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Marco Leona - One of the best experts on this subject based on the ideXlab platform.
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Recent Advances on the Analysis of Polychrome Works of Art: SERS of Synthetic Colorants and Their Mixtures With Natural Dyes
Frontiers Media S.A., 2019Co-Authors: Anna Cesaratto, Marco Leona, Federica PozziAbstract:The development and application of proper sample pretreatments is often a key step toward the successful analysis of dyes used as Artists' materials by surface-enhanced Raman spectroscopy (SERS). Complexation of the organic colorants with metal ions to dye fabrics and produce lake pigments, as well as undesired interactions with other matrix components such as substrate, binding media, fillers, and extenders, are just some of the issues that typically complicate dye identification in minute samples from invaluable ArtWorks and museum objects. These concerns may be addressed by using, prior to SERS analysis, ad-hoc sample pretreatments that, in addition to increasing the technique's sensitivity, favorably affect its selectivity toward certain molecules or molecular classes. The present work describes a newly developed sample pretreatment based on the use of nitric acid that has proven crucial for the successful detection of aniline and xanthene dyes–the first synthetic organic colorants to be used in printing and painting, among other Art forms–in microscopic samples from Works of Art such as a 19th-century silk fabric, paper cut-outs by Henri Matisse, Vincent Van Gogh's Irises, and Japanese woodblock prints. This treatment promotes the hydrolysis of the dye-metal bond in mordant dyes or lake pigments, resulting in a more efficient adsorption of the dye molecules on the SERS-active substrate and, hence, enabling the acquisition of high-quality spectra. In the case of synthetic colorants, this method shows advantages over hydrolysis with hydrofluoric acid–a procedure previously established for the analysis of red lakes prepared from natural dyes. The nitric acid treatment presented here may be integrated into a multi-step methodology that, by exploiting differences in solubility of various dyes and lake pigments, has enabled for the first time to successfully characterize intentional mixtures of natural and synthetic colorants of the xanthene and anthraquinone molecular classes, i.e., eosin Y and carmine, in a selection of Japanese prints of the Meiji era. The present study paves the way for the systematic identification of synthetic dyes in objects of Artistic and archeological interest, even when they are present in mixtures with natural organic colorants
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sample treatment considerations in the analysis of organic colorants by surface enhanced raman scattering
Analytical Chemistry, 2012Co-Authors: Federica Pozzi, John R Lombardi, S Bruni, Marco LeonaAbstract:The introduction of surface-enhanced Raman spectroscopy (SERS) in the field of cultural heritage has significantly improved the analysis of the organic dyes and their complexes that have been used as textile dyes and pigments in paintings and other polychrome Works of Art since antiquity. Over the last five years, a number of different procedures have been developed by various research groups. In this Article, we evaluate the effect of pretreating samples by exposing them to hydrofluoric acid (HF) vapor prior to SERS analysis, a step designed to hydrolyze the dye–metal complexes and increase analyte adsorption on the nanosized metallic support, thus enhancing the SERS signal. Materials studied include pure colorants, commercial lake pigments, and fibers from dyed textiles, as well as actual aged samples, such as microscopic fragments of lakes on paper and ancient pigments and glazes from several Works of Art, covering a wide range of time, from the second century B.C. to the early 20th century. In each ca...
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nondestructive identification of natural and synthetic organic colorants in Works of Art by surface enhanced raman scattering
Analytical Chemistry, 2011Co-Authors: Marco Leona, Peter Decuzzi, Thomas Kubic, Glenn Gates, John R LombardiAbstract:We present a new method based on surface-enhanced Raman scattering (SERS) for the nondestructive identification of organic colorants in objects whose value or function precludes sampling, such as drawings, prints, historic and archeological textiles, handwritten or printed documents, and forensic evidence. A bead of a polymer hydrogel loaded with a solution containing water, an organic solvent, and a chelating agent is used to extract minimal amounts of the colorants from the work of Art for SERS analysis. Using a gel as a medium for the solvent mixture confines its action only to the areas of the work of Art covered by the gel bead. The gel bead is then removed from the work of Art, covered with a drop of Ag colloid, and examined with a Raman microscope. Transfer of the dye from the substrate to the gel does not require removing a sample from the work of Art, therefore preserving the physical integrity of the object. Spectrophotometric color measurements confirm that color change is below the limit perce...
