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In this work, we have studied the pH-dependence of the formation of DQCB[8] complexes by surface-enhanced Raman scattering (SERS) spectroscopy. The SERS spectra suggest that at acidic pH CB[8] can form a binary complex with the dication DQ+2 while at higher pH ternary complexes with the radical cation dimer (DQ+ )2 and the radical cation–dication dimer(DQ+ DQ+2) are formed. The pH-enhanced diquat (DQ) dimerization inside the cucurbit[8]uril cavity has not been reported until now. In addition, this study provides very valuable information regarding the use of CB[8] functionalized silver nanoparticles as SERS substrate for sensing applications.© Royal Society of Chemistry 2012

In this work, surface-enhanced Raman scattering (SERS) and surface-enhanced fluorescence (SEF) were employed in the study of the adsorption and detection of the pigments quinacridone (QA) and 2,9-dimethylquinacridone (2,9-DMQA). These pigments are of great relevance in artwork and textile, plastic, and photochemical industries due to their condition as high performance pigments since they possess a high tinting strength. Due to this fact, they have been employed at relatively low concentrations. Therefore, the analysis and detection of these pigments requires the application of a highly sensitivity technique, such as SERS and SEF. The adsorption of QA and 2,9-DMQA on silver nanoparticles was extensively studied by means of SERS at different surface coverages. This study was completed by carrying out an in depth vibrational (Raman and IR) analysis of these pigments in solid state by ab initio density functional theory (DFT) calculations. In addition, UV-vis spectroscopy was employed to investigate the aggregation undergone by both pigments in solid state and in solution. 2,9-DMQA was demonstrated to have a lower tendency toward aggregation due to the presence of methyl groups. Even so, this molecule follows a BET adsorption mechanism on the metal nanoparticles due to its high tendency toward intermolecular interaction. From the analysis of the adsorption mechanism of this molecule, the limit of detection was deduced to be ca. 55 ppb. © 2013 American Chemical Society.

The development of effective array biosensors relies heavily on careful control of the density of surface-immobilized ligands on the transducing platform. In this paper we describe the synthesis of new dextran-lipase conjugates for use in immobilizing low molecular weight haptens onto glass planar waveguides for immunosensor development. The conjugates were synthesized by immobilizing bacterial thermoalkalophilic lipases (Geobacillus thermocatenulatus lipase 2, BTL2) on agarose macroporous beads, followed by covalent coupling to dextran networks of variable molecular weight (1500-40000). The chimeras were immobilized via nonspecific hydrophobic interactions onto glass planar waveguides modified with 1,1,1,3,3,3-hexamethyldisilazane to obtain highly ordered and homogeneous molecular architectures as confirmed by atomic force microscopy. Microcystin LR (MCLR) was covalently bound to the dextran-BTL2 conjugates. The usefulness of this approach in immunosensor development was demonstrated by determining amounts of MCLR down to a few picograms per liter with an automated array biosensor and evanescent wave excitation for fluorescence measurements of attached DyLight649-labeled secondary antibody. Modifying BTL2 with dextrans of an increased molecular weight (>6000) provided surfaces with an increased loading capacity that was ascribed to the production of three-dimensional surfaces by the effect of analyte binding deep in the volume, leading to expanded dynamic ranges (0.09-136.56 ng L -1), lower limits of detection (0.007 ± 0.001 ng L -1), and lower IC50 values (4.4 ± 0.7 ng L -1). These results confirm the effectiveness of our approach for the development of high-performance biosensing platforms. © 2013 American Chemical Society.

Synthesis of asymmetric nanoparticles, such as gold nanorods, with tunable optical properties providing metal structures with improved SERS performance is playing a critical role in expanding the use of SERS to imaging and sensing applications. However, the synthetic methods usually require surfactants or polymers as shape-directing agents. These chemicals normally remain firmly bound to the metal after the synthesis, preventing the direct adsorption of a large number of potential analytes and often hampering the chemical functionalization of the surface unless extended, and critical for the nanoparticle stability, postremoval steps were performed. For this reason, it is of great importance for the full exploitation of these nanostructures to gain a deeper insight into the dependence of the analyte-metal interaction to the metal-liquid interface composition. In this article, we investigated in detail the role played by each component of the gold nanorod (GNR) interface in the adsorption of indocyanine green (ICG) as a probe molecule. Citrate-reduced gold nanospheres were used as a model substrate since the negative citrate anions adsorbed onto the metal surface can be easily displaced by those chemicals usually involved in the GNR synthesis, allowing the GNR-like interface composition to be progressively rebuilt and modified at will on the citrate-capped nanoparticles. The obtained results provide a meticulous description of the role played by each individual component of the metal-liquid interface on the ICG interaction with the metal, illustrating how apparently minor experimental changes can dramatically modify the affinity and optical properties of the ICG probe adsorbed onto the nanoparticle. © 2013 American Chemical Society.

