Characterization and behaviour of ZnO-based nanocomposites designed for the control of biodeterioration of patrimonial stoneworks

Abstract

In this study, a preventive method for fighting bio-deterioration of stone substrates is proposed. This is\ud based on the use of bioactive zinc oxide nanoparticles (ZnO-NPs), which are able to exert a marked\ud biological activity over a long period of time due to their peculiar structure. ZnO-NPs are synthesised by\ud a simple and reproducible electrochemical procedure. The nanomaterials are embedded in consolidant/\ud water-repellent matrices to obtain nanostructured coatings. Commonly used products based on\ud tetraethoxysilane and/or polysiloxanes were tested. The resulting nanomaterials were fully characterised\ud by X-ray photoelectron spectroscopy (XPS) to investigate the amount and composition of the NPs and\ud the behaviour of the nanocomposites. Inductively coupled plasma mass spectrometry (ICP-MS) was\ud used for the study of the release of metal from the composites when put in contact with artificial\ud rainwater. The nanocomposites were applied to specimens composed of three different types of stone\ud and chromatic changes upon curing were measured by spectrophotocolorimetry. Finally, morphological\ud characterization by scanning electron microscopy (SEM) was performed. The bioactivity of ZnO-NPs\ud nanocomposites was also assessed in preliminary tests against Aspergillus niger fungu

Surface characterization of textiles modified by copper and zinc oxide nano‐antimicrobials

“…In this paper, we report on the impregnation of various textiles with copper and zinc oxide nanomaterials in order to confer them antimicrobial properties. CuNPs and ZnONPs have been electrosynthesized and characterized following previous protocols; here, they are specifically investigated in the textile context, and a detailed surface spectroscopic investigation is used to fully characterize the modification of the textile products upon NPs impregnation. CuNPs have been prepared by means of sacrificial anode technique in the presence of tetraoctylammonium chloride as stabilizing agent and are characterized by nanometer‐sized diameter and narrow size dispersion.…”

Development of a novel conservation treatment of stone monuments with bioactive nanocomposites

“…40 days in order to allow for complete drying of the surfaces, Silo111 and Estel1100 were applied two times by brush. These consolidant/water-repellents were used both as such and admixed with zinc oxide (0.4 % w/w) and copper (0.03 % w/w) nanoparticles, which were prepared by our research group [14,32].…”

“…Commonly used tetraethoxysilane (TEOS)-and/or siloxanes-based materials (Estel1000, Silo111, and Estel1100) have been selected and the resulting nanomaterials have been fully characterised with XPS in order to determine the amount and speciation of the NPs available on the surface. Moreover, preliminary data [32] obtained by inductively coupled plasma mass spectrometry have shown that zinc is released when the coating is put in contact with acidified water, simulating rain conditions.…”

“…The study aims to demonstrate that, in the case of ZnO-based composites, higher NPs loadings can be achieved without affecting the colour of the stone substrates: this is an important issue since the amount of bioactive species which is released by the composite (which is related, in turn, to the durability of the biocide activity) has been shown to depend on the initial concentration [14,32]. Preliminary laboratory tests were performed consisting in testing of the nanocoatings on different stone samples; evaluation of chromatic variations and morphological behaviour were carried out with colorimetry and SEM-EDS, respectively.…”

Gel Point Determination of TEOS-Based Polymeric Materials with Application on Conservation of Cultural Heritage Buildings

“…To provide the material with antimicrobial activity, here we propose the addition of ZnO nanoparticles [13,14] to the aforementioned polymeric formulation [12]. We select these nanoparticles due to their confirmed chemical stability, biocompatibility, and bioactivity [15] and to their limited use in materials for stone conservation. Moreover, these nanoparticles may also provide superhydrophobicity to the material [16], which is also highly desired for coatings used for stone protection.…”