Special Issue "Communications from TechnoHeritage 2017"

A special issue of Coatings (ISSN 2079-6412).

Deadline for manuscript submissions: closed (28 February 2018)

Special Issue Editors

Guest Editor
Prof. Dr. María J. Mosquera

Departamento de Química-Física, Facultad de Ciencias, University of Cadiz, 11510 Puerto Real, Cádiz, Spain
Website | E-Mail
Phone: +34-95-601-63-31
Interests: nanostructured materials; surfactant-synthesized materials; sol-gel route; hydrophobic and superhydrophobic coatings; photoactive coatings with self-cleaning properties; consolidant materials; application on building materials
Guest Editor
Prof. Dr. M.L. Almoraima Gil

Departamento de Química-Física, Facultad de Ciencias, University of Cadiz, 11510 Puerto Real, Cádiz, Spain
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Special Issue Information

Dear Colleagues,

The international conference TechoHeritage 2017 was held in Cadiz, Spain, 21-24 May, 2017. More of 200 communication, with high scientific value, from 23 different countries, were presented. A Special Issue of selected papers from TechnoHeritage 2017 will be published in Coatings. Submissions relating to any of the following topics are welcomed:

  • Cleaning products and processes;
  • Consolidants;
  • Hydrophobic and Superhydrophobic products;
  • Self-cleaning and Anti-graffiti agents;
  • Biocides and bioreceptivity processes;
  • Depollutant products.
Prof. Dr. María J. Mosquera
Prof. Dr. M.L. Almoraima Gil
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All papers will be peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Coatings is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Published Papers (8 papers)

