mock-ups show that moisture and mobile chlorine compounds are key factors for promoting the oxidation of CdS, while light (photodegradation) plays a less important role. Furthermore, under exposure to humidity, parallel/secondary reactions involving dissolution, migration through the paint, and recrystallization of water-soluble phases of the paint are associated with the formation of cadmium sulfates.
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Affiliation(s)
- Letizia Monico
- CNR-SCITEC, via Elce di Sotto 8, 06123 Perugia, Italy
- SMAArt Centre and Department of Chemistry, Biology, and Biotechnology, University of Perugia, via Elce di Sotto 8, 06123 Perugia, Italy
- AXES Research Group, NANOlab Centre of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
- Corresponding author. (L.M.); (C.M.)
| | - Laura Cartechini
- CNR-SCITEC, via Elce di Sotto 8, 06123 Perugia, Italy
- SMAArt Centre and Department of Chemistry, Biology, and Biotechnology, University of Perugia, via Elce di Sotto 8, 06123 Perugia, Italy
| | - Francesca Rosi
- CNR-SCITEC, via Elce di Sotto 8, 06123 Perugia, Italy
- SMAArt Centre and Department of Chemistry, Biology, and Biotechnology, University of Perugia, via Elce di Sotto 8, 06123 Perugia, Italy
| | - Annalisa Chieli
- CNR-SCITEC, via Elce di Sotto 8, 06123 Perugia, Italy
- SMAArt Centre and Department of Chemistry, Biology, and Biotechnology, University of Perugia, via Elce di Sotto 8, 06123 Perugia, Italy
| | - Chiara Grazia
- CNR-SCITEC, via Elce di Sotto 8, 06123 Perugia, Italy
- SMAArt Centre and Department of Chemistry, Biology, and Biotechnology, University of Perugia, via Elce di Sotto 8, 06123 Perugia, Italy
| | - Steven De Meyer
- AXES Research Group, NANOlab Centre of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Gert Nuyts
- AXES Research Group, NANOlab Centre of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Frederik Vanmeert
- AXES Research Group, NANOlab Centre of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Koen Janssens
- AXES Research Group, NANOlab Centre of Excellence, University of Antwerp, Groenenborgerlaan 171, 2020 Antwerp, Belgium
- Rijksmuseum, Conservation & Restoration—Scientific Research, Hobbemastraat 22, 1071 ZC Amsterdam, Netherlands
| | - Marine Cotte
- ESRF, 71 Avenue des Martyrs, 38000 Grenoble, France
- LAMS, CNRS UMR 8220, Sorbonne Université, UPMC Univ. Paris 06, 4 place Jussieu, 75005 Paris, France
| | - Wout De Nolf
- ESRF, 71 Avenue des Martyrs, 38000 Grenoble, France
| | | | | | | | - Jennifer Mass
- Bard Graduate Center, 86th St., New York, NY 10024, USA
- Scientific Analysis of Fine Art LLC, 843 Old State Rd., Berwyn, PA 19312, USA
| | - Renato Pereira de Freitas
- CNR-SCITEC, via Elce di Sotto 8, 06123 Perugia, Italy
- LISComp Laboratory, Federal Institute of Rio de Janeiro, Paracambi, RJ 26600000, Brazil
| | - Aldo Romani
- CNR-SCITEC, via Elce di Sotto 8, 06123 Perugia, Italy
- SMAArt Centre and Department of Chemistry, Biology, and Biotechnology, University of Perugia, via Elce di Sotto 8, 06123 Perugia, Italy
| | - Costanza Miliani
- CNR-SCITEC, via Elce di Sotto 8, 06123 Perugia, Italy
- SMAArt Centre and Department of Chemistry, Biology, and Biotechnology, University of Perugia, via Elce di Sotto 8, 06123 Perugia, Italy
- CNR-ISPC, via Cardinale Guglielmo Sanfelice 8, 80134 Napoli, Italy
- Corresponding author. (L.M.); (C.M.)
