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This is the book of abstracts created for the goINDIGO 2022 international graffiti symposium organised in the framework of the academic project INDIGO.

Aim of the present work is the preparation of organic membranes with narrow pore size distribution and high porosity to be applied in the field of microfluidic analyses and as selective gates in microchip-based technologies for separation, detection and dosing of molecular or ionic species, charged nanoparticles or biomolecules. Highly selective membranes with controlled porosity can be obtained by coating appropriate supports with nanoporous thin films. The capability of block copolymers to spontaneously arrange into well-defined ordered structures with nanoscopic size has proven to be particularly advantageous for templating nanoporous membranes and recently block copolymer-derived membranes have been proposed as highly selective layers in composite membranes. The main advantages of block copolymer-templated membranes over other types of polymer membranes are their narrow pore size distribution, high void fraction and smooth surfaces, resulting in superior selectivity, high fluxes and fouling resistance. Pore size can be easily varied to optimize size selectivity, and additional separation mechanisms can be introduced by tuning the membrane surface properties through functionalization of the pore walls. In this contribution, we describe the fabrication procedure of nanoporous membranes with uniform pore size and high pore density obtained by spin-coating polystyrene-block-poly(ethylene-oxide) (PS-b-PEO) solutions on commercial silicon nitride microsieves (5μm of pores diameters). To better control the formation of well-defined nanostructures, a supramolecular approach was applied, based on the complexation by hydrogen-bonding of the PEO block with small molecules bearing hydroxyl groups, i.e. resorcinol. The addition of resorcinol in different PEO/resorcinol ratios was investigated and the effect on the alignment of PEO domains (and consequently on the final porosity) was confirmed. From PS-b-PEO/resorcinol mixtures, ordered films with normally oriented PEO/resorcinol cylindrical domains were obtained. These nanostructured films were subjected to a previous UV treatment, to improve their mechanical properties by crosslinking the PS matrix, and then to a selective wet treatement with iso-propanol, to remove resorcinol and create an hydrophilic porous system in the PEO domains. Composite membranes consisting of large-pore silicon nitride support and a continuous polymeric nanoporous layer were fabricated and tested as gates for controlled transport of chemicals.

Un approccio supramolecolare per la fabbricazione di membrane polimeriche nano e isoporose a base di copolimeri a blocchi.

Highly selective membranes with controlled porosity can be obtained by growing thin films of mesoporous oxides on an appropriate support. This can be achieved employing organic/inorganic mixed micellar solutions based on the use of commercial or ad hoc designed templates. Amphiphilic block copolymers are very attractive materials as soft-templating agents. When mixed with organic solvents selective for one of the blocks, they can self-assemble into micelles with the insoluble blocks constituting the micellar core and the soluble ones the corona. The morphology and size of self-assembled micelles depend on the size (length) and nature (polarity) of the blocks, and on solution parameters. Silica porous membranes described in this contribution were obtained by sol-gel reaction of a silicon oxide precursor (TEOS) and using polystyrene-block-poly(ethylene-oxide) (PS-b-PEO) block copolymers as templates. In order to modulate pore sizes and alignment of the final material, many different variables were changed: e.g. block copolymer chain length, block copolymer/TEOS ratio, type of solvents, solvent ratio and use of additives (i.e. polystyrene homopolymer). Aim of the present work is the preparation of silica membranes with narrow pore size distribution and high porosity to be applied in the field of microfluidic analyses and as selective gates in microchip-based technologies for separation, detection and dosing of molecular or ionic species, charged nanoparticles or biomolecules.

MICROFLUIDIC DEVICE: DEVELOPMENT AND TESTING OF NANOSTRUCTURED OXIDIC MATERIALS

Highly selective silica membranes with controlled porosity can be obtained by employing organic/inorganic mixed micellar solutions based on the use of commercial templates. Amphiphilic block copolymers are very attractive materials as structure directing agents. When mixed with organic solvents selective for one of the blocks, they can self-assemble into micelles with the insoluble blocks constituting the micellar core. The morphology and size of self-assembled micelles depend on the size (length) and nature (polarity) of the templates blocks, and on solution parameters. Silica porous films described in this contribution are obtained by sol-gel reaction of tetraethyl orthosilicate (TEOS) using polystyrene-block-poly(ethylene-oxide) (PS-b-PEO) copolymers as templates. In order to modulate pore sizes and alignment in the final material, many different variables are changed: e.g., block copolymer chain length, block copolymer/TEOS ratio, solvents, hydrophilic/hydrophobic solvent ratio and use of additives (i.e. polystyrene homopolymer). To obtain an oxidic mesoporous membrane, the block copolymer/TEOS micellar solution is deposited on inorganic supports via spin-coating. The spin coating conditions used ensure fast evaporation of solvents, freezing in the solid state the micelles shape present in solution. Block copolymer micelles are finally removed by thermal degradation in air, leaving an amorphous porous material which can be applied in the field of microfluidics for separation, detection and dosing of molecules, ions, charged nanoparticles or biomolecules.

