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Silane-based materials are used for the protection of heritage and modern buildings. A versatile method is developed to tune the wetting properties of a typical silane-based material from hydrophobicity to superamphiphobicity, thus enhancing the protective efficacy against rainwater and organic pollutants. A commercially available silane product is blended with a fluoropolymer to lower the surface energy and silica (SiO2) nanoparticles to affect the surface morphologies of the produced coatings on marble. Contact angles of water and oil drops are measured on the coating surfaces which were prepared using 16 different combinations of fluoropolymer and nanoparticle concentrations. It is shown that the synergistic effect of surface structure and chemistry can lead to the production of coatings that possess superamphiphobic properties. The wetting properties of a selected non-wettable coating are further characterised using a custom-made, fully-automated device (Kerberos) which monitors simultaneously the deformation of the liquid interface, spreading and sliding of the drop along the sample surface during tilting. Several tests are carried out to evaluate the durability of the selected superamphiphobic coating, offering overall promising results. The versatile method can be used to impart superamphiphobicity to the surfaces of various materials. The method developed herein can be adopted to tune the wetting properties of other silane-based commercial products which are used for the protection of buildings.

High Performance Liquid Chromatography coupled to a Diode-Array-Detector (HPLC-DAD) is used to investigate samples which were extracted from ancient Egyptian textiles (4th–5th c. AD) of the Museum of Faculty of Archaeology, Cairo University. Madder is identified in several samples. According to semi-quantitative results, which are obtained from HPLC peak areas measured at 254 nm, madder that is rich in purpurin and poor in alizarin is identified in samples which were treated (i) only with madder and (ii) with madder and either indigo/woad (Indigofera species and other/Isatis tinctoria L.) or weld (Reseda luteola L.). The madder dye used in these samples could have been originated from Rubia peregrina L. However, the possible use of Rubia tinctorum L. (or other plants of the Rubiaceae family) by the Egyptian dyers cannot be ruled out, particularly if methods were developed by the ancient dyers to affect and control the relative composition of madder dye. The HPLC peak area ratio of alizarin versus purpurin is very high (&gt, 2.2) for samples which were treated with madder (probably originated from R. tinctorum) and a tannin source. Finally, in some samples, only indigoid dyes (indigo/woad) are identified.

The preservation of cultural heritage monuments and artifacts requires the development of methods to produce water-repellent materials, which can offer protection against the effects of atmospheric water. Fluorosilanes are a very promising class of materials, as they act as precursors for the formation of low surface energy polymer networks. 1H,1H,2H,2H-perfluorooctyl-triethoxysilane is applied on marble, wood and the surfaces of other materials, such as glass, silicon wafer, brass, paper and silk. According to the measurements of static water contact angles, it is reported that superhydrophobicity and enhanced hydrophobicity are achieved on the surfaces of coated marble and wood, respectively. Hydrophobicity and hydrophilicity were observed on the treated surfaces of the other materials. More important, water repellency is achieved on any hydrophobic or superhydrophobic surface, as revealed by the very low sliding angles of water drops. The study is accompanied by colorimetric measurements to evaluate the effects of the treatment on the aesthetic appearances of the investigated materials. Finally, the capillary absorption test and a durability test are applied on treated wood and marble, respectively.

Non-wettable surfaces have been uninterruptedly studied during the 20th century [...]

The effects of harsh UV radiation (λ = 254 nm) on wool and silk dyed with Hexaplex (Murex) trunculus extract are investigated using HPLC-DAD, colourimetry, SEM and FTIR. Indigotin, 6-bromoindigotin, 6,6′-dibromoindigotin and 6,6′-dibromoindirubin were quantified by an efficient HPLC-DAD method which was validated in terms of linearity, detection and quantification limits, precision and accuracy. Under optimal conditions, the developed analytical scheme offers limits of detection in the range 0.02–0.12 μg mL−1 and satisfactory linearity up to 5.0 μg mL−1. The purple dyes, extracted from the wool and silk fibres, were analysed by the established HPLC method, using the standards addition approach. To evaluate the matrix effect, the matrix-induced signal suppression/enhancement was determined. The accuracy was evaluated by recovery experiments. The effect of the UV light was initially dramatic, leading to (i) a rapid decrease in the amounts of the four shellfish compounds in the wool/silk fibres and (ii) severe colour changes of the dyed fibres. After extensive (>10 days) exposure in harsh UV light, only slight changes in the dye composition and the colour of the fibres were observed. Overall, larger reductions are reported in the amounts of the dibrominated molecules, whereas indigotin and 6-bromoindigotin appear to be more stable against the UV radiation. However, it is reported that the % relative composition of the shellfish dye is practically unaffected by the degradation process. Finally, the UV-induced structural and chemical changes of the wool and silk fibres were investigated using SEM and FTIR, respectively.

