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Papers by rosa ponterio

Applied Sciences

The archaeometric study of the frescoes by the painter Saturnino Gatti (1463–1518) in the apse of... more The archaeometric study of the frescoes by the painter Saturnino Gatti (1463–1518) in the apse of the Church of San Panfilo in Villagrande di Tornimparte (L’Aquila) was the subject of the II National Research Project [...]

Applied Sciences

This paper reports the investigation of six microsamples collected from the vault of the San Panf... more This paper reports the investigation of six microsamples collected from the vault of the San Panfilo Church in Tornimparte (AQ). The aim was to detect the composition of the pigments and protective/varnishes, and to investigate the executive technique, the conservation state, and the evidence of the restoration works carried out in the past. Six microsamples were analyzed by optical microscopy, scanning electron microscopy coupled with energy-dispersive spectroscopy (EDS), X-ray fluorescence (XRF), and infrared and Raman spectroscopy. The investigations were carried out within the framework of the Tornimparte project “Archeometric investigation of the pictorial cycle of Saturnino Gatti in Tornimparte (AQ, Italy)” sponsored in 2021 by the Italian Association of Archeometry (AIAr).

Proceedings of the 2022 IMEKO TC4 International Conference on Metrology for Archaeology and Cultural Heritage

The Roman thermae in Reggio Calabria (Italy) provides many information regarding both engineering... more The Roman thermae in Reggio Calabria (Italy) provides many information regarding both engineering and technology for this type of buildings. A small treasure of three survived mural paintings encloses information about the artistic style and the ancient luxury of the baths. In order to get light on the executive technique and conservation state we performed the investigation of these paintings by following a non-invasive approach composed of multispectral imaging and spectroscopic analysis. By so doing, we determined the pigment palette and the distribution of some pigments allowing us to make some hypothesis about the executive technique and to provide a basis for a future virtual restoration of the paintings.

Materials Letters

The Neolithic painted pottery, spread all over southern Italy, is considered as an important chro... more The Neolithic painted pottery, spread all over southern Italy, is considered as an important chronological indicator for the development of VI-V millennium BC prehistoric settlements and cultural traditions. The goal of this work is to contribute to the study of this ceramic class through the chemical characterization of some samples coming from the Aeolian Islands. 16 different sherds have been selected and the pigments preserved in their decorations analyzed via non-invasive techniques: Fiber Optical Reflectance Spectroscopy (FORS), X-ray Fluorescence (XRF), Raman Spectroscopy and Infrared Spectroscopy (FT-IR). The different pigments, some of which no longer clearly visible to the naked eye (red ochre and raw umber) were identified, while the FT-IR data provided information about the pottery differentiation.

Virtual Archaeology Review

The new tools for 3D survey and modelling (as portable scanners and software packages), often in ... more The new tools for 3D survey and modelling (as portable scanners and software packages), often in combination with diagnostics, are nowadays able to provide indispensable elements for the study of archaeological artefacts; their applications to museum’s heritage can be also useful to integrate the traditional graphic documentation and contribute to enhancement and dissemination. This paper shows the benefit of using the aforementioned tools to study the peculiar clay mask No. 11114-E, discovered in 1973 in the Greek necropolis of Lipára, inside tomb No. 1558. The specimen, now exhibited in the Classical Section of the Aeolian Museum, is considered unique both in the Aeolian Islands and in the ancient Greek world, as it is the only one merging two half faces attributable to different characters. This feature, unknown at the time of discovery, has been highlighted in 2018, thanks to a restoration intervention by which a hard concretion layer covering a large portion of the mask surface...

Applied Sciences, 2022

Arsenic is a well-known contaminant present in different environmental compartments and in human ... more Arsenic is a well-known contaminant present in different environmental compartments and in human organs and tissues. Inorganic As(III) represents one of the most dangerous arsenic forms. Its toxicity is attributed to its great affinity with the thiol groups of proteins. Considering the simultaneous presence in all environmental compartments of other common functional groups, we here present a study aimed at evaluating their contribution to the As(III) complexation. As(III) interactions with four (from di- to hexa-) carboxylic acids, five (from mono- to penta-) amines, and four amino acids were evaluated via experimental methods and, in simplified systems, also by quantum-mechanical calculations. Data were analyzed also with respect to those previously reported for mixed thiol-carboxylic ligands to evaluate the contribution of each functional group (-SH, -COOH, and -NH2) toward the As(III) complexation. Formation constants of As(III) complex species were experimentally determined, an...