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microanalysis of organic pigments and glazes in polychrome Works of Art by surface enhanced resonance raman scattering
Proceedings of the National Academy of Sciences of the United States of America, 2009Co-Authors: Marco LeonaAbstract:Scientific studies of Works of Art are usually limited by severe sampling restrictions. The identification of organic colorants, a class of compounds relevant for attribution and provenance studies, is further complicated by the low concentrations at which these compounds are used and by the interference of the protein-, gum-, or oil-binding media present in pigment and glaze samples. Surface-enhanced resonance Raman scattering (SERRS) was successfully used to identify natural organic colorants in archaeological objects, polychrome sculptures, and paintings from samples smaller than 25 μm in diameter. The key factors in achieving the necessary sensitivity were a highly active stabilized silver colloid, obtained by the reproducible microwave-supported reduction of silver sulfate with glucose and sodium citrate, and a non-extractive hydrolysis sample treatment procedure that maximizes dye adsorption on the colloid. Among the examples presented are the earliest so far found occurrence of madder lake (in a 4,000 years old Egyptian object dating to the Middle Kingdom period), and the earliest known occurrence in Europe of the South Asian dyestuff lac (in the Morgan Madonna, a 12th century polychrome sculpture from Auvergne, France).
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surface enhanced raman scattering for identification of organic pigments and dyes in Works of Art and cultural heritage material
Sensor Review, 2007Co-Authors: Kui Chen, Marco Leona, Tuan VodinhAbstract:Purpose – Identification and characterization of organic pigments and dyes used in Works of Art and cultural heritage material such as prints, drawings, manuscripts, paintings, and textiles can provide important information for dating, authentication, and conservation treatment of these objects and studying Art history in general. Applications of surface‐enhanced Raman scattering (SERS) for this purpose have recently attracted increasing attention of both academic scientists and museum researchers. This paper aims to review the latest development involving the emerging applications of SERS for the analysis of organic pigments and dyes used in Works of Art and cultural heritage material.Design/methodology/approach – First, the importance of organic pigments and dyes in the studies of Works of Art and cultural heritage material and the challenges in their identification and characterization are briefly summarized. This is followed by a discussion on sampling considerations in the context of Art and archaeol...
Maria Perla Colombini - One of the best experts on this subject based on the ideXlab platform.
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Gas chromatographic-mass spectrometric characterisation of plant gums in samples from painted Works of Art.
Journal of Chromatography A, 2007Co-Authors: Ilaria Bonaduce, H. Brecoulaki, Maria Perla Colombini, A. Lluveras, Vincenzo Restivo, Erika RibechiniAbstract:Abstract This paper presents an analytical GC–MS procedure to study the chemical composition of plant gums, determining aldoses and uronic acids in one step. The procedure is based on the silylation of aldoses and uronic acids, released from plant gums by microwave assisted hydrolysis, and previously converted into the corresponding diethyl-dithioacetals and diethyl-dithioacetal lactones. Using this method only one peak for each compound is obtained, thus providing simple and highly reproducible chromatograms. The analytical procedure was optimised using reference samples of raw plant gums (arabic, karaya, ghatti, guar, locust bean and tragacanth, cherry, plum and peach gums), commercial watercolours and paint layers prepared according to ancient recipes at the Opificio delle Pietre Dure of Florence (Italy). To identify gum media in samples of unknown composition, a decisional schema for the gum identification and the principal component analysis of the relative sugar percentage contents were employed. The procedure was used to study samples collected from wall paintings from Macedonian tombs (4th–3rd centuries bc ) and from the Mycenaean “Palace of Nestor” (13th century bc ) in Pylos, Greece. The presence of carbohydrates was ascertained and plant gum binders (fruit and a mixture of tragacanth and fruit tree gums) were identified in some of the samples.