Highly selective membranes with controlled morphology can be obtained by growing thin mesoporous oxide films on an appropriate support. This can be achieved employing organic/inorganic mixed micellar solutions based on the use of proper templates. Amphiphilic block copolymers are very attractive materials for soft-templating. When mixed with organic solvents selective for one of the blocks, they can self-assembly into micelles with the insoluble blocks constituting the micellar core and the soluble ones the corona. The silica porous membranes described in this contribution were obtained by sol-gel reaction of a silicon oxide precursor (TEOS) and using polystyrene-block-poly(ethylene-oxide) (PS-b-PEO) copolymers as templates. Morphology and size of the self-assembled micelles and of the final porous oxide depend both on composition parameters (such as the length and nature of the polymer blocks) and on solution parameters (such as the hydrophilic/hydrophobic balance between solvents and cosolvents). This contribution focuses on the effect of composition parameters, namely the chain length of each polymer block, the stoichiometric ratio of the monomers, and the polymer/silica ratio. By changing these parameters silica structures with narrow pore size distribution and pore shapes ranging from spheres to channels were obtained. The final goal of this research will be the preparation of silica membranes with controlled and high porosity to be applied in the field of microfluidic analyses (e.g. Lab-on-a-chip devices) and as selective gates in microchip-based technologies for separation, detection and dosing of molecular or ionic species, charged nanoparticles and biomolecules.

The effectiveness of Agar gels for copper stain removal from marble surfaces was systematically studied. Gels with different agar concentrations (1, 3, 5%) and different chelating agents used as additives (ethylenediaminetetraacetic acid, EDTA, and ammonium citrate tribasic, TAC) were tested on laboratory marble specimens for different contact times (30 and 60 min). For better characterization, hydrogels were lyophilised and cryogels were obtained. Systematic comparison of different formulations was feasible on cryogels and performed in terms of: (i) the morphological properties, by field-emission scanning electron microscopy (FE-SEM); (ii) the type of Cu(II)-complexes formed and their quantitative comparison by electron paramagnetic resonance (EPR) spectroscopy; (iii) the total amount of copper removed from marble surfaces, by Inductively Coupled Plasma–Optical Emission Spectrometry (ICP-OES). AgarArt 1% with TAC exhibited the highest effectiveness for copper stain removal after 60 min contact (431 μg/cm2). Such a good cleaning effectiveness can be ascribed to the co-presence of the following properties: efficient metal coordination, which is related to the additive presence, and favourable gel morphology, related both to the gel concentration and to the additive type. In fact, it was observed that both the low gel concentration and the presence of TAC are related to a narrow pore size distribution in gels, besides the possibility of copper coordination. The presence of EDTA results in a broader pore size distribution and in a lower gel strength, with respect to gels with TAC. Thus, a new procedure for studying gels was proposed, which allows to optimize the conditions for metal stain removal from built heritage.

Cleaning an artwork is an extremely delicate and irreversible procedure in a conservation work. Art conservators constantly work to identify an appropriate and correct cleaning methods according to the requirements of different substrates and in order to solve different removal problems. In recent years, gels positively responded to the conservation requests becoming a valid help and, in several cases, the best alternative compared to traditional cleaning methods. This paper proposes a summary of the most recent results regarding agar gels and their applications in cleaning art surfaces; moreover, specific applications of agar gels formulated on purpose to address different conservation problems are also discussed. (C) 2020 Elsevier Masson SAS. All rights reserved.

Copper complexes with different ligands (ethylenediaminetetraacetic acid, EDTA, ammonium citrate tribasic, TAC, and alanine, ALA) were studied in aqueous solutions and hydrogels with the aim of setting the optimal conditions for copper stain removal from marble by agar gels, with damage minimization. The stoichiometry and stability of copper complexes were monitored by ultraviolet-visible (UV-Vis) spectroscopy and the symmetry of Cu(II) centers in the different gel formulations was studied by electron paramagnetic resonance (EPR) spectroscopy. Cleaning effectiveness in optimized conditions was verified on marble laboratory specimens through color variations and by determining copper on gels by inductively coupled plasma-mass spectrometry (ICP-MS). Two copper complexes with TAC were identified, one having the known stoichiometry 1:1, and the other 1:2, Cu(TAC)2, never observed before. The stability of all the complexes at different pH was observed to increase with pH. At pH 10.0, the gel’s effectiveness in removing copper salts from marble was the highest in the presence of ALA, followed by EDTA, TAC, and pure agar gel. Limited damage to the marble surface was observed when gels with added EDTA and TAC were employed, whereas agar gel with ALA was determined to be the most efficient and safe cleaning material.