Remote Sensing, 2022

Cultural places represent the tangible part of the identity and historical heritage of a civiliza... more Cultural places represent the tangible part of the identity and historical heritage of a civilization as well as an extraordinary driving force for the economic development of a country. Within its huge asset, Italy counts a wide number of archaeological sites and monuments which, despite their cultural value, are totally cut off from the most important cultural routes. This paper aims to demonstrate how specific actions of digitization can contribute to valorize (restoring a cultural value) ‘marginal’ landmarks, promoting their knowledge and inclusion. The case study described is represented by the Church of “Santa Maria delle Palate”, located inside the well-known Archaeological Park of Halaesa Arconidea (Tusa, ME). The church, built in 1551 and subject to several renovations throughout the centuries, has been investigated as part of an interdisciplinary training and skill transfer project carried out by a CNR-IPCF research team. During the activities, the group of trainees approa...

Liquids, 2022

An experimental and computational study on the hydrolysis of Al3+ in aqueous solutions is here re... more An experimental and computational study on the hydrolysis of Al3+ in aqueous solutions is here reported. Speciation model and formation constants were determined by potentiometric titrations at T = 298.15 K, 0.1 ≤ I/mol L−1 ≤ 1 in aqueous NaCl, NaNO3, NaCl/NaNO3 solutions. The dependence of formation constants on ionic strength is reported in all the ionic media over the range of 0.1–1.0 mol L−1. Under the studied experimental conditions, the formation of Al3(OH)45+ and Al13(OH)327+ species is observed in all the investigated ionic media and ionic strengths. The formation constants of the species formed by Al3+ with Cl− were determined together with the dependence on the ionic strength. Moreover, with the aim of unveiling the molecular structure of the formed Al complexes, quantum-mechanical calculations and state-of-the-art ab initio molecular dynamics simulations under explicit solvation were executed. These computations show, for the first time, the highly cooperative role played...

Molecules, 2021

Spectral preprocessing data and chemometric tools are analytical methods widely applied in severa... more Spectral preprocessing data and chemometric tools are analytical methods widely applied in several scientific contexts i.e., in archaeometric applications. A systematic classification of natural powdered pigments of organic and inorganic nature through Principal Component Analysis with a multi-instruments spectroscopic study is presented here. The methodology allows the access to elementary and molecular unique benchmarks to guide and speed up the identification of an unknown pigment and its recipe. This study is conducted on a set of 48 powdered pigments and tested on a real-case sample from the wall painting in S. Maria Delle Palate di Tusa (Messina, Italy). Four spectroscopic techniques (X-ray Fluorescence, Raman, Attenuated Total Reflectance and Total Reflectance Infrared Spectroscopies) and six different spectrometers are tested to evaluate the impact of different setups. The novelty of the work is to use a systematic approach on this initial dataset using the entire spectrosco...

Many-body Approaches at Different Scales, 2018

In this note we revisit the Kovacs effect, concerning the way in which the volume of a glass-form... more In this note we revisit the Kovacs effect, concerning the way in which the volume of a glass-forming liquid, which has been driven out of equilibrium, changes with time while the system evolves towards a metastable state. The theoretical explanation of this phenomenon has attracted much interest even in recent years, because of its relation with some subtle aspects of the still elusive nature of the glass transition. In fact, even if there is a rather general consensus on the fact that what is experimentally observed on cooling is the dramatic effect produced by the dynamical arrest of slower degrees of freedom over the experimental time scale, it is not yet clear whether this phenomenology can be justified upon assuming the existence of an underlying (possibly, high order) phase transition at lower temperatures. liquids liquids!supercooled supercooled liquids Kovacs effect ortho-terphenyl

Journal of Analytical Atomic Spectrometry, 2017

This work presents the first neutron characterization of artefacts from the grave-goods of Kha an... more This work presents the first neutron characterization of artefacts from the grave-goods of Kha and Merit, a unique cultural treasure of mankind and preserved at the Museo Egizio in Turin.