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GC-MS Characterization of plant gums in samples from painted Works of Art
2007Co-Authors: Ilaria Bonaduce, H. Brecoulaki, Maria Perla Colombini, A. Lluveras, Vincenzo Restivo, Ribechini EAbstract:This paper presents an analytical GC-MS procedure to study the chemical composition of plant gums, determining aldoses and uronic acids in one step. The procedure is based on the silylation of aldoses and uronic acids, released from plant gums by microwave assisted hydrolysis, and previously converted into the corresponding diethyl-dithioacetals and diethyl-dithioacetal lactones. Using this method only one peak for each compound is obtained, thus providing simple and highly reproducible chromatograms. The analytical procedure was optimised using reference samples of raw plant gums (arabic, karaya, ghatti, guar, locust bean and tragacanth, cherry, plum and peach gums), commercial watercolours and paint layers prepared according to ancient recipes at the Opificio delle Pietre Dure of Florence (Italy). To identify gum media in samples of unknown composition, a decisional schema for the gum identification and the principal component analysis of the relative sugar percentage contents were employed. The procedure was used to study samples collected from wall paintings from Macedonian tombs (4th-3rd centuries bc) and from the Mycenaean "Palace of Nestor" (13th century bc) in Pylos, Greece. The presence of carbohydrates was ascertained and plant gum binders (fruit and a mixture of tragacanth and fruit tree gums) were identified in some of the samples
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characterisation of beeswax in Works of Art by gas chromatography mass spectrometry and pyrolysis gas chromatography mass spectrometry procedures
Journal of Chromatography A, 2004Co-Authors: Ilaria Bonaduce, Maria Perla ColombiniAbstract:Pyrolysis (Py) with in situ derivatisation with hexamethyldisilazane-gas chroma-break tography-mass spectrometry (GC-MS) and a gas chromatography-mass spectrometry procedure based on microwave-assisted saponification were used to identify the organic components in small sized beeswax samples. With the latter procedure quantitative recoveries can be made and hydrocarbons, alcohols and omega-1-diols in the neutral fraction, and fatty acids and omega-1-hydroxy acids in the acidic fraction can be efficiently separated and detected. Both procedures were used to characterise a wax anatomic sculpture "The Plague" (1691-1694) by Gaetano Zumbo, resulting in the identification of beeswax and a Pinaceae resin. The GC-MS analysis brought to light some essential differences in beeswax composition between the raw material and the old modelled wax thus giving some clear indications about the recipe used by the sculptor.
Tuan Vodinh - One of the best experts on this subject based on the ideXlab platform.
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surface enhanced raman scattering for identification of organic pigments and dyes in Works of Art and cultural heritage material
Sensor Review, 2007Co-Authors: Kui Chen, Marco Leona, Tuan VodinhAbstract:Purpose – Identification and characterization of organic pigments and dyes used in Works of Art and cultural heritage material such as prints, drawings, manuscripts, paintings, and textiles can provide important information for dating, authentication, and conservation treatment of these objects and studying Art history in general. Applications of surface‐enhanced Raman scattering (SERS) for this purpose have recently attracted increasing attention of both academic scientists and museum researchers. This paper aims to review the latest development involving the emerging applications of SERS for the analysis of organic pigments and dyes used in Works of Art and cultural heritage material.Design/methodology/approach – First, the importance of organic pigments and dyes in the studies of Works of Art and cultural heritage material and the challenges in their identification and characterization are briefly summarized. This is followed by a discussion on sampling considerations in the context of Art and archaeol...