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15
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Nabais P, Oliveira J, Pina F, Teixeira N, de Freitas V, Brás NF, Clemente A, Rangel M, Silva AMS, Melo MJ. A 1000-year-old mystery solved: Unlocking the molecular structure for the medieval blue from Chrozophora tinctoria, also known as folium. SCIENCE ADVANCES 2020; 6:eaaz7772. [PMID: 32426456 PMCID: PMC7164948 DOI: 10.1126/sciadv.aaz7772] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Accepted: 01/22/2020] [Indexed: 05/25/2023]
Abstract
The molecular structure of the medieval watercolor known as folium has finally been solved in the 21st century. The interdisciplinary approach taken was the key to producing extracts that had been prepared following medieval instructions, and shows the blue/purple chromophore as the major dye in Chrozophora tinctoria fruits (shell). A multi-analytical characterization of its structure was made using HPLC-DAD-MS, GC-MS, NMR (1H, 13C, COSY, HSQC, HMBC, INADEQUATE), and computational studies. The results demonstrate that the blue compound corresponds to 6'-hydroxy-4,4'-dimethoxy-1,1'-dimethyl-5'-{[3,4,5-trihydroxy-6-(hydroxymethyl)tetrahydro-2H-pyran-2-yl]oxy}-[3,3'-bipyridine]-2,2',5,6(1H,1'H)-tetraone, a hermidin derivative, which we named chrozophoridin. Experimental data and computational modeling studies show that this mono-glycosylated dimer is represented by two stable isomers (atropisomers). This is an indispensable piece of knowledge for the characterization of this medieval dye in works of art such as medieval manuscript illuminations and for testing its stability and contributes to the preservation of our cultural heritage.
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Affiliation(s)
- P. Nabais
- REQUIMTE–Laboratório Associado para a Química Verde, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Campus Caparica, 2829-516 Monte de Caparica, Portugal
| | - J. Oliveira
- REQUIMTE–Laboratório Associado para a Química Verde, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - F. Pina
- REQUIMTE–Laboratório Associado para a Química Verde, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Campus Caparica, 2829-516 Monte de Caparica, Portugal
| | - N. Teixeira
- REQUIMTE–Laboratório Associado para a Química Verde, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - V. de Freitas
- REQUIMTE–Laboratório Associado para a Química Verde, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - N. F. Brás
- REQUIMTE–UCIBIO, Faculdade de Ciências, Universidade do Porto, Rua do Campo Alegre, s/n, 4169-007 Porto, Portugal
| | - A. Clemente
- cE3c–Centre for Ecology, Evolution and Environmental Changes, Faculdade de Ciências, Universidade de Lisboa, Campo Grande, 1749-016 Lisboa, Portugal
| | - M. Rangel
- REQUIMTE–Laboratório Associado para a Química Verde, Instituto de Ciências Biomédicas de Abel Salazar, Universidade do Porto
| | - A. M. S. Silva
- REQUIMTE–Laboratório Associado para a Química Verde, Departamento de Química, and QOPNA, University of Aveiro, 3810-193 Aveiro, Portugal
| | - M. J. Melo
- REQUIMTE–Laboratório Associado para a Química Verde, Faculdade de Ciências e Tecnologia, Universidade NOVA de Lisboa, Campus Caparica, 2829-516 Monte de Caparica, Portugal
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16
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Non-Linear Microscopy: A Well-Established Technique for Biological Applications towards Serving as a Diagnostic Tool for in situ Cultural Heritage Studies. SUSTAINABILITY 2020. [DOI: 10.3390/su12041409] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A range of sophisticated imaging techniques have been developed in recent years that can reveal the surface structure of cultural heritage objects with varying precision. In combination with various spectroscopic methods, they allow the study of the chemical composition of the object; thus, conclusions can be drawn about the origin of the object or its initial components, method, or time of creation, authenticity, mechanisms of degradation, and ways of further conservation. At present, different techniques can be applied to a wide range of cultural heritage objects, such as varnishes, paintings, archaeological objects, binding media, paper-based documents, parchments, marbles, frescoes, as well as various objects made of leather, fabric, stone, ceramics and glass, wood, or metal. One of the main needs in the study of cultural heritage (CH) is the transportability/portability of the research equipment, since many pieces under investigation cannot be moved to the laboratory, either because of their size, inseparability (for example, frescoes on walls, mural paintings in caves), or the threat of damage. In this work, we briefly overview the main optical- and laser-based methods used for the study of cultural heritage objects indicating the scope of their application, and we focus on the applications of non-linear microscopic methods for the investigation of a series of artifacts. We also discuss all the requirements for the construction of a prototype transportable non-linear optical system that will be used as a novel diagnostic tool for in situ studies of CH assets. The availability of such a transportable workstation will significantly improve the study and characterization of various types of CH objects and will constitute an extremely useful diagnostic tool for heritage scientists dealing with a variety of investigations.