AIP Conference Proceedings, 2000

This paper describes the importance of watermarks reproduction, in particular the advantages and ... more This paper describes the importance of watermarks reproduction, in particular the advantages and potentiality of beta-ray technique's application to this aim is emphasized. The method involved a radioactive carbon sheet which emits radiation that images a photographic film. After a conventional processing the film produces an exact copy of the watermark. Techniques which give similar results are also considered. .

Annali di chimica

This paper presents the results of a study that is part of a wider research program regarding the... more This paper presents the results of a study that is part of a wider research program regarding the knowledge of the initial living phases of Sicilian agricultural and pastoral societies. Three ceramic samples attributed to the medium initial Neolithic (NEO1 and NEO2) and to the first neolithic (NEO3), recovered in two different archaeological sites of the western Sicily, have been analysed. Chemical, mineralogical and spectroscopic data point out a similarity between NEO1 and NEO3 samples; compositional and morphological differences instead have been observed in the NEO2 sample. The firing temperatures of the samples have been estimated by Mössbauer spectroscopy; they are lower than 500 degrees C for the samples NEO1 and NEO3, and about 700 degrees C for NEO2.

Polymer, 2005

The reaction of the epoxy derivatives 2-(3, 4-epoxycyclohexyl) ethyl-trimethoxysilane (ECET) and ... more The reaction of the epoxy derivatives 2-(3, 4-epoxycyclohexyl) ethyl-trimethoxysilane (ECET) and (3-glycidyloxypropyl) methyldiethoxysilane (GLYMS) with the primary amine (3-aminopropyl) triethoxysilane (ATS) leads to solids that have been investigated by means of TG-DTA, FT-Raman and FT-IR spectroscopy. Solution 13C NMR and solid state FT-Raman spectra show that the oxirane ring of ECET is not involved in the epoxy-amine addition. The structure of the resulting materials consists of a siloxane network with pendant ...

Polymer, 2002

The epoxy monomer 3-glycidoxypropyltrimethoxysilane reacts, under non-hydrolytic conditions, with... more The epoxy monomer 3-glycidoxypropyltrimethoxysilane reacts, under non-hydrolytic conditions, with the primary amine (3aminopropyl)triethoxysilane in 2:1 (1), 5:1 (2) and 10:1 (3) molar ratios leading to epoxy-silica materials which were characterized by TGA, DSC, Raman, and NMR investigations. The epoxy ring opening and the hydrolysis reactions of the Si(OR) 3 groups were examined by means of 13 C NMR before gelation occurs. The identification of the different types of silicate substructures present in the solids 1, 2 and 3 was accomplished by 29 Si CP-MAS NMR spectroscopy which also provides a quantitative measure of the degree of condensation through the relative abundance of T 0 [RSi(OR) 3 ], T 1 [RSi(OR) 2 OSi], T 2 [RSi(OR)(OSi) 2 ] and T 3 [RSi(OSi) 3 ] silicon nuclei. The combined results of the Raman and 29 Si CP-MAS investigations clearly show that all the mixtures, especially the higher ratio ones, are characterized by a high degree of cross-linking; in addition, for 2 and 3, residual epoxy fragments are still present in the solid structure. The absence of residual enthalpy curing peaks in the calorimetric analysis indicates that the volatiles are simply released from all the samples. The thermogravimetric analysis shows that, among all the mixtures, 1 is featured by different structural properties which cause a higher degradation temperature and a longer decomposition time. To evaluate the effect of different experimental conditions on the properties of the final products, the reactions were also performed in the presence of small amounts of KOH and of a stoichiometric amount of water to effect hydrolysis of Si(OR) 3 groups.