SERS detection of quinacridone quinone (QAQ), an insoluble synthetic organic pigment relevant to modern artworks, is reported here. The use of ionic liquids (BMIMCl and TBAN) as dispersing agents has allowed us to carry out electrochemical SERS experiments of QAQ in aqueous solution using a Cu electrode. No SERS spectra were obtained either from the ionic liquids (ILs) or from QAQ when silver/gold colloids were employed. The spectra of the Cu electrode in 0.1 M KCl aqueous solutions containing either BMIMCl or TBAN indicate that the corresponding cations approach the metal surface through formation of an ion pair with specifically adsorbed Cl¿, but the corresponding cyclic voltammograms only show reduction and oxidation of the Cu surface. In the case of QAQ dispersed in BMIMCl and TBAN, two different SERS spectra due to QAQ species are observed between ¿0.4 and ¿1.0 V. One of the spectra agrees with the SERS of QAQ previously reported by us, using calixarenes as dispersing agents and silver colloids as SERS substrates. The other spectrum reveals a reallocation of the charge of the QAQ molecule, concomitant with a change in its relative orientation to the Cu surface. The SERS detection of QAQ is free from interferences of bands corresponding to the ILs.

In this Letter, we report on the successful fabrication of low loss, high refractive index contrast waveguides via ion migration upon femtosecond laser writing in phosphate glass. Waveguides were produced in two different phosphate glass compositions with high and low La2O3 content. In the La-rich glass, a large refractive index increase in the guiding region was observed due to the incoming migration of La accompanied by the out-diffusion of K. The much smaller refractive index change in the La-less glass is caused by rearrangements of the glass structure. These results confirm the feasibility of adapting the glass composition for enabling the laser writing of high refractive index contrast structures via spatially selective modification of the glass composition. © 2013 Optical Society of America.

In this study, the reaction of widely used artist's pigments in raw form to pulsed laser radiation of different wavelengths and pulse duration was investigated. Vermilion, lead chromate and malachite (in the form of pellets) were irradiated using laser pulses of 500 fs at 248 nm, and pulses of 150 ps and 15 ns at 1064 and 213 nm. Optical microscopy, colorimetry, spectrofluorimetry, micro-Raman spectroscopy and X-ray photoelectron spectroscopy were employed to characterize the physicochemical changes induced to the pigments. Change of crystalline phase was identified for vermilion while reduction processes take place for lead chromate and malachite. It was found that these effects were minimized by application of ultraviolet ultrashort pulses (of femtosecond and picosecond duration) as compared with changes occurring by pulsed infrared irradiation (of both picosecond and nanosecond duration). The results presented are discussed in relation to previous research on painted mock-ups in order to elucidate the role and significance of the binding media in the laser induced discoloration of painted surfaces and thus to propose optimum laser cleaning practices. © 2012 Elsevier B.V. All rights reserved.

In this work the changes in the infrared absorption of N2O observed in a hollow cathode discharge modulated by a 45 Hz square wave are studied by time-resolved infrared absorption spectroscopy, with a Fourier transform infrared (FTIR) spectrometer working in the step-scan mode. These variations are attributed to alternative population and depopulation of the ground state of N2O; on the other hand, no changes are observed in the total concentration of N2O and the major products of the discharge. The experimental results are explained by means of a simple kinetic model: vibrational excitation processes are assumed to be the main cause of the observed effects, but an inhomogeneous distribution of the stable species and the incorporation of diffusion terms between the plasma volume and the rest of the discharge cell are shown to be crucial in order to justify the quick and sharp variations in the N2O ground-state population seen along the path of the IR beam. The influence of these effects has been verified also by mass spectrometric measurements of the temporal behavior of the concentration of the major products N2O, N2 and O2 at one end of the discharge cell and at different frequencies.© 2000 American Chemical Society

In this work, a single-step synthesis route to prepare lauryl gallate capped TiO 2 nanoparticles has been established. Powder X-Ray diffraction analysis shows anatase as the predominant inorganic phase. UV-vis and FT-IR spectroscopy characterization denotes that lauryl gallate molecules are covalently linked to the particulate titania core through the enediolate group. The as prepared powder is easily dispersable in common organic solvents, such as tetrahydrofurane, methylethylketone and n-butanol, showing good stability under ambient atmosphere. This solution processable precursor facilitates thin film deposition on glass substrates. The capping gallate derivative also facilitates preparing translucent TiO 2-polystyrene composites. © 2012 Elsevier B.V.