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application of surface enhanced raman scattering sers for the identification of anthraquinone dyes used in Works of Art
Journal of Raman Spectroscopy, 2006Co-Authors: Kui Chen, Marco Leona, Kimchi Vodinh, Fei Yan, Musundi B Wabuyele, Tuan VodinhAbstract:Surface-enhanced Raman scattering (SERS) was investigated for applications in the analysis of anthraquinone dyes used in Works of Art. Two SERS procedures were developed and evaluated with three frequently used anthraquinone dyes, alizarin, carminic acid and lac dye. The first procedure involves coating a layer of silver nanopArticles directly on pieces of filter paper stained with the dyes of interest by thermal evaporation to induce SERS effect. In the second procedure, a SERS-active Ag-Al{sub 2}O{sub 3} substrate was prepared by spin-coating an alumina-nanopArticle layer onto a glass slide to provide the nanostructure of the substrate, followed by thermally evaporating a layer of silver nanopArticles on top of the alumina layer. Aliquots of dye solutions were delivered onto this substrate to be analyzed. Intense SERS spectra characteristic of alizarin, carminic acid and lac dye were obtained using both SERS procedures. The effects of two parameters, the concentration of the alumina suspension and the thickness of the silver nanopArticle layer on the performance of the Ag-Al{sub 2}O{sub 3} substrate were examined with alizarin as the model compound. Comparative studies were conducted between the Ag-Al{sub 2}O{sub 3} substrate and the SERS substrate prepared using Tollens reaction. The Ag-Al{sub 2}O{sub 3} substrate was shownmore » to offer larger enhancement and improved reproducibility than the Tollens substrates. Finally, the potential applicability of the Ag-Al{sub 2}O{sub 3} substrate for the analysis of real Artifact objects was illustrated by the identification of alizarin extracted from a small piece of textile dyed using traditional methods and materials. The limit of detection for alizarin was estimated to be 7 x 10{sup -15} g from tests performed on solutions of known concentration.« less
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application of surface enhanced raman scattering sers for the identification of anthraquinone dyes used in Works of Art
Advanced environmental chemical and biological sensing technologies. Conference, 2005Co-Authors: Kui Chen, Marco Leona, Kimchi Vodinh, Fei Yan, Musundi B Wabuyele, Tuan VodinhAbstract:Surface-enhanced Raman scattering (SERS) was investigated for applications in the analysis of anthraquinone dyes used in Works of Art. Two SERS procedures were developed and evaluated with frequently used anthraquinone dyes, alizarin, carminic acid and lac dye. The first procedure involves the removal of a microscopic fragment containing alizarin from a painting, and a layer of silver nanopArticles was thermally evaporated directly on the fragment to induce SERS signal from alizarin. The applicability of this procedure for analyzing solid samples of color layer from paintings was discussed in detail. In the second procedure, a SERS-active substrate was prepared by spin-coating an alumina-nanopArticle layer onto a glass slide, followed by thermally evaporating a layer of silver nanopArticles on top of the alumina layer. Aliquots of dye solutions were delivered onto this substrate where intense SERS spectra characteristic of alizarin, carminic acid, and lac dye were obtained. The effects of two parameters, the concentration of the alumina suspension, and the thickness of the silver nanopArticle layer, on the performance of the Ag-Al 2 O 3 substrate were examined with alizarin as the model compound. Comparative studies with other common SERS substrates showed larger enhancement and improved reproducibility for the Ag-Al 2 O 3 substrate. The potential applicability of the Ag-Al 2 O 3 substrate for the analysis of real Artifact objects was illustrated by the identification of alizarin extracted from a small piece of textile dyed with traditional methods and materials. The limit of detection for alizarin was estimated to be 7x10 -15 g from tests using solutions of known concentration.
Ilaria Bonaduce - One of the best experts on this subject based on the ideXlab platform.
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Gas chromatographic-mass spectrometric characterisation of plant gums in samples from painted Works of Art.
Journal of Chromatography A, 2007Co-Authors: Ilaria Bonaduce, H. Brecoulaki, Maria Perla Colombini, A. Lluveras, Vincenzo Restivo, Erika RibechiniAbstract:Abstract This paper presents an analytical GC–MS procedure to study the chemical composition of plant gums, determining aldoses and uronic acids in one step. The procedure is based on the silylation of aldoses and uronic acids, released from plant gums by microwave assisted hydrolysis, and previously converted into the corresponding diethyl-dithioacetals and diethyl-dithioacetal lactones. Using this method only one peak for each compound is obtained, thus providing simple and highly reproducible chromatograms. The analytical procedure was optimised using reference samples of raw plant gums (arabic, karaya, ghatti, guar, locust bean and tragacanth, cherry, plum and peach gums), commercial watercolours and paint layers prepared according to ancient recipes at the Opificio delle Pietre Dure of Florence (Italy). To identify gum media in samples of unknown composition, a decisional schema for the gum identification and the principal component analysis of the relative sugar percentage contents were employed. The procedure was used to study samples collected from wall paintings from Macedonian tombs (4th–3rd centuries bc ) and from the Mycenaean “Palace of Nestor” (13th century bc ) in Pylos, Greece. The presence of carbohydrates was ascertained and plant gum binders (fruit and a mixture of tragacanth and fruit tree gums) were identified in some of the samples.