Macromolecules, 1999

ABSTRACT The semidilute and concentrated solutions have been extensively investigated, but many q... more ABSTRACT The semidilute and concentrated solutions have been extensively investigated, but many questions are still unsolved. The present work, by means of photon correlation spectroscopy investigation on PMMA/acetone solutions, aims to add new information to the comprehension of the existence of a long time contribution in the autocorrelation functions in semidilute solutions together with the fast diffusive modes. On the basis of our results we follow the idea of the intervention of elastic and stress relaxation of the network constituted by the entangled polymer chains. Moreover, we think that the observation of the slow modes can be attributed not only to the existence of entanglements but also to the effect that the monomer structure produces on the entanglement phenomenon itself.

Le Journal de Physique IV, 2000

ABSTRACT The dynamic scattering function of dilute polymer solutions, in the temporal range 10(6)... more ABSTRACT The dynamic scattering function of dilute polymer solutions, in the temporal range 10(6) + 10(-2) s, is usually dominated by the relaxation of concentration fluctuations. The study of these modes allows to characterize the diffusive properties of the system. By increasing concentration up to the semidilute limit, the entanglement of the polymer chains leads to the appearance of new dynamical processes. We report results of a comparative study on Polyalkylmethacrylates (i.e. Poly(Methyl MethAcrylate (PMMA), Poly(Ethyl MethAcrylate) (PEMA) and Poly(Buthyl MethAcrylate) (PBMA)) in acetone solutions, in the semidilute regime. We will show that, besides a collective diffusive mode, a slow (similar to 10(-1) s) q-independent relaxation is present for PMMA and PEMA.

AIP Advances

Electrospray ionization (ESI) is a widely adopted soft ionization method for mass spectroscopy (M... more Electrospray ionization (ESI) is a widely adopted soft ionization method for mass spectroscopy (MS). In spite of the undeniable success of the technique, its mechanisms are difficult to be analytically modelled because the process is characterized by non-equilibrium conditions. The common belief is that the formation of gas-phase ions takes place at the apex of the Taylor cone via electrophoretic charging. The charge balance implies that a conversion of electrons to ions should occur at the metal-liquid interface of the injector needle. We have detected that the above description is based on unproved assumptions which are not consistent with the correct evaluation of the problem. The comparison between experiments performed under the usual geometry and observations obtained under symmetric field configurations suggests that the emitted droplets cannot be significantly charged or, at least, that any possible ionization mechanism is so poorly efficient to ensure that columbic forces c...

The Journal of …, 2007

The nature of the interactions between a representative room-temperature ionic liquid, namely 1-b... more The nature of the interactions between a representative room-temperature ionic liquid, namely 1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM][BF(4)]) and a common organic solvent, acetonitrile (CH(3)CN) has been investigated by means of Brillouin light scattering, over the whole concentration range and in the temperature range from -20 to 45 degrees C. Negative deviations from the ideal behavior of both molar volumes and adiabatic compressibility have been observed. This result has been interpreted within the framework of a well-established theoretical model, namely a nonadditive hard-sphere mixture. Despite that similar findings were rationalized in terms of enhanced interactions between molecules, a more detailed analysis of excess thermodynamic functions indicates that they are mainly due to excluded volume effects and that the differences in local intermolecular interactions act as higher order contributions: we have found that this can be a general feature of liquid mixtures. On this basis we present a reconsideration for excess thermodynamic data and for their role in providing direct information on intermolecular interactions.

Molecules

Surface Enhanced Raman Spectroscopy is commonly used as analytical improvement to conventional Ra... more Surface Enhanced Raman Spectroscopy is commonly used as analytical improvement to conventional Raman spectroscopy, able to respond to qualitative diagnostic enquiries, which involve low-concentrated molecular species in complex matrix. In this paper, we described fabrication, characterization and testing of a type of SERS-active substrates realized specifically to detect pigments in work of art. In particular, we detailed the SERS activity of nanostructured noble metal films deposited by pulsed laser ablation onto glass and polishing sheets substrates. The SERS response of the substrates was tested against the presence of some organic dyes in aqueous solutions. Measurements were performed at different pH values, in acidic or basic range, in order to investigate its role in the adsorption mechanism, thus fostering the SERS amplification. In addition, we checked the possible deterioration of the structural properties of the substrates that could occur in presence of alkaline or acidic...