We report on the fabrication of gold coated nanostructured polymer thin films and on their characterization as substrates for surface enhanced Raman spectroscopy (SERS). Laser induced periodic surface structures (LIPSS) were obtained on thin polymer films of poly(trimethylene terephthalate) (PTT) upon laser irradiation with the fourth harmonic of a Nd:YAG laser (266 nm, pulse duration 6 ns) resulting in a period close to the incident wavelength. The nanostructured polymer substrates were coated with a nanoparticle assembled gold layer by pulsed laser deposition using the fifth harmonic of a Nd:YAG laser (213 nm, pulse duration 15 ns). Different deposition times resulted in thicknesses from a few nanometres up to several tens of nanometres. Analysis by atomic force microscopy and grazing incident small angle X-ray scattering showed that gold coating preserved the LIPSS relief. The capabilities of the produced nanostructures as substrates for SERS have been investigated using benzenethiol as a test molecule. The SERS signal is substantially larger than that observed for a gold-coated flat substrate. Advantages of this new type of SERS substrates are discussed.

Raman and surface-enhanced Raman scattering spectroscopy were used to follow the chemical modification of quercetin (QUC) on silver nanoparticles. Different metallic systems were fabricated to check the influence of the interface, in terms of electric charge or total available surface, on the catalytic change undergone by QUC. The effect of QUC surface coverage was crucial to reveal information about the different orientation and the interaction mechanism with the metal at different concentrations of this flavonoid. Surface-enhanced Raman scattering spectra of good quality of QUC were observed at concentrations down to 10-8 M. Chemical modifications in the presence of nanostructure metal surfaces include oxidation followed by a subsequent polymerization via a condensation of rings whereas different chemical species have been recognized under different experimental conditions. The assignment of the new species formed on the metal surface was conducted. Copyright © 2012 John Wiley & Sons, Ltd.

Las nanoestructuras metálicas presentan propiedades ópticas singulares debido a los plasmones superficiales localizados (Localized Surface Plasmons) que soportan. La excitación resonante de los mismos produce enormes intensificaciones del campo electromagnético local en las proximidades de las nanoestructuras metálicas, efecto que puede aprovecharse para aumentar la sensibilidad de las técnicas de espectroscopía vibracional (dispersión Raman y absorción infrarroja) que son idóneas para llevar a cabo la caracterización requerida en un sensor molecular. Cuando las moléculas a detectar no presentan afinidad por los sustratos metálicos, se hace necesario funcionalizarlos adecuadamente para conseguir que esas moléculas se aproximen lo suficiente a las nanoestructuras metálicas como para que se beneficien de los enormes campos electromagnéticos locales y, por lo tanto, puedan ser detectadas mediante las técnicas de espectroscopía vibracional intensificadas SERS (Surface-enhanced Raman Scattering)y/o SEIRA (Surface-enhanced Infrared Absorption). Se presentan ejemplos de detección con esta técnicas de cantidades traza de moléculas de interés biológico y/ o medioambiental, utilizando sustratos metálicos nanoestructurados preparados por diferentes métodos.

A possibility of getting SERS spectra of insoluble aromatic compounds in colloidal silver solutions is described. The method tested for the organic pigment quinacridone quinone consists of dispersing it in calix[n]arenes. The potentials of such cavitands, both as dispersing and as silver functionalization agents, is reported as a function of the substitution in their lower rim and their cavity size.

Surface-enhanced Raman spectroscopy (SERS) was used as a powerful surface analyzing tool to investigate the core–shell structural evolution of Au@Pt nanoparticles, revealing the templating role of the underlying Au atoms on the nanoscale Pt-phase structure in the sub-monolayer range.