The efficacy of poly(vinyl alcohol) and borax (PVA-b) films to remove varnishes of natural resins from paint samples is studied. Samples prepared according to the egg tempera technique were varnished with mastic, dammar (triterpenoid resins), sandarac, copal, colophony (diterpenoid resins), and shellac and were subjected to artificially accelerated UV-aging conditions. The efficacy of the PVA-b films to remove the aged varnishes, thus cleaning the sample surfaces without using any organic solvent, is evaluated using optical microscopy in visible and UV light, optical coherence tomography, Fourier transform infrared spectroscopy, and Raman spectroscopy. The characterization of the PVA-b films is extended to rheological measurements, whereas water contact angle and pH measurements provide evidence about the formation of polar, hydrophilic groups during aging. Concerns related to potential side effects of the suggested cleaning method are addressed such as the effect of the PVA-b film on the egg tempera paint layer and the possible film residue left on a sample surface after the removal of the PVA-b film. It is reported that the method provides very good results in the removal of the triterpenoid resins and shellac, whereas the removal of the diterpenoid resins is accompanied by noticeable side effects. The suggested cleaning method was applied to remove old shellac varnishes from two icons which date to the nineteenth c. Τhe varnish in one of the two icons was in a very poor condition consisted of a very dark layer of shellac and dirt with intense craquelure. In this case, the cleaning process was modified and reinforced by heating the PVA-b film in situ.

Proyecto Art-Risk, BIA2015-64878-R, This study conducted a comparison between biocide treatments based on nanoparticles of silver, copper, ZnO, TiO2 and silver/ TiO2 nanocomposites to analyse their capability to inhibit microalgal fouling on stone buildings. Biofouling is one of the main alterations on stone façades, causes degradation of their constituent materials and interferes with their aesthetic values. The proposed treatments were tested on a limestone from the historic quarry of Estepa (Spain), widely used as construction material in the South of Spain. The applicability of the treatments was evaluated by colorimetry. The biocidal effectiveness of the nanoparticles was studied on stone surfaces by multispectral imaging, digital image analysis and optical coherence tomography. This is a low-cost and efficient protocol to validate biocidal treatments for limestone monuments, and our results demonstrate the potential of silver and ZnO nanoparticles as a protective treatment for stone façades. The results have implications for practitioners working on historic buildings., Department of Physical, Chemical and Natural Systems, Pablo de Olavide University, Department of Management and Conservation of Ecclesiastical Cultural Heritage Objects, University Ecclesiastical Academy of Thessaloniki, Preprint

Saint Demetrius of Stomion is a historical monastery placed in the geographical area of Larissa town, Greece, with a remarkable presence from its founding until nowadays. The monastery's present catholicon (main church) has been dated in the 16th century and its surviving wall paintings were constructed in 1758. In addition to the characterization of the materials applied, the purpose of this study is to determine the existence of a sole pictorial phase, that of the mid-18th century, or the occurrence of overpaintings. Additionally, the present study aims to begin the establishment of the documentation of materials and techniques of the late post-Byzantine iconographic guilds, which acted in Central and Northern Greece. The collected samples were analyzed by means of microscopic, spectroscopic and thermogravimetric methods. The use of fresco technique is implied by the major participation of calcium carbonate in all of the painting layers, its main contribution in the plaster layers and the microstratigraphic analysis of the samples' cross-sections, while the scarce and local presence of a proteinaceous material implies the limited use of egg-tempera technique for the highlights. The pigment analysis shows that mostly traditional pigments were used, including cinnabar, ferrous pigments (ochre, sienna, umber), minium, Naples yellow, massicot/litharge, green earth (celadonite), malachite, carbon and bone black, calcite, kaolinite and lead white. The absence of modern pigments, the consistency of all samples regarding microstratigraphy and applied materials, and the lack of the extensive use of an organic medium, strongly suggest the lack of overpaintings.