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GC-MS Characterization of plant gums in samples from painted Works of Art
2007Co-Authors: Ilaria Bonaduce, H. Brecoulaki, Maria Perla Colombini, A. Lluveras, Vincenzo Restivo, Ribechini EAbstract:This paper presents an analytical GC-MS procedure to study the chemical composition of plant gums, determining aldoses and uronic acids in one step. The procedure is based on the silylation of aldoses and uronic acids, released from plant gums by microwave assisted hydrolysis, and previously converted into the corresponding diethyl-dithioacetals and diethyl-dithioacetal lactones. Using this method only one peak for each compound is obtained, thus providing simple and highly reproducible chromatograms. The analytical procedure was optimised using reference samples of raw plant gums (arabic, karaya, ghatti, guar, locust bean and tragacanth, cherry, plum and peach gums), commercial watercolours and paint layers prepared according to ancient recipes at the Opificio delle Pietre Dure of Florence (Italy). To identify gum media in samples of unknown composition, a decisional schema for the gum identification and the principal component analysis of the relative sugar percentage contents were employed. The procedure was used to study samples collected from wall paintings from Macedonian tombs (4th-3rd centuries bc) and from the Mycenaean "Palace of Nestor" (13th century bc) in Pylos, Greece. The presence of carbohydrates was ascertained and plant gum binders (fruit and a mixture of tragacanth and fruit tree gums) were identified in some of the samples
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characterisation of beeswax in Works of Art by gas chromatography mass spectrometry and pyrolysis gas chromatography mass spectrometry procedures
Journal of Chromatography A, 2004Co-Authors: Ilaria Bonaduce, Maria Perla ColombiniAbstract:Pyrolysis (Py) with in situ derivatisation with hexamethyldisilazane-gas chroma-break tography-mass spectrometry (GC-MS) and a gas chromatography-mass spectrometry procedure based on microwave-assisted saponification were used to identify the organic components in small sized beeswax samples. With the latter procedure quantitative recoveries can be made and hydrocarbons, alcohols and omega-1-diols in the neutral fraction, and fatty acids and omega-1-hydroxy acids in the acidic fraction can be efficiently separated and detected. Both procedures were used to characterise a wax anatomic sculpture "The Plague" (1691-1694) by Gaetano Zumbo, resulting in the identification of beeswax and a Pinaceae resin. The GC-MS analysis brought to light some essential differences in beeswax composition between the raw material and the old modelled wax thus giving some clear indications about the recipe used by the sculptor.
Piero Baglioni - One of the best experts on this subject based on the ideXlab platform.
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surfactants mediate the dewetting of acrylic polymer films commonly applied to Works of Art
ACS Applied Materials & Interfaces, 2019Co-Authors: Costanza Montis, Michele Baglioni, Debora Berti, Kaloian Koynov, Andreas Best, Hansjurgen Butt, Piero BaglioniAbstract:The removal of hydrophobic polymer coatings from Artistic surfaces is a ubiquitous challenge in Art restoration. Over the years, nanostructured fluids (NSFs), aqueous surfactant solutions containin...
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a triton x 100 based microemulsion for the removal of hydrophobic materials from Works of Art saxs characterization and application
Materials, 2018Co-Authors: Michele Baglioni, Rodorico Giorgi, Emiliano Fratini, Giovanna Poggi, Giulia Ciolli, Piero BaglioniAbstract:The removal of hydrophobic materials from a porous support, such as wax stains on wall paintings, is pArticularly challenging. In this context, traditional methods display several drawbacks. The limitations of these methods can be overcome by amphiphile-based aqueous nanostructured fluids, such as micellar solutions and microemulsions. In this study, a microemulsion for the removal of wax spots from Artistic surfaces was formulated. The nanostructured fluid includes a non-ionic surfactant, i.e., Triton X-100, and two apolar solvents, namely p-xylene and n-nonane. The solvents were selected on the basis of solubility tests of three waxes in several organic solvents. The nanostructured fluid was characterized by means of small-angle X-rays scattering (SAXS) and the information about micelle structure was used to understand the interaction between the microemulsion and the selected waxes. The microemulsion was then tested during the restoration of the frescoes in the Major Chapel of the Santa Croce Basilica in Florence, Italy. After some preliminary tests on fresco mockups reproduced in the laboratory, the nanostructured fluid was successfully used to clean some wax deposits from the real paintings, hardly removable with traditional physico-mechanical methods.