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17
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Alter M, Binet L, Touati N, Lubin-Germain N, Le Hô AS, Mirambet F, Gourier D. Photochemical Origin of the Darkening of Copper Acetate and Resinate Pigments in Historical Paintings. Inorg Chem 2019; 58:13115-13128. [PMID: 31524393 DOI: 10.1021/acs.inorgchem.9b02007] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Copper acetate and copper resinate pigments are bimetallic CuII complexes in which metal atoms are bridged by four carboxylate ligands (acetate or abietate). Prepared with lindseed oil as binder, these green pigments were particularly used in easel paintings between the 15th and 17th centuries. Unfortunately, they had the tendency to darken in an irreversible way, explaining why they fell into disuse. The darkening mechanism of films of copper pigments in linseed oil is studied by electron paramagnetic resonance (EPR) and by optical absorption spectroscopy (OAS). EPR and OAS reveal different chemical and photochemical behaviors depending on the type of copper complex and on the binding oil. The effect of light is investigated by illuminating the films at ∼410 nm in the bridging ligand-to-metal charge transfer (LMCT) transition. The photodarkening manifests itself as the appearance of an optical absorption band around 22 000 cm-1 and a decrease of the EPR intensity of bimetallic copper complexes. These effects are explained by the photoinduced substitution of acetate (or abietate) bridging ligands by dioxygen molecules from ambient atmosphere. The resulting peroxo-CuII dimer is characterized by a red shift of the LMCT and an increase of the exchange interaction in the ground state, which is responsible for the decrease of the EPR intensity due to the depletion of the paramagnetic S = 1 state. This mechanism explains the differences in darkening intensity observed with different pigment compositions (resinate versus acetate, raw linseed oil versus boiled linseed oil).
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Affiliation(s)
- Marion Alter
- CNRS, Institut de Recherche de Chimie de Paris (IRCP) , Chimie-ParisTech, PSL University , 75005 Paris , France.,Centre de Recherche et de Restauration des Musées de France (C2RMF) , Palais du Louvre , 75001 Paris , France
| | - Laurent Binet
- CNRS, Institut de Recherche de Chimie de Paris (IRCP) , Chimie-ParisTech, PSL University , 75005 Paris , France.,Centre de Recherche et de Restauration des Musées de France (C2RMF) , Palais du Louvre , 75001 Paris , France
| | - Nadia Touati
- CNRS, Institut de Recherche de Chimie de Paris (IRCP) , Chimie-ParisTech, PSL University , 75005 Paris , France.,Centre de Recherche et de Restauration des Musées de France (C2RMF) , Palais du Louvre , 75001 Paris , France
| | - Nadège Lubin-Germain
- Laboratoire de Chimie Biologique (LCB) , EA4505, Université de Cergy-Pontoise , 95510 Cergy-Pontoise , France
| | - Anne-Solenn Le Hô
- CNRS, Institut de Recherche de Chimie de Paris (IRCP) , Chimie-ParisTech, PSL University , 75005 Paris , France.,Centre de Recherche et de Restauration des Musées de France (C2RMF) , Palais du Louvre , 75001 Paris , France
| | - François Mirambet
- CNRS, Institut de Recherche de Chimie de Paris (IRCP) , Chimie-ParisTech, PSL University , 75005 Paris , France.,Centre de Recherche et de Restauration des Musées de France (C2RMF) , Palais du Louvre , 75001 Paris , France
| | - Didier Gourier
- CNRS, Institut de Recherche de Chimie de Paris (IRCP) , Chimie-ParisTech, PSL University , 75005 Paris , France.,Centre de Recherche et de Restauration des Musées de France (C2RMF) , Palais du Louvre , 75001 Paris , France
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18
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Berenbeim J, Boldissar S, Owens S, Haggmark M, Gate G, Siouri F, Cohen T, Rode MF, Patterson CS, de Vries M. Excited state intramolecular proton transfer in hydroxyanthraquinones: Toward predicting fading of organic red colorants in art. SCIENCE ADVANCES 2019; 5:eaaw5227. [PMID: 31523708 PMCID: PMC6731090 DOI: 10.1126/sciadv.aaw5227] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Accepted: 08/02/2019] [Indexed: 05/14/2023]