Applied Sciences

The archaeometric study of the frescoes by the painter Saturnino Gatti (1463–1518) in the apse of... more The archaeometric study of the frescoes by the painter Saturnino Gatti (1463–1518) in the apse of the Church of San Panfilo in Villagrande di Tornimparte (L’Aquila) was the subject of the II National Research Project [...]

Applied Sciences

This paper reports the investigation of six microsamples collected from the vault of the San Panf... more This paper reports the investigation of six microsamples collected from the vault of the San Panfilo Church in Tornimparte (AQ). The aim was to detect the composition of the pigments and protective/varnishes, and to investigate the executive technique, the conservation state, and the evidence of the restoration works carried out in the past. Six microsamples were analyzed by optical microscopy, scanning electron microscopy coupled with energy-dispersive spectroscopy (EDS), X-ray fluorescence (XRF), and infrared and Raman spectroscopy. The investigations were carried out within the framework of the Tornimparte project “Archeometric investigation of the pictorial cycle of Saturnino Gatti in Tornimparte (AQ, Italy)” sponsored in 2021 by the Italian Association of Archeometry (AIAr).

Proceedings of the 2022 IMEKO TC4 International Conference on Metrology for Archaeology and Cultural Heritage

The Roman thermae in Reggio Calabria (Italy) provides many information regarding both engineering... more The Roman thermae in Reggio Calabria (Italy) provides many information regarding both engineering and technology for this type of buildings. A small treasure of three survived mural paintings encloses information about the artistic style and the ancient luxury of the baths. In order to get light on the executive technique and conservation state we performed the investigation of these paintings by following a non-invasive approach composed of multispectral imaging and spectroscopic analysis. By so doing, we determined the pigment palette and the distribution of some pigments allowing us to make some hypothesis about the executive technique and to provide a basis for a future virtual restoration of the paintings.

Materials Letters

The Neolithic painted pottery, spread all over southern Italy, is considered as an important chro... more The Neolithic painted pottery, spread all over southern Italy, is considered as an important chronological indicator for the development of VI-V millennium BC prehistoric settlements and cultural traditions. The goal of this work is to contribute to the study of this ceramic class through the chemical characterization of some samples coming from the Aeolian Islands. 16 different sherds have been selected and the pigments preserved in their decorations analyzed via non-invasive techniques: Fiber Optical Reflectance Spectroscopy (FORS), X-ray Fluorescence (XRF), Raman Spectroscopy and Infrared Spectroscopy (FT-IR). The different pigments, some of which no longer clearly visible to the naked eye (red ochre and raw umber) were identified, while the FT-IR data provided information about the pottery differentiation.

Virtual Archaeology Review

The new tools for 3D survey and modelling (as portable scanners and software packages), often in ... more The new tools for 3D survey and modelling (as portable scanners and software packages), often in combination with diagnostics, are nowadays able to provide indispensable elements for the study of archaeological artefacts; their applications to museum’s heritage can be also useful to integrate the traditional graphic documentation and contribute to enhancement and dissemination. This paper shows the benefit of using the aforementioned tools to study the peculiar clay mask No. 11114-E, discovered in 1973 in the Greek necropolis of Lipára, inside tomb No. 1558. The specimen, now exhibited in the Classical Section of the Aeolian Museum, is considered unique both in the Aeolian Islands and in the ancient Greek world, as it is the only one merging two half faces attributable to different characters. This feature, unknown at the time of discovery, has been highlighted in 2018, thanks to a restoration intervention by which a hard concretion layer covering a large portion of the mask surface...

Applied Sciences, 2022

Arsenic is a well-known contaminant present in different environmental compartments and in human ... more Arsenic is a well-known contaminant present in different environmental compartments and in human organs and tissues. Inorganic As(III) represents one of the most dangerous arsenic forms. Its toxicity is attributed to its great affinity with the thiol groups of proteins. Considering the simultaneous presence in all environmental compartments of other common functional groups, we here present a study aimed at evaluating their contribution to the As(III) complexation. As(III) interactions with four (from di- to hexa-) carboxylic acids, five (from mono- to penta-) amines, and four amino acids were evaluated via experimental methods and, in simplified systems, also by quantum-mechanical calculations. Data were analyzed also with respect to those previously reported for mixed thiol-carboxylic ligands to evaluate the contribution of each functional group (-SH, -COOH, and -NH2) toward the As(III) complexation. Formation constants of As(III) complex species were experimentally determined, an...