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Research

Open AccessFeature PaperArticle A Study on the Suitability of Mechanical Soft-Abrasive Blasting Methods to Extract Graffiti Paints on Ornamental Stones
Coatings 2018, 8(10), 335; https://doi.org/10.3390/coatings8100335
Received: 9 September 2018 / Revised: 17 September 2018 / Accepted: 19 September 2018 / Published: 24 September 2018
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Abstract
Mechanical methods to extract undesired graffiti paints on ornamental stones are efficient cleaning methods from an economical point of view. However, effort on the optimization of mechanical cleaning procedures to avoid any damage to the substrate is required for large areas. In this [...] Read more.
Mechanical methods to extract undesired graffiti paints on ornamental stones are efficient cleaning methods from an economical point of view. However, effort on the optimization of mechanical cleaning procedures to avoid any damage to the substrate is required for large areas. In this study, two ornamental stones with different composition and texture, and which are commonly used in Spain and Portugal were selected: Granite Vilachán and Limestone Lioz. Moreover, the most common surface finishes were selected-disc-cutting and bush-hammering to simulate the stones found in buildings. Two graffiti spray paints were selected: Blue Ultramarine and Silver Chrome. As cleaning methods, three soft-abrasive blasting procedures: Hydrogommage (mixture of air–water–micro grained silicon abrasive), IBIX (mixture of air–micro grained silicon abrasive), and dry-ice procedure (carbon dioxide ice pellets), were tested at pressure below 0.4 MPa. The methodology for evaluating the effectiveness and harmfulness of each cleaning method was based on stereomicroscopy, scanning electron microscopy, color spectrophotometry, and confocal microscopy. As result, IBIX achieved the highest level of graffiti paint extraction although this method increased the surface roughness. Conversely, cleaning based on dry-ice projection did not achieve a satisfactory extraction of the graffiti, mainly of the blue paint. Dry-ice blasting can induce acid environments and IBIX causes dust emission during the projection. Hydrogommage was the most efficient cleaning method amongst the tested procedures, because it induced the lowest roughness change and although the graffiti extraction was not complete, it achieved the highest removal level. Therefore, the most satisfactory cleaning method was that achieving a satisfactory extraction level, minimal modifications of the surface roughness, an economic suitability, an environmental integration, and lower human health risks. Full article
(This article belongs to the Special Issue Communications from TechnoHeritage 2017)
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Open AccessFeature PaperArticle Photocatalytic Activity of TiO2/AuNRs–SiO2 Nanocomposites Applied to Building Materials
Coatings 2018, 8(9), 296; https://doi.org/10.3390/coatings8090296
Received: 4 July 2018 / Revised: 10 August 2018 / Accepted: 17 August 2018 / Published: 22 August 2018
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Abstract
In this work, the self-cleaning and photocatalytic properties of mesoporous TiO2/AuNRs-SiO2 composites (namely UCA–TiO2Au) prepared by a simple and low-cost technique were investigated toward application in building materials. Mesoporous photocatalytic nanocomposites coating the surface of stone and other [...] Read more.
In this work, the self-cleaning and photocatalytic properties of mesoporous TiO2/AuNRs-SiO2 composites (namely UCA–TiO2Au) prepared by a simple and low-cost technique were investigated toward application in building materials. Mesoporous photocatalytic nanocomposites coating the surface of stone and other building materials are a very promising approach to address relevant questions connected with the increasing atmospheric pollution. We tested three types of preformed TiO2/AuNRs nanostructures in order to evaluate the effect of AuNRs on the photocatalytic activity of resulting coatings deposited on the surface of a popular building limestone. The resulting nanocomposites provide crack-free surface coatings on limestone, effective adhesion, improve the stone mechanical properties and impart hydrophobic and self-cleaning properties. Photocatalytic characterization involved the degradation of a target compound (Methylene blue; MB) under direct exposure to simulated solar light using TiO2 P25 Evonik (TiO2 P25) as a reference material. Moreover, these coatings upon irradiation by simulated solar light were successfully employed for the photocatalytic oxidation of carbon soot. The experimental results revealed that UCA–TiO2Au samples are the best performing coating in both MB bleaching and soot degradation. Full article
(This article belongs to the Special Issue Communications from TechnoHeritage 2017)
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Open AccessFeature PaperArticle New Consolidant-Hydrophobic Treatment by Combining SiO2 Composite and Fluorinated Alkoxysilane: Application on Decayed Biocalcareous Stone from an 18th Century Cathedral
Coatings 2018, 8(5), 170; https://doi.org/10.3390/coatings8050170
Received: 8 March 2018 / Revised: 30 April 2018 / Accepted: 1 May 2018 / Published: 2 May 2018
Cited by 3 | PDF Full-text (3597 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
An effective procedure has been developed to consolidate and hydrophobize decayed monumental stones by a simple sol-gel process. The sol contains silica oligomer, silica nanoparticles and a surfactant, preventing gel cracking. The effectiveness of the process on biocalcareous stone samples from an 18th [...] Read more.