Abstract
Compositionally similar organic red colorants in the anthraquinone family, whose photodegradation can cause irreversible color and stability changes, have long been used in works of art. Different organic reds, and their multiple chromophores, suffer degradation disparately. Understanding the details of these molecules' degradation therefore provides a window into their behavior in works of art and may assist the development of improved conservation methods. According to one proposed model of photodegradation dynamics, intramolecular proton transfer provides a kinetically favored decay pathway in some photoexcited chromophores, preventing degradation-promoting electron transfer (ET). To further test this model, we measured excited state lifetimes of substituted gas-phase anthraquinones using high-level theory to explain the experimental results. The data show a general structural trend: Anthraquinones with 1,4-OH substitution are long-lived and prone to damaging ET, while excited state intramolecular proton transfers promote efficient quenching for hydroxyanthraquinones that lack this motif.
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Affiliation(s)
- J.A. Berenbeim
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - S. Boldissar
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - S. Owens
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - M.R. Haggmark
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - G. Gate
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - F.M. Siouri
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - T. Cohen
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - M. F. Rode
- Institute of Physics, Polish Academy of Sciences, al. Lotników 32/46, PL-02668 Warsaw, Poland
| | - C. Schmidt Patterson
- Getty Conservation Institute, 1200 Getty Center Drive, Suite 700, Los Angeles, CA, USA
| | - M.S. de Vries
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, USA
- Corresponding author.
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19
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Giesbers G, Van Schenck J, Quinn A, Van Court R, Vega Gutierrez SM, Robinson SC, Ostroverkhova O. Xylindein: Naturally Produced Fungal Compound for Sustainable (Opto)electronics. ACS OMEGA 2019; 4:13309-13318. [PMID: 31460459 PMCID: PMC6704441 DOI: 10.1021/acsomega.9b01490] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Accepted: 07/11/2019] [Indexed: 05/14/2023]
Abstract
Organic semiconductors are of interest for (opto)electronic applications due to their low cost, solution processability, and tunable properties. Recently, natural product-derived organic pigments attracted attention due to their extraordinary environmental stability and unexpectedly good optoelectronic performance, in spite of only partially conjugated molecular structure. Fungi-derived pigments are a naturally sourced, sustainable class of materials that are largely unexplored as organic semiconductor materials. We present a study of the optical and electronic properties of a fungi-derived pigment xylindein, which is secreted by the wood-staining fungi Chlorociboria aeruginosa, and its blends with poly(methyl methacrylate) (PMMA) and crystalline nanocellulose (CNC). Optical absorption spectra of xylindein revealed the presence of two tautomers whose structures and properties were established using density functional theory. Pronounced pigment aggregation in polar solvents and in films, driven by intermolecular hydrogen bonding, was also observed. The pigment exhibited high photostability, electron mobility up to 0.4 cm2/(V s) in amorphous films, and thermally activated charge transport and photoresponse with activation energies of ∼0.3 and 0.2 eV, respectively. The dark and photocurrents in xylindein:PMMA blends were comparable to those in pristine xylindein film, whereas blends with CNC exhibited lower currents due to inhomogeneous distribution of xylindein in the CNC.