Remote Sensing, 2022

Cultural places represent the tangible part of the identity and historical heritage of a civiliza... more Cultural places represent the tangible part of the identity and historical heritage of a civilization as well as an extraordinary driving force for the economic development of a country. Within its huge asset, Italy counts a wide number of archaeological sites and monuments which, despite their cultural value, are totally cut off from the most important cultural routes. This paper aims to demonstrate how specific actions of digitization can contribute to valorize (restoring a cultural value) ‘marginal’ landmarks, promoting their knowledge and inclusion. The case study described is represented by the Church of “Santa Maria delle Palate”, located inside the well-known Archaeological Park of Halaesa Arconidea (Tusa, ME). The church, built in 1551 and subject to several renovations throughout the centuries, has been investigated as part of an interdisciplinary training and skill transfer project carried out by a CNR-IPCF research team. During the activities, the group of trainees approa...

Liquids, 2022

An experimental and computational study on the hydrolysis of Al3+ in aqueous solutions is here re... more An experimental and computational study on the hydrolysis of Al3+ in aqueous solutions is here reported. Speciation model and formation constants were determined by potentiometric titrations at T = 298.15 K, 0.1 ≤ I/mol L−1 ≤ 1 in aqueous NaCl, NaNO3, NaCl/NaNO3 solutions. The dependence of formation constants on ionic strength is reported in all the ionic media over the range of 0.1–1.0 mol L−1. Under the studied experimental conditions, the formation of Al3(OH)45+ and Al13(OH)327+ species is observed in all the investigated ionic media and ionic strengths. The formation constants of the species formed by Al3+ with Cl− were determined together with the dependence on the ionic strength. Moreover, with the aim of unveiling the molecular structure of the formed Al complexes, quantum-mechanical calculations and state-of-the-art ab initio molecular dynamics simulations under explicit solvation were executed. These computations show, for the first time, the highly cooperative role played...

Molecules, 2021

Spectral preprocessing data and chemometric tools are analytical methods widely applied in severa... more Spectral preprocessing data and chemometric tools are analytical methods widely applied in several scientific contexts i.e., in archaeometric applications. A systematic classification of natural powdered pigments of organic and inorganic nature through Principal Component Analysis with a multi-instruments spectroscopic study is presented here. The methodology allows the access to elementary and molecular unique benchmarks to guide and speed up the identification of an unknown pigment and its recipe. This study is conducted on a set of 48 powdered pigments and tested on a real-case sample from the wall painting in S. Maria Delle Palate di Tusa (Messina, Italy). Four spectroscopic techniques (X-ray Fluorescence, Raman, Attenuated Total Reflectance and Total Reflectance Infrared Spectroscopies) and six different spectrometers are tested to evaluate the impact of different setups. The novelty of the work is to use a systematic approach on this initial dataset using the entire spectrosco...

Many-body Approaches at Different Scales, 2018

In this note we revisit the Kovacs effect, concerning the way in which the volume of a glass-form... more In this note we revisit the Kovacs effect, concerning the way in which the volume of a glass-forming liquid, which has been driven out of equilibrium, changes with time while the system evolves towards a metastable state. The theoretical explanation of this phenomenon has attracted much interest even in recent years, because of its relation with some subtle aspects of the still elusive nature of the glass transition. In fact, even if there is a rather general consensus on the fact that what is experimentally observed on cooling is the dramatic effect produced by the dynamical arrest of slower degrees of freedom over the experimental time scale, it is not yet clear whether this phenomenology can be justified upon assuming the existence of an underlying (possibly, high order) phase transition at lower temperatures. liquids liquids!supercooled supercooled liquids Kovacs effect ortho-terphenyl

Journal of Analytical Atomic Spectrometry, 2017

This work presents the first neutron characterization of artefacts from the grave-goods of Kha an... more This work presents the first neutron characterization of artefacts from the grave-goods of Kha and Merit, a unique cultural treasure of mankind and preserved at the Museo Egizio in Turin.