An effective procedure has been developed to consolidate and hydrophobize decayed monumental stones by a simple sol-gel process. The sol contains silica oligomer, silica nanoparticles and a surfactant, preventing gel cracking. The effectiveness of the process on biocalcareous stone samples from an 18th century cathedral has been evaluated, and it was found that the gel creates effective linking bridges between mineral grains of the stone. Silica nanoparticles produced a significant increase in the mechanical resistance and cohesion of the stone. The application of an additional fluorinated oligomer onto the consolidated stone gave rise to a surface with lasting hydrophobicity, preventing water absorption. Full article
(This article belongs to the Special Issue Communications from TechnoHeritage 2017)
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Open AccessFeature PaperArticle Lanthanum-Silica Sol-Gel Coatings for Protecting Metallic Materials in Museums: Approaches to Copper, Bronze, Lead and Steel
Coatings 2018, 8(4), 138; https://doi.org/10.3390/coatings8040138
Received: 9 February 2018 / Revised: 9 April 2018 / Accepted: 10 April 2018 / Published: 12 April 2018
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Abstract
Museum objects made from metals face the challenge of delaying corrosion in exhibition rooms, showcases and holdings. This study examined some innovative solutions used to protect such items based on sol-gel coatings doped with lanthanum. These coatings were prepared from sols based on [...] Read more.
Museum objects made from metals face the challenge of delaying corrosion in exhibition rooms, showcases and holdings. This study examined some innovative solutions used to protect such items based on sol-gel coatings doped with lanthanum. These coatings were prepared from sols based on TEOS as a precursor. Lanthanum acetate/nitrate was added as a doping agent and corrosion inhibitor. The coatings were deposited upon slabs of copper, bronze, lead and steel, since they are among the most common metals present in museums items. The coatings application was accomplished by immersion-extraction, and the remaining sols were gelled and characterized by Fourier transformed infrared spectroscopy and differential thermal analysis and thermogravimetry. To evaluate the behaviour and resistance of the coatings, tests of accelerated aging were carried out in climatic and Kesternich chambers, as well as under an atmosphere saturated with organic acids and under UV irradiation. The simulated conditions tested were undertaken to approach real conditions inside a conventional museum showcase. The microstructure of the coatings before and after accelerated aging tests was observed through optical and field emission scanning electron microscopies. The results indicated that these coatings can be a useful preventive, conservation avenue to protect copper, bronze and lead items exhibited in museums. Full article
(This article belongs to the Special Issue Communications from TechnoHeritage 2017)
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Open AccessArticle Laser-Assisted Removal of Graffiti from Granite: Advantages of the Simultaneous Use of Two Wavelengths
Coatings 2018, 8(4), 124; https://doi.org/10.3390/coatings8040124
Received: 27 February 2018 / Revised: 21 March 2018 / Accepted: 25 March 2018 / Published: 28 March 2018
Cited by 1 | PDF Full-text (8791 KB) | HTML Full-text | XML Full-text
Abstract
Currently, removal of graffiti from stone monuments is a particularly challenging task. Lasers, being highly controllable and precise tools with minimal chemical waste, offer a key solution in this respect and a significant amount of research has been dedicated to this subject. Studies [...] Read more.
Currently, removal of graffiti from stone monuments is a particularly challenging task. Lasers, being highly controllable and precise tools with minimal chemical waste, offer a key solution in this respect and a significant amount of research has been dedicated to this subject. Studies related to the laser cleaning of carbonate stones (such as limestone and marble) reported the extraction of the graffiti layer, although minimal damage to the substrate can be also detected. Recently, research efforts have been focused on the cleaning of granite, which is a complex stone due to its grained and polymineralic texture. Tests involving different wavelengths indicated that the effectiveness of the cleaning procedure is highly dependent on two components: The composition of the binding medium of the graffiti and the fissure system of the granite. In that direction, the aim of this paper is to investigate and to compare the cleaning effectiveness of two wavelengths emitted from a nanosecond (ns) Q-Switched Nd:YAG laser system (IR at 1064 nm and UV at 355 nm), as well as their simultaneous application at different energy density ratios FIR/FUV. The effectiveness of this combined methodology has been shown in several other cases; i.e., for the removal of pollution crusts from carbonate stones (marble). For this study, three different in composition graffiti paints (blue, black, and silver) were applied on a fine-grained granite originating from the NW Iberian Peninsula. Prior to the irradiation tests, the damage thresholds of the granite, as well as the extraction thresholds of the graffiti, were determined. Then, several tests involving a variety of parameters (fluence value, number of pulses, etc.) were performed and the most satisfactory irradiation conditions from each individual wavelength as well as their combination were compared, based on graffiti extraction level and any damage induced on the granite forming minerals. The analytical techniques used for the evaluation were stereomicroscopy, color measurements in CIELAB and CIELCH color spaces, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and confocal microscopy. The experiments indicated the superiority of the combined laser cleaning regarding blue and black graffiti extraction. Full article