This chapter provides a brief review of methods devised to impart superhydrophobicity to textiles using nanoparticles, combined usually with other materials, as hydrophobing agents. Nanoparticles have opened new avenues for the production of multifunctional textiles, and therefore in some of the reviewed methods, superhydrophobic textiles show simultaneously superoleophobicity and/or antimicrobial/bacterial activity, as discussed in detail. Other properties that are important for the textile industry (e.g., durability, transparency, UV shielding, air permeability, etc.) are mentioned in the discussion. Finally, attention focuses also in the application of treated textiles with extreme wetting properties in water cleaning and harvesting which are top priorities for the next several decades, according to the UNESCO guidelines.

Waterborne polysiloxane coatings can obtain superhydrophobic and water-repellent properties by embedding oxide nanoparticles into the organosilicon matrix during coating deposition. The nanoparticles induce surface roughness resulting to extreme wetting properties. This general strategy is demonstrated and implemented in this case study where a commercial water-based emulsion of silanes/siloxanes is mixed with silica nanoparticles (7 nm) and brushed on mortar, ceramic, and wood. These materials are found in monuments and outdoor objects of the cultural heritage, which are subjected to degradation by rainwater and humidity. Water drops on the produced polysiloxane–silica coatings correspond to large static contact angles (>150 degrees) and small sliding angles (

High-performance liquid chromatography coupled to a diode-array detector (HPLC-DAD) is used to investigate 30 samples which were removed from 27 ancient Egyptian fabrics of the Fill-Trevisiol collection. Attention is focused in this paper on fabrics of the Roman and Byzantine periods, with red and deep violet–blue wool weft threads which are Z-spun. The following dyes are identified in fabrics which date to the Roman period (first–fifth c. ad): mollusc purple, madder, and indigo/woad (Indigofera species and other, Isatis tinctoria L.). The results for the Byzantine (fifth–seventh c. ad) fabrics are richer in terms of identified dyes: apart from the three aforementioned dyes, the use of kermes (Kermes vermilio Planchon) and cochineal is revealed as the two coccid dyes have been detected in six Egyptian–Byzantine fabrics. Moreover, a yellow dye (probably Reseda luteola L.) is identified in one sample. Finally, samples taken from two fabrics, which date to the Islamic period, were dyed using indigo/woad and lac (Kerria lacca, Kerr). Mixing madder and indigo/woad to imitate true purple was a common practice in ancient Egypt and this is confirmed by the HPLC results in several samples. Semi-quantitative results are obtained from the HPLC peak areas and lead to the following conclusions. Madder dyes which were rich or poor in alizarin, compared to purpurin, and could have been therefore obtained from Rubia tinctorum L. and Rubia peregrina L., respectively are detected in Byzantine fabrics. Only alizarin-rich madder dyes are identified in some samples from Roman fabrics, but in some other samples the relative alizarin-to-purpurin ratio cannot be measured with confidence. Cochineal is found in two samples. The biological source of cochineal (Porphyrophora hamelii Brandt) is possible to be chemically identified only in one sample. The HPLC results of the molluscan dye detected in a Roman fabric are compared with the relative compositions of extracts of the three Mediterranean molluscs leading to the speculation that the Roman purple sample was probably dyed using Hexaplex trunculus L. The molluscan dye was furthermore detected in a Byzantine sample where it was combined with madder. Finally, it is reported that the standard (hydrochloric) acid hydrolysis method which is commonly applied to extract dyes from archaeological samples does not have any noticeable effect on the relative composition of the molluscan dye.

This study explores the authentication of a bronze statue by means of the evaluation of technical evidence and investigation of patinas formation. The statue was identified by the police as a product of illicit excavation and handed to the Archaeological Museum of Thessaloniki. The visual examination reveals technical features that are consistent with those commonly found on ancient bronze statues while the physicochemical character of the corrosion was in accordance with typical bronze corrosion mechanisms (decuprification). Original features like the metal microstructure were detected on the corrosion layers, showing the complexity and long lasting character of their formation. The metal composition was determined by XRF and the corrosion products were analysed by XRF and SEM-EDS.