AIP Conference Proceedings, 2000

This paper describes the importance of watermarks reproduction, in particular the advantages and ... more This paper describes the importance of watermarks reproduction, in particular the advantages and potentiality of beta-ray technique's application to this aim is emphasized. The method involved a radioactive carbon sheet which emits radiation that images a photographic film. After a conventional processing the film produces an exact copy of the watermark. Techniques which give similar results are also considered. .

Annali di chimica

This paper presents the results of a study that is part of a wider research program regarding the... more This paper presents the results of a study that is part of a wider research program regarding the knowledge of the initial living phases of Sicilian agricultural and pastoral societies. Three ceramic samples attributed to the medium initial Neolithic (NEO1 and NEO2) and to the first neolithic (NEO3), recovered in two different archaeological sites of the western Sicily, have been analysed. Chemical, mineralogical and spectroscopic data point out a similarity between NEO1 and NEO3 samples; compositional and morphological differences instead have been observed in the NEO2 sample. The firing temperatures of the samples have been estimated by Mössbauer spectroscopy; they are lower than 500 degrees C for the samples NEO1 and NEO3, and about 700 degrees C for NEO2.

Polymer, 2005

The reaction of the epoxy derivatives 2-(3, 4-epoxycyclohexyl) ethyl-trimethoxysilane (ECET) and ... more The reaction of the epoxy derivatives 2-(3, 4-epoxycyclohexyl) ethyl-trimethoxysilane (ECET) and (3-glycidyloxypropyl) methyldiethoxysilane (GLYMS) with the primary amine (3-aminopropyl) triethoxysilane (ATS) leads to solids that have been investigated by means of TG-DTA, FT-Raman and FT-IR spectroscopy. Solution 13C NMR and solid state FT-Raman spectra show that the oxirane ring of ECET is not involved in the epoxy-amine addition. The structure of the resulting materials consists of a siloxane network with pendant ...

Polymer, 2002

The epoxy monomer 3-glycidoxypropyltrimethoxysilane reacts, under non-hydrolytic conditions, with... more The epoxy monomer 3-glycidoxypropyltrimethoxysilane reacts, under non-hydrolytic conditions, with the primary amine (3aminopropyl)triethoxysilane in 2:1 (1), 5:1 (2) and 10:1 (3) molar ratios leading to epoxy-silica materials which were characterized by TGA, DSC, Raman, and NMR investigations. The epoxy ring opening and the hydrolysis reactions of the Si(OR) 3 groups were examined by means of 13 C NMR before gelation occurs. The identification of the different types of silicate substructures present in the solids 1, 2 and 3 was accomplished by 29 Si CP-MAS NMR spectroscopy which also provides a quantitative measure of the degree of condensation through the relative abundance of T 0 [RSi(OR) 3 ], T 1 [RSi(OR) 2 OSi], T 2 [RSi(OR)(OSi) 2 ] and T 3 [RSi(OSi) 3 ] silicon nuclei. The combined results of the Raman and 29 Si CP-MAS investigations clearly show that all the mixtures, especially the higher ratio ones, are characterized by a high degree of cross-linking; in addition, for 2 and 3, residual epoxy fragments are still present in the solid structure. The absence of residual enthalpy curing peaks in the calorimetric analysis indicates that the volatiles are simply released from all the samples. The thermogravimetric analysis shows that, among all the mixtures, 1 is featured by different structural properties which cause a higher degradation temperature and a longer decomposition time. To evaluate the effect of different experimental conditions on the properties of the final products, the reactions were also performed in the presence of small amounts of KOH and of a stoichiometric amount of water to effect hydrolysis of Si(OR) 3 groups.