(This article belongs to the Special Issue Communications from TechnoHeritage 2017)
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Open AccessArticle Production of Antagonistic Compounds by Bacillus sp. with Antifungal Activity against Heritage Contaminating Fungi
Coatings 2018, 8(4), 123; https://doi.org/10.3390/coatings8040123
Received: 15 February 2018 / Revised: 15 March 2018 / Accepted: 21 March 2018 / Published: 28 March 2018
Cited by 1 | PDF Full-text (9187 KB) | HTML Full-text | XML Full-text
Abstract
In recent years, the population has become acutely aware of the need to conserve the world’s resources. The study of new compounds produced by natural means is important in the search for alternative green solutions that act against biodeteriogenic fungi, which promote biodeterioration [...] Read more.
In recent years, the population has become acutely aware of the need to conserve the world’s resources. The study of new compounds produced by natural means is important in the search for alternative green solutions that act against biodeteriogenic fungi, which promote biodeterioration of built cultural heritage sites. The present paper reports new solutions, derived from Bacillus sp. CCLBH 1053 cultures, to produce lipopeptides (LPP) that can act as green biocides to promote the safeguarding of stone artwork. In the stationary phases of bacteria growth, peptone supplementation and sub-lethal heat activation improve the second cycle of sporulation, greatly enhancing LPP production. The bioactive compounds produced by Bacillus cultures suppress biodeteriogenic fungi growth on stone materials, and, hence, provide an important contribution to the development of new biocides for cultural heritage rehabilitation. Full article
(This article belongs to the Special Issue Communications from TechnoHeritage 2017)
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Open AccessArticle The Use of a Saturated Long Carbon Chain Sodium Monocarboxylate for the Corrosion Inhibition of Lead Objects in Atmospheric Conditions and in Acetic Acid Corrosive Solutions
Coatings 2018, 8(4), 118; https://doi.org/10.3390/coatings8040118
Received: 8 January 2018 / Revised: 15 March 2018 / Accepted: 18 March 2018 / Published: 23 March 2018
Cited by 1 | PDF Full-text (3183 KB) | HTML Full-text | XML Full-text
Abstract
In this paper, a saturated long carbon chain sodium monocarboxylate containing 18 carbons—labeled NaC18—was used for the formation of a lead carboxylate coating to inhibit the corrosion of lead in atmospheric conditions and in acetic acid corrosive solutions. The effect of [...] Read more.
In this paper, a saturated long carbon chain sodium monocarboxylate containing 18 carbons—labeled NaC18—was used for the formation of a lead carboxylate coating to inhibit the corrosion of lead in atmospheric conditions and in acetic acid corrosive solutions. The effect of stirring of the coating solution during the coating process on the inhibition efficiency was studied. The coating was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy which have confirmed a formation of lead carboxylate layer on the lead metal surface. The corrosion inhibition properties of the coating were tested using linear sweep voltammetry and electrochemical impedance spectroscopy in a solution simulating the atmospheric conditions and in an acetic acid corrosive solution. Results show that the lead carboxylate forms a protective barrier that inhibits corrosion of lead in atmospheric conditions and in acetic acid corrosive solutions. Full article
(This article belongs to the Special Issue Communications from TechnoHeritage 2017)
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Open AccessArticle Study of Calcium Ethoxide as a New Product for Conservation of Historical Limestone
Coatings 2018, 8(3), 103; https://doi.org/10.3390/coatings8030103
Received: 20 February 2018 / Revised: 7 March 2018 / Accepted: 12 March 2018 / Published: 13 March 2018
Cited by 3 | PDF Full-text (12671 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
The combination of multiple physical, chemical and biological factors causes the weathering of limestone used in the field of cultural heritage. To overcome the limitations of traditional consolidating products and to meet the requirements of the historical building substrates, during the European collaborative [...] Read more.
The combination of multiple physical, chemical and biological factors causes the weathering of limestone used in the field of cultural heritage. To overcome the limitations of traditional consolidating products and to meet the requirements of the historical building substrates, during the European collaborative project NANOMATCH, alkaline earth alkoxides were developed and studied as consolidating agents for limestone. Among these new products, calcium ethoxide, with the formula Ca(OEt)2, was chosen for this study and investigated in depth as an alternative consolidating treatment. It was first characterized through a study of the carbonation process: its kinetics, reaction pathway and the evaluation of formed mineralogical phases. Subsequently, it was applied on limestones with different total open porosity to test its performance as a consolidating agent. The compatibility and the efficiency of the treatment were investigated with a multi-technique approach and compared with results obtained with a reference product, based on nanolime. This study indicates that calcium ethoxide shows better results with respect to the reference product, both in terms of compatibility and consolidation effect. Full article
(This article belongs to the Special Issue Communications from TechnoHeritage 2017)
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