A decorated and carved wooden door of the late Byzantine period (14th Century), which belongs to the Dionysiou Monastery in Mount Athos, Greece, constitutes an important relic of valuable technological information due to its construction technology and history. Seventeen (17) samples detached from the door are studied using optical microscopy, scanning electron microscopy (SEM) with energy dispersive X-ray analysis (SEM-EDX), and micro-Raman and FTIR spectroscopy. The following materials are identified in the cross sections of the door samples using micro-Raman spectroscopy: orpiment, lead white, red lead, red ochre, cinnabar, carbon black, gypsum, anhydrite, and calcite, and an organic colourant of the indigoid family. SEM-EDX studies supported to the aforementioned Raman results. Interestingly, a combination of inorganic and organic colourants was detected. The main goals of this particular study were to: (a) reveal the colour palette and materials, (b) identify the type of varnish and its condition, and (c) contribute to future restoration processes and aid conservators in selecting compatible restoration materials.

A HPLC method coupled with diode array detector was developed and validated for the quantitation of alizarin, apigenin, carminic acid, curcumin, ellagic acid, emodin, fisetin, kaempferide, kaempferol, kermesic acid, morin, purpurin, quercetin and sulfuretin which are components of several natural dyes. 1- Hydroxyanthraquinone was selected as internal standard. The compounds were separated under gradient elution on a RP-column (Altima C18, 250 mm x 3.0 mm i.d., 5 μm) with a mobile phase consisting of solvent A: H2O + 0.1% (v/v) trifluoroacetic acid and solvent B: acetonitrile + 0.1% (v/v) trifluoroacetic acid. The method was validated in terms of linearity, limits of detection and quantitation, accuracy, precision, ruggedness and robustness and applied to the analysis of silk dyed with buckthorn (Rhamnus trees), cochineal (Dactylopius coccus Costa), madder (Rubia tinctorum L.), turmeric (Curcuma longa L.) and young fustic (Cotinus coggygria Scop). Furthermore, dyed silk samples were subjected to artificially accelerated ageing conditions induced by UV radiation. The effect of the latter on the quantities of the aforementioned compounds was monitored, except for apigenin, kermesic acid and morin.

Quantitative HPLC and colorimetry are used to study color variations in dyeings with indigo, 6-bromoindigo, and 6,6′-dibromoindigo, the main components of the historic dye Tyrian purple. For the first time, visible light is identified conclusively as a cause of debromination of the leuco form of 6-bromoindigo. A dyeing run using 6-bromoindigo alone is found to yield a dyed fabric containing large amounts of indigo, when the vat is exposed to visible light. The extent of debromination is dependent upon the pH of the dye bath and also the source of the visible light. This information allowed development of a dyeing procedure which is demonstrated to give consistent colors through two passes. Quantitative HPLC analysis of extracts from the dyed fabrics indicates that the leuco form of 6-bromoindigo vs. the leuco forms of indigo and 6,6′-dibromoindigo has the strongest affinity for wool fabric. This is postulated to be due to attractive electrostatic interactions between the leuco form of 6-bromoindigo and wool.

A tuneable green process of textile cleaning is being optimized. The cleaning is achieved with supercritical carbon dioxide and an aqueous suspension as co-solvent. We managed to lower the operational pressure and examine the effect of the Ca(OH) 2 concentration on the cleaning result. Soil and colour migration, particle size distribution and their possible effect on the cleaning result as well as the CaCO 3 particle deposition have been studied. The optimal operational pressure is 150 bar at 40 °C while the proposed Ca(OH) 2 concentration is 5% w/w. The cleaning efficiencies reported on olive rabbit skin glue and beetroot paste are 97%, 99% and 97% respectively. No colour and/or soil migration to other parts of the textiles was observed. The optimized process has been successfully applied on textiles infected with Aspergillus Niger fungi. The combination of the exposure of the textile in a Ca(OH) 2 aqueous dispersion and the exposure in scCO 2 and CaCO 3 particles produced in situ leads to textile⿿s disinfection. No chemical disinfectants are used nor required. The proposed, optimized process is a tuneable green cleaning process which can be easily adjusted to any type of soiling. Characterization of the soiled and cleaned textiles was performed by means of weight loss (soil removal efficiency), colour measurements, optical microscopy, XRF analysis, UV⿿vis absorption and imaging techniques.