In this work micro-Raman scattering experiments have been performed in LiNbO3:Tm3+ samples with waveguides fabricated by Zn 2+ indiffusion. The results shown that Zn2+ ions enter the lattice in Li+ sites, but also in interstitial positions. This produces a compaction of the lattice close to the surface of the sample, generating the waveguide. It is shown that this region is surrounded by a different area in which the lattice is relaxed to recover the characteristic lattice parameters of LiNbO3:Tm3+. © 2010 Optical Society of America.

Arrays of vertically aligned single-walled carbon nanotube bundles, SWCNTs, have been synthesized by simple alcohol catalytic chemical vapor deposition process, carried out at 800 °C. The formed SWCNTs are organized in small groups perpendicularly aligned and attached to the substrate. These small bundles show a constant diameter of ca. 30nm and are formed by the adhesion of no more than twenty individual SWCNTs perfectly aligned along their length. Copyright © 2010 Francisco Mrquez et al.

The application of laser cleaning methodologies to light-sensitive substrates such as those encountered in artistic paintings is an extremely delicate issue. The cleaning of paintings and polychromes is an irreversibly invasive intervention; therefore, prior to the implementation of laser cleaning methodologies, a thorough characterization of the interaction between laser pulses and painting components is required. In this work, the modifications induced by irradiation with pulses of 150 picoseconds (at 1064 and 213 nm) and 15 nanoseconds (at 213 nm) on unvarnished aged model egg-yolk-based paints were examined following a spectroanalytical approach. Laser-induced chemical changes on samples of unpigmented and widely used artist's pigment temperas were investigated by spectrofluorimetry and Fourier transform Raman spectroscopy, while color changes were quantified by colorimetry. Noticeable modifications of the Raman and fluorescence bands attributed to pigments are absent except for vermillion, for which the pigment bands tend to disappear upon irradiation at 1064 nm. Interestingly, no discoloration was observed on most of the pigments upon irradiation at 213 nm (150 ps), including the light-sensitive vermillion, while no indications of carbonization or charring of the paint layers, which could give rise to amorphous carbon bands, were obtained at any of the irradiation conditions explored. Comparison of the results using the two different pulse durations and wavelengths illustrates the participation of mechanisms of diverse origin according to the chemical composition of the pigment and highlights the importance of the optimization of the laser parameters, specifically fluence, pulse duration, and wavelength, in conservation treatments of paintings. © 2010 Society for Applied Spectroscopy.

Femtosecond lasers have been used for laser induced forward transfer (LIFT) of TiO2, a wide-band semiconductor with many industrial and research applications. TiO2 polycrystalline thin films on quartz (obtained by pulsed laser deposition) were used as donors and both quartz and fluorine-doped tin dioxide coated glass substrates as acceptors. LIFT was performed at the laser wavelengths of 248 and 800 nm with pulses of 450 and 300 fs respectively. The transferred material was characterized by energy-dispersive X-ray spectroscopy, X-ray diffraction and micro-Raman spectroscopy to determine the composition and crystalline quality, and by scanning electron microscopy and atomic force microscopy to assess the surface morphology. The relation between these properties and the laser transfer conditions, including wavelength, pulse energy and acceptor substrate, are presented. © 2010 Elsevier B.V.

Surface-enhanced Raman scattering (SERS) is an extremely powerful tool for the analysis of the composition of bimetallic nanoparticle (BNP) surfaces because of the different adsorption schemes adopted by several molecules on different metals, such as Au and Ag. The preparation of BNPs normally implies a change in the plasmonic properties of the core metal. However, for technological applications it could be interesting to synthesize core–shell structures preserving these original plasmonic properties. In this work, we present a facile method for coating colloidal gold nanoparticles (NPs) in solution with a very thin shell of silver. The resulting bimetallic Au@Ag system maintains the optical properties of gold but shows the chemical surface affinity of silver. The effectiveness of the coating method, as well as the progressive silver enrichment of the outermost part of the Au NPs, has been monitored through the SERS spectra of several species (chloride, luteolin, thiophenol and lucigenin), which show different behaviors on gold and silver surfaces. A growth mechanism of the Ag shell is proposed on the basis of the spectroscopic and microscopic data consisting in the formation and deposit of Ag clusters on the Au NP surface.

Metal nanostructures are known to amplify the spontaneous emission of fluorescent molecules by resonant coupling to external electromagnetic fields. We have used spectroscopy to characterize the structural properties of emodin molecules, a natural anthraquinone dye, and bovine serum albumin, the most abundant protein in plasma, in the presence of