The Lab4treat experience has been developed to demonstrate the use of magnetic materials in environmental applications. It was projected in the frame of the European project Mat4Treat, and it was tested several times in front of different audiences ranging from school students to the general public in training and/or divulgation events. The experience lends itself to discuss several aspects of actuality, physics and chemistry, which can be explained by modulating the discussion depth level, in order to meet the interests of younger or more experienced people and expand their knowledge. The topic is relevant, dealing with the recycling of urban waste and water depollution. The paper is placed within the field of water treatment for contaminant removal, therefore, a rich collection of recent (and less recent) papers dealing with magnetic materials and environmental issues is described in the Introduction section. In addition, the paper contains a detailed description of the experiment and a list of the possible topics which can be developed during the activity. The experimental approach makes the comprehension of scientific phenomena effective, and, from this perspective, the paper can be considered to be an example of interactive teaching.

Multi-analytical chemical approaches are nowadays considered an important source of complementary information in archaeological functional studies. Here we report the results of an investigation carried out by means of liquid chromatography-mass-spectrometry (LC-MS), pyrolysis-gas chromatography-mass spectrometry (py-GC-MS) and Raman micro-spectroscopy (μRaman) applied onto residues sampled from ceramic vessels, found in the ancient cities of Assiut (Egypt, Middle Kingdom). These items, characterized by the typical conical shape of Kohl containers, represented an extraordinary opportunity to study, at the same time, well preserved archaeological records and the related contents. Thanks to the combined analysis, it was possible to hypothesize the original recipes adopted to prepare the ancient cosmetic. The profile of the fatty ingredients resulted congruent with the information collected by the archaeologist from the excavation site, regarding the culture and the ancient Egyptian practice of eye-painting. The analysis of the sedimentary material confirmed the provenance of the archaeological record

Agar is an interesting and versatile biopolymer capable of forming hydrogels useful in different applications. In particular, in the field of Cultural Heritage agar gels are often used as tools for cleaning the surfaces of artifacts. Agar gels are thermoreversible, peelable materials, exhibiting high retention of water and an intrinsic cleaning capability that can be increased and modulated by loading different cleaning agents. Agar gels are able to solubilize and retain dirt, and allow a confined release of the liquid phase, which is especially important when they are applied on water sensitive substrates. A detailed knowledge of the role of water in agar gels and of water/agar interactions is important to fully understand the properties and performances of agar gels as cleaning materials. Here we report the results of a systematic study aimed at exploring the water state and the types of water (i.e. bound non-freezable, bound freezable and freezable bulk-like) in agar hydrogels prepared from four different types of commercial agar powders. The influence of agar concentration on the water behaviour in the hydrogels was also investigated. The total water content, the identification and quantification of the different types of water was carried out by gravimetric, thermogravimetric and calorimetric analyses, while water mobility and localization in the gel network were investigated by unilateral H-1 NMR. Moreover, H-1 NMR depth profiles of agar gels applied on Noto stone specimens were collected to monitor the gel deformation due to water release and to evaluate the ability of the gel in controlling the water release into a porous material. (C) 2018 Elsevier B.V. All rights reserved.

Thermoresponsive poly(N-isopropylacrylamide)-grafted silica nanoparticles (SiNPs) have been synthesized and fully characterized by ATR-FTIR, TGA, HRTEM, BET and DLS analysis. Hybrid solid phase extraction (SPE) beds with tuneable pore size and switchable surface chemistry were prepared by packing the polymer-grafted nanoparticles inside SPE cartridges. The cartridges were tested by checking the thermo-regulated elution of model compounds, namely methylene blue, caffeine and amoxicillin. Extraction of the analytes and regeneration of the interaction sites on the sorbent surface was carried out entirely in water solution by changing the external temperature below and above the lower critical solution temperature (LCST) of the polymer. The results demonstrate that the elution of model compounds depends on the temperature-regulated size of the inter-particle voids and on the change of surface properties of the PNIPAM-grafted nanoparticles from hydrophilic to hydrophobic.