The aim of this study is the characterization of a portable icon of Virgin Mary “Eleousa”, from the village of Kleidi, Northern Greece. The icon is dated in the second half of 19th century, and its stylistic features typify it as a representative example of post-Byzantine folk ecclesiastical art of Northern Greece. Micro-samples of the painting and ground layers were analyzed by means of microscopic and spectroscopic methods (optical microscopy, μ-FTIR, μ-Raman and SEM-EDS). The combination of the applied characterization methods permitted the detailed examination of the stratigraphy and the materials of the icon. The identified pigments are minium, hematite (red ochre), Prussian blue and carbon black. Egg tempera was the applied technique and the gilding was made with golden leaves applied using the water gilding technique (bole). This study belongs to a project which aims to the documentation of the materials and techniques of late post-Byzantine Northern and Central Greek artistic guilds.

Tetraethyl orthosilicate (TEOS) is extensively used in the conservation of stone-built cultural heritage, which is often subjected to water-induced degradation processes. The goal of this study was to produce and study a TEOS-based material with the ability to repel liquid water. A sol solution of TEOS and 1H,1H,2H,2H-perfluorooctyl triethoxysilane (FAS) was prepared and deposited on marble. The static contact angles (CAs) of water drops on the coated marble surface were &gt, 170&deg, and the sliding angles (SA) were &lt, 5&deg, suggesting that superhydrophobicity and water repellency were achieved on the surface of the synthesized TEOS-based coating. FTIR and SEM-EDS were employed to characterize the produced coating. The latter offered good protection against water penetration by capillarity, reducing the breathability of marble only by a small extent and with practically no effect on its aesthetic appearance. The durability of the coating was evaluated through various tests that provided very promising results. Finally, the versatility of the method was demonstrated as the TEOS-based coating was successfully deposited onto glass, brass, wood, silicon, paper and silk, which obtained extreme wetting properties.

A water soluble siloxane emulsion enriched with silica nanoparticles (7 nm) is sprayed on white marble and sandstone without the use of any organic solvent. A continuous rough structure, composed of numerous micro/nano structures, is formed at low nanoparticle concentration. Drops of water, glycerol, ethylene glycol and oil on coatings, which were prepared using siloxane and 2% w/w nanoparticles correspond to high static contact angles (>150o). Moreover, water and oil drops correspond to low tilt contact angles (2% w/w) is used for the production of the coatings, as large grooves are formed. These grooves have no significant effect on the contact angles of water and glycerol drops which correspond to high surface tensions. However, the grooves are responsible for a transition from the above described Cassie-Baxter state to the Wenzel state, which was observed for ethylene glycol and oil drops, that are liquids of low surface tensions.The evaporation of water drops on structured coatings prepared using siloxane and 2% w/w nanoparticles is monitored. It is shown that a set of stick-slip events of the contact line, accompanied by a decrease in contact angle, dominates the evaporation process. Keywords: superhydrophobic, superoleophobic, water repellent, contact angle, drop evaporation, cultural heritage

The fabrication of protective coatings on silk with special properties is presented. A water soluble siloxane emulsion enriched with silica nanoparticles (7 nm) is sprayed on silk, without the use of any organic solvent. By adjusting the nanoparticle concentration, treated silk obtains (i) superhydrophobic and superoleophobic properties, as evidenced by the high static contact angles of water and oil droplets (>150°) and (ii) water and oil repellent properties, as supported by the corresponding low tilt contact angles (

The main churches of three monasteries in Thessalia, Central Greece, were decorated with wall paintings in the post-Byzantine period. The main goal of the present study is to characterize the inorganic and organic materials present in the paint layers of areas that have been gilded. Optical microscopic examination was carried out on samples taken from the gilded decoration of the paintings to view their layer build-up. The combined use of micro Fourier transform infrared (FT-IR) and micro-Raman spectroscopy led to the detection of the pigments and the binding media used. The results from specimens taken from different wall paintings were compared with each other to observe their differences and similarities. The three investigated churches are believed to have been painted by the same iconographer, Tzortzis, who however has only been identified in only one of them. The comparison led to the conclusion that there are many similarities in the painting materials used and the general methodology adopted and, therefore, this study offers support to the belief that the mural paintings of the three monasteries could have been painted by the same iconographer. While not authenticating the two painting as being by Tzortzis, the results provide further critical material that is consistent with this attribution. However, this statement must be carefully considered because the pigments identified have been commonly and diffusely used in historic mural paintings.

In the last two decades, materials of extreme wetting properties have received significant attention, as they offer new perspectives providing numerous potential applications [...]