Macromolecules, 1999

ABSTRACT The semidilute and concentrated solutions have been extensively investigated, but many q... more ABSTRACT The semidilute and concentrated solutions have been extensively investigated, but many questions are still unsolved. The present work, by means of photon correlation spectroscopy investigation on PMMA/acetone solutions, aims to add new information to the comprehension of the existence of a long time contribution in the autocorrelation functions in semidilute solutions together with the fast diffusive modes. On the basis of our results we follow the idea of the intervention of elastic and stress relaxation of the network constituted by the entangled polymer chains. Moreover, we think that the observation of the slow modes can be attributed not only to the existence of entanglements but also to the effect that the monomer structure produces on the entanglement phenomenon itself.

Le Journal de Physique IV, 2000

ABSTRACT The dynamic scattering function of dilute polymer solutions, in the temporal range 10(6)... more ABSTRACT The dynamic scattering function of dilute polymer solutions, in the temporal range 10(6) + 10(-2) s, is usually dominated by the relaxation of concentration fluctuations. The study of these modes allows to characterize the diffusive properties of the system. By increasing concentration up to the semidilute limit, the entanglement of the polymer chains leads to the appearance of new dynamical processes. We report results of a comparative study on Polyalkylmethacrylates (i.e. Poly(Methyl MethAcrylate (PMMA), Poly(Ethyl MethAcrylate) (PEMA) and Poly(Buthyl MethAcrylate) (PBMA)) in acetone solutions, in the semidilute regime. We will show that, besides a collective diffusive mode, a slow (similar to 10(-1) s) q-independent relaxation is present for PMMA and PEMA.

AIP Advances

Electrospray ionization (ESI) is a widely adopted soft ionization method for mass spectroscopy (M... more Electrospray ionization (ESI) is a widely adopted soft ionization method for mass spectroscopy (MS). In spite of the undeniable success of the technique, its mechanisms are difficult to be analytically modelled because the process is characterized by non-equilibrium conditions. The common belief is that the formation of gas-phase ions takes place at the apex of the Taylor cone via electrophoretic charging. The charge balance implies that a conversion of electrons to ions should occur at the metal-liquid interface of the injector needle. We have detected that the above description is based on unproved assumptions which are not consistent with the correct evaluation of the problem. The comparison between experiments performed under the usual geometry and observations obtained under symmetric field configurations suggests that the emitted droplets cannot be significantly charged or, at least, that any possible ionization mechanism is so poorly efficient to ensure that columbic forces c...

The Journal of …, 2007

The nature of the interactions between a representative room-temperature ionic liquid, namely 1-b... more The nature of the interactions between a representative room-temperature ionic liquid, namely 1-butyl-3-methyl imidazolium tetrafluoroborate ([BMIM][BF(4)]) and a common organic solvent, acetonitrile (CH(3)CN) has been investigated by means of Brillouin light scattering, over the whole concentration range and in the temperature range from -20 to 45 degrees C. Negative deviations from the ideal behavior of both molar volumes and adiabatic compressibility have been observed. This result has been interpreted within the framework of a well-established theoretical model, namely a nonadditive hard-sphere mixture. Despite that similar findings were rationalized in terms of enhanced interactions between molecules, a more detailed analysis of excess thermodynamic functions indicates that they are mainly due to excluded volume effects and that the differences in local intermolecular interactions act as higher order contributions: we have found that this can be a general feature of liquid mixtures. On this basis we present a reconsideration for excess thermodynamic data and for their role in providing direct information on intermolecular interactions.

Molecules

Surface Enhanced Raman Spectroscopy is commonly used as analytical improvement to conventional Ra... more Surface Enhanced Raman Spectroscopy is commonly used as analytical improvement to conventional Raman spectroscopy, able to respond to qualitative diagnostic enquiries, which involve low-concentrated molecular species in complex matrix. In this paper, we described fabrication, characterization and testing of a type of SERS-active substrates realized specifically to detect pigments in work of art. In particular, we detailed the SERS activity of nanostructured noble metal films deposited by pulsed laser ablation onto glass and polishing sheets substrates. The SERS response of the substrates was tested against the presence of some organic dyes in aqueous solutions. Measurements were performed at different pH values, in acidic or basic range, in order to investigate its role in the adsorption mechanism, thus fostering the SERS amplification. In addition, we checked the possible deterioration of the structural properties of the substrates that could occur in presence of alkaline or acidic...