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Affiliation(s)
- Gregory Giesbers
- Department
of Physics and Department of Wood Science and Engineering, Oregon State University, Corvallis, Oregon 97331, United States
| | - Jonathan Van Schenck
- Department
of Physics and Department of Wood Science and Engineering, Oregon State University, Corvallis, Oregon 97331, United States
| | - Alexander Quinn
- Department
of Physics and Department of Wood Science and Engineering, Oregon State University, Corvallis, Oregon 97331, United States
| | - Ray Van Court
- Department
of Physics and Department of Wood Science and Engineering, Oregon State University, Corvallis, Oregon 97331, United States
| | - Sarath M. Vega Gutierrez
- Department
of Physics and Department of Wood Science and Engineering, Oregon State University, Corvallis, Oregon 97331, United States
| | - Seri C. Robinson
- Department
of Physics and Department of Wood Science and Engineering, Oregon State University, Corvallis, Oregon 97331, United States
| | - Oksana Ostroverkhova
- Department
of Physics and Department of Wood Science and Engineering, Oregon State University, Corvallis, Oregon 97331, United States
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20
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Yu J, Warren WS, Fischer MC. Visualization of vermilion degradation using pump-probe microscopy. SCIENCE ADVANCES 2019; 5:eaaw3136. [PMID: 31245540 PMCID: PMC6588381 DOI: 10.1126/sciadv.aaw3136] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 05/14/2019] [Indexed: 06/09/2023]
Abstract
Here, we demonstrate the use of pump-probe microscopy for high-resolution studies of vermilion degradation. Vermilion (mostly α-HgS), an important red pigment used in historical paintings, blackens over time, and metallic Hg and β-HgS have been implicated as possible degradation products. Conventional analysis techniques have trouble differentiating α- and β-HgS with sufficiently high spatial resolution. However, pump-probe microscopy can differentiate metallic mercury, α- and β-HgS, and map each distribution on the microscopic scale. We studied artificial degradation of α-HgS; femtosecond-pulsed laser irradiation induces an irreversible phase shift of α- to β-HgS, in which the initial presence of β-HgS grains can increase the rate of conversion in their vicinity. Continuous ultraviolet exposure instead generates both liquid Hg and β-HgS, with a conversion rate that increases with elevated temperatures. Last, we reveal the presence of β-HgS as a natural degradation product in discolored vermilion layers in a 14th century Italian painting.
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Affiliation(s)
- Jin Yu
- Department of Chemistry, Duke University, Durham, NC 27708, USA
| | - Warren S. Warren
- Department of Chemistry, Duke University, Durham, NC 27708, USA
- Departments of Radiology, Duke University, Durham, NC 27710, USA
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
- Department of Physics, Duke University, Durham, NC 27708, USA
| | - Martin C. Fischer
- Department of Chemistry, Duke University, Durham, NC 27708, USA
- Department of Physics, Duke University, Durham, NC 27708, USA
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21
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Gao H, Wei P, Liu H, Long M, Fu H, Qu X. Sunlight-Mediated Lead and Chromium Release from Commercial Lead Chromate Pigments in Aqueous Phase. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:4931-4939. [PMID: 30978014 DOI: 10.1021/acs.est.8b06839] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Lead chromate pigments are included in a group of the most widely used pigments, which account for 3% of worldwide lead consumption. This study reports the photoactivity of commercial lead chromate pigment (i.e., chrome yellow) under simulated sunlight. It underwent photodissolution in the presence of organic acid and dissolved organic matter in the aqueous phase, releasing Pb(II) and Cr(III). Pb(II) was released more readily than Cr(III) which mainly formed hydroxides and oxides. The photodissolution can be activated by light with a wavelength <514 nm. The reaction is mediated by the reduction of Cr(VI) in the pigment by self-generated electrons. The kinetics were mainly affected by the electron-hole separation efficiency which can be enhanced by electron donors. The reaction rate decreases with increasing solution pH as the photodissolution process consumes protons. The photodissolution of the chrome yellow pigment was further confirmed in a river water sample under natural sunlight, with 11.28% of lead and 2.56% of chromium released in 7 h. This study highlights the importance of considering photochemical processes in risk assessments and regulations of commercial semiconductor pigments, which are currently based on their solubility.
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Affiliation(s)
- Han Gao
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , Jiangsu 210023 , China
| | - Peiyun Wei
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , Jiangsu 210023 , China
| | - Huiting Liu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , Jiangsu 210023 , China
| | - Mingce Long
- School of Environment Science and Engineering , Shanghai Jiao Tong University , Shanghai 200240 , China
| | - Heyun Fu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , Jiangsu 210023 , China
| | - Xiaolei Qu
- State Key Laboratory of Pollution Control and Resource Reuse, School of the Environment , Nanjing University , Jiangsu 210023 , China
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