Decohesion of building materials caused by weathering translates into the need for recurrent interventions with consolidating treatments that often turn out useless for desired long-term consolidation owing to their poor in-depth penetration. Due to this, it is important to develop new products that allow evaluating their penetration in situ. In this work, three commercial consolidants (Estel 1200®, NanoEstel® and Nanorestore®) widely used in stone conservation were compared with a new consolidant nanocomposite (Nanorepair UV). This nanocomposite, which consists of calcium hydroxide nanoparticles doped with zinc oxide quantum dots, allows both consolidation and in situ evaluation of the penetration depth of the treatment, a key variable to assess effectiveness when an in-depth consolidation is required. The treatments were assayed on limestones from two quarries widely used in the construction of monuments in southern Spain. The development of new products devoted to our Cultural Heritage entails specific requirements such as effectiveness, durability and compatibility with the original materials without changing their aesthetic features. The compatibility was studied by colorimetric methods and SEM images to detect the formation of surface layers. The effectiveness of the treatments was quantified by both peeling test and ultrasound propagation speed. Finally, the durability was studied by an accelerated weathering test induced by salt crystallization. The results showed that nanolimes had higher effectiveness and better durability than silica treatments as consolidants for limestones. In addition, Nanorepair UV provided an additional functionality since it allowed measuring the treatment penetration depth in a simple and economical way, by means of ultraviolet illumination, while allowed to distinguish treated areas from untreated ones.

Calcium hydroxide (Ca(OH2)) nanoparticles are produced following an easy, ion exchange process. The produced nanoparticles are characterized using transmission electron microscopy (TEM) and Fourier- transform infrared spectroscopy (FTIR) and are then dispersed in an aqueous emulsion of silanes/siloxanes. The dispersions are sprayed on marble and the surface structures of the deposited coatings are revealed using scanning electron microscopy (SEM). By adjusting the nanoparticle concentration, the coated marble obtains superhydrophobic and water repellent properties, as evidenced by the high static contact angles of water drops (> 150°) and the low sliding angles (< 10°). Because Ca(OH)2 is chemically compatible with limestone-like rocks, which are the most common stones found in buildings and objects of the cultural heritage, the produced composite coatings have the potential to be used for conservation purposes. For comparison, the wetting properties of another superhydrophobic and water repellent coating composed of the same siloxane material and silica (SiO2) nanoparticles, which were commonly used in several previously published reports, were investigated. The suggested siloxane+Ca(OH)2 composite coating offers good protection against water penetration by capillarity and has a small effect on the aesthetic appearance of marble, according to colorimetric measurements.

Paraloid B72 is a very important product in the conservation and restoration science and practice, particularly for cultural heritage and artistic objects. It is an inherent hydrophilic copolymer of methyl acrylate and ethyl methacrylate. In this study, superhydrophobicity is induced in Paraloid coatings by embedding silica (SiO2) nanoparticles into the polymer matrix, at appropriate concentration. Coatings are deposited on glass, marble, brass and wood. Nanoparticles form microscale clusters which enhance the roughness of the polymer surface. Nanoparticles have negligible, moderate and enormous effects on the colour of treated marble, wood and brass, respectively. The Paraloid + SiO2 composite coatings show good chemical stability.

The cross-section stratifications of samples, which were removed from six icons, are studied using optical microscopy, micro-Raman spectroscopy, and micro-Fourier transform infrared (FT-IR) spectroscopy. The icons, dated from the 14th to 19th centuries, are prominent examples of Byzantine painting art and are attributed to different artistic workshops of ​​northern Greece. The following materials are identified in the cross-sections of the icon samples using micro-Raman spectroscopy: anhydrite; calcite; carbon black; chrome yellow; cinnabar; gypsum; lead white; minium; orpiment; Prussian blue; red ochre; yellow ochre; and a paint of organic origin which can be either indigo ( Indigofera tinctoria L. and others) or woad ( Isatis tinctoria L.). The same samples are investigated using micro-FT-IR which leads to the following identifications: calcite; calcium oxalates; chrome yellow; gypsum; kaolinite; lead carboxylates; lead sulfate (or quartz); lead white; oil; protein; Prussian blue; saponified oil; shellac; silica; and tree resin. The study of the cross-sections of the icon samples reveals the combinations of the aforementioned inorganic and organic materials. Although the icons span over a long period of six centuries, the same stratification comprising gypsum ground layer, paint layers prepared by modified “egg tempera” techniques (proteinaceous materials mixed with oil and resins), and varnish layer is revealed in the investigated samples. Moreover, the presence of three layers of varnishes, one at the top and other two as intermediate layers, in the cross-section analysis of a sample from Virgin and Child provide evidence of later interventions.