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an amine oxide surfactant based microemulsion for the cleaning of Works of Art
Journal of Colloid and Interface Science, 2015Co-Authors: Michele Baglioni, Yareli Jaidar Benavides, Debora Berti, Rodorico Giorgi, Uwe Keiderling, Piero BaglioniAbstract:Surfactant-based aqueous fluids, such as micellar solutions and microemulsions, are effective, safe and selective media for cleaning operations in conservation of cultural heritage. The search for better-performing systems and eco-friendly cleaning systems is currently a major goal in conservation science. We report here on a ternary o/w microemulsion, composed of diethyl carbonate (DC) as the oil phase and N,N-Dimethyldodecan-1-amine oxide (DDAO) as the surfactant. DDAO is a well known and widely used detergent and solubilizing agent, selected here for its degradability and eco-compatibility. Due to its nonionic/cationic nature, it can be used also when nonionic-based formulations become ineffective because of clouding and phase separation. Moreover, DDAO is insensitive to the presence of divalent metal ions, usually abundant in wall paintings substrates. Small-Angle Neutron Scattering (SANS) provided detailed information about the nanostructure of the surfactant aggregates. Finally, the cleaning effectiveness of the nanofluid was assessed both on fresco mock-ups and on real wall paintings conserved in the archeological site of Tulum, Mexico. Here, conservators successfully used the microemulsion to remove naturally aged films of complex polymer mixtures from the Works of Art surface.
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nanostructured fluids from degradable nonionic surfactants for the cleaning of Works of Art from polymer contaminants
Soft Matter, 2014Co-Authors: Michele Baglioni, Debora Berti, Uwe Keiderling, Martina Raudino, Romain Bordes, Krister Holmberg, Piero BaglioniAbstract:Nanostructured fluids containing anionic surfactants are among the best performing systems for the cleaning of Works of Art. Though efficient, their application may result in the formation of a precipitate, due to the combination with divalent cations that might leach out from the Artifact. We propose here two new aqueous formulations based on nonionic surfactants, which are non-toxic, readily biodegradable and insensitive to the presence of divalent ions. The cleaning properties of water-nonionic surfactant-2-butanone (MEK) were assessed both on model surfaces and on a XIII century fresco that could not be cleaned using conventional methods. Structural information on nanofluids has been gathered by means of small-angle neutron scattering, dynamic light scattering and nuclear magnetic resonance with diffusion monitoring. Beside the above-mentioned advantages, these formulations turned out to be considerably more efficient in the removal of polymer coatings than those based on anionic surfactants. Our results indicate that the cleaning process most likely consists of two steps: initially, the polymer film is swollen by the MEK dissolved in the continuous domain of the nanofluid; in the second stage, surfactant aggregates come into play by promoting the removal of the polymer film with a detergency-like mechanism. The efficiency can be tuned by the composition and nature of amphiphiles and is promoted by working as close as possible to the cloud point of the formulation, where the second step proceeds at maximum rate.
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nanoscience for Art conservation oil in water microemulsions embedded in a polymeric network for the cleaning of Works of Art
Angewandte Chemie, 2009Co-Authors: Emiliano Carretti, Debora Berti, Emiliano Fratini, Piero BaglioniAbstract:parent, and the cleaning action can be monitored visually and controlled during the application. The idea that underpinned this study was to produce a complex system in which the structure and superior performance of the microemulsion were preserved, and the diffusion of its droplets was controlled by the mesh size and viscosity of the polymeric network. With this view, we analyzed possible changes induced by hmHEC in the nanostructure of the o/w mE and studied the interactions between the microemulsion embedded in the hmHEC network (M1/ hmHEC) and the organic materials to be removed from the