Silica nanoparticles were dispersed in an aqueous emulsion of alkoxy silanes and organic fluoropolymer. The dispersion was sprayed onto white marble and sandstone. The deposited composite coatings exhibited (i) superhydrophobicity and superoleophobicity, as evidenced by the high (>150°) static contact angles of water and oil drops as well as (ii) water and oil repellency according to the low (

A method to produce multifunctional coatings for the protection of silk is developed. Aqueous dispersion, free of any organic solvent, containing alkoxy silanes, organic fluoropolymer, silane quaternary ammonium salt, and silica nanoparticles (7 nm in mean diameter) is sprayed onto silk which obtains (i) superhydrophobic and superoleophobic properties, as evidenced by the high contact angles (>150°) of water and oil drops and (ii) antimicrobial properties. Potato dextrose agar is used as culture medium for the growth of microorganisms. The protective coating hinders the microbial growth on coated silk which remains almost free of contamination after extensive exposure to the microorganisms. Furthermore, the multifunctional coating induces a moderate reduction in vapor permeability of the treated silk, it shows very good durability against abrasion and has a minor visual effect on the aesthetic appearance of silk. The distinctive roles of the silica nanoparticles and the antimicrobial agent on the aforementioned properties of the coating are investigated. Silica nanoparticles induce surface structures at the micro/nano-meter scale and are therefore responsible for the achieved extreme wetting properties that promote the antimicrobial activity. The latter is further enhanced by adding the silane quaternary ammonium salt in the composition of the protective coating.

The goal of the study is the identification of pigments and other materials contained in wall paintings of three Macedonian tombs which date back to the fourth to third century BC: the tomb I of Dion, the tomb IV of Dion, and the tomb A (Heuzey). The investigation is carried out in two phases. First, portable X-ray fluorescence (XRF) spectroscopy is used for in situ measurements. In the second phase, 12 microsamples which were removed from damaged areas of the wall paintings are investigated using optical microscopy, micro-Raman, and micro-FTIR spectroscopy.

Representing St. Athanasios of Alexandria, and found buried a century ago in Northern Greece, the portable icon under study displays a rare substrate; its panel is a unique example of a wooden instrument in secondhand use. In particular, a threshing board, a common in the Mediterranean basin agricultural instrument, was used as the panel of the icon. Optical and UV microscopy, X-ray radiography, SEM-EDS microscopy, and μ-FTIR spectroscopy were employed to determine the state of preservation and to identify the applied materials and pigments. The stratigraphy of the painting includes the wooden substrate, a textile support of cotton fibers, and the ground layers which consist of anhydrite, gypsum, and rabbit skin glue. The gilding consists of a gold and silver alloy foil, applied with the use of bole. A simple palette of red, brown, white, and black colors was used for the painting layers. Ochre, minium, calcite, lead white, and bone black are the identified pigments. The identification of egg yolk implies the use of egg tempera technique. The remaining traces of varnish were identified as of plant origin, most probably mastic. All of the icon’s characteristics – the materials and pigments and the stratigraphy (e.g., mastic varnish, cotton textile support, bole, repousse halo, and egg tempera technique) – are typical of the seventeenth century.

Superhydrophobic and water-repellent coatings can have numerous applications including the protection of monuments and other stone objects of the cultural heritage. In this study, the fundamental observations, concepts, and equations provided by T. Young, R.N. Wenzel, A.B.D. Cassie, S. Baxter, and other researchers on the wettability of solid surfaces are briefly described. Moreover, some interesting methods which were devised to induce enhanced hydrophobicity and water repellency to natural stone are briefly reviewed. Finally, a case study is described in detail: siloxane-nanoparticle dispersions are sprayed on sandstone and marble specimens. Using nanoparticles (NPs) in appropriate concentration, the deposited polysiloxane-nanoparticle composite coatings exhibit superhydrophobic and water-repellent properties. It is demonstrated that superhydrophobicity and water repellency can be (1) achieved using exclusively aqueous products, (2) achieved using inherent hydrophilic materials, and (3) accompanied by superoleophobicity and oil repellency. The effects of the coatings on the color, vapor permeability, and water absorption by capillarity of the treated sandstone and marble are discussed.

Moisture presence, salt precipitation and crystallization, temperature and ultraviolet radiation are main environmental factors of deterioration of the building materials of historic monuments. The presence of moisture in a material is due to rising and falling damp. Many commercial stone consolidation and water-repellent products contain tetraethoxysilane (TEOS). Synthesis of composite and nanocomposite coatings is an important method to improve the protective properties of these products. In this work composite coatings by adding silica nanoparticles to TEOS-based commercial products were synthesized. TEOS-based commercial products were RC-70 and RC-90. The type of silica nanoparticles used was Aerosil 200. As substrate dolomite marble specimens were used. The protective properties of the coatings were examined by water capillary absorption tests, salt spray tests and ultraviolet radiation tests. Coating characterization, the study of the morphologies of the surfaces and the investigation of the coatings behaviour in weathering conditions, was carried out by SEM, AFM, gravimetric measurements, optical observation and measurements of colour variation, contact angle and porosity. The protective properties of the coatings depended on the type of the polymeric material and the addition of silica nanoparticles. All coatings used protected marble against salt weathering and ultraviolet radiation. Polymeric coatings decreased porosity, surface roughness, water absorption, salt crystallization and the height of the capillary rise and increased contact angle values. Exposure in ultraviolet radiation conditions decreased in all cases contact angle values. Better protective properties were observed in the case of RC-90 in comparison to RC-70. This can be attributed to the increased elasticity of the structure of RC-90, due to the presence of the methylphenyl component. The addition of silica nanoparticles decreased porosity and improved the protective behaviour of the coatings against salt weathering and ultraviolet radiation.

Samples removed from stucco ornaments of two mosques (seventeenth century) in El-Mahalla El-Kubra, Delta, Egypt, are investigated using optical microscopy, micro-Raman and micro-FTIR spectroscopy and X-ray diffraction (XRD). Samples are studied as removed from the ornaments and after treatment with trichloromethane, which was used to extract the organic content. Moreover, the stratigraphies of the ornaments are investigated through a sample’s cross-section analysis revealing a bulk stucco layer, a colouring layer (either red or black) and overpainted layers of later interventions. Red and black colouring layers are composed mainly of fired brick enriched with hematite and carbon black, respectively. Shellac, found in high quantities, is the binding medium used in the colouring layers where small amounts of tree resins are detected as well. Bulk stucco is composed of gypsum and calcite. Metal soaps, oil and tree resins are also detected in the stucco layers. Other identifications are described in the report which, to the best of our knowledge, is the first effort to identify the materials contained in the “Delta style” stucco used in Ottoman buildings in Egypt.

Samples removed from funeral figurines, dated the third to the second century BC (Hellenistic period) and found in Macedonia, Greece, are investigated using high-performance liquid chromatography. Two results are reported that provide new insights into ancient polychromy. Firstly, high-performance liquid chromatography results, in combination with historical information, indicate that insect species of cochineal, most probably Porphyrophora hamelii Brandt, was used in Hellenistic objects. Secondly, madder detected in the archaeological samples contains high amounts of purpurin (alizarin is either not detected or detected in trace). This relative composition, which is recorded using the hydrochloric acid method for dyestuff extraction, is consistent with that prepared from wild madder (Rubia peregrina L.), which is a common plant in the Mediterranean region.

Fourier transform infrared spectroscopy and imaging coupled to optical microscopy, scanning electron microscopy coupled to energy dispersive x-ray spectroscopy and high-performance liquid chromatography (HPLC) coupled to diode-array detection are used to investigate two samples removed from a painted decoration of a burial kline and a textile fragment, both found in Koru tumulus (fifth century BCE) in Daskyleion. Tyrian purple and kaolinite were identified in both samples, thus suggesting that the aluminosilicate compound had an important role in the applied painting and dyeing processes. The textile fragment is composed of undyed cotton and silk yarns dyed with the molluskan dye. The relative compositions of the molluskan materials used in the two archaeological objects are similar and comparable with the corresponding composition measured for a purple sample originated from Murex trunculus mollusks according to the HPLC results. This result is supported by principal component analysis (PCA) which, furthermore, takes into account the relative compositions of the extracts of the three Mediterranean mollusks, published in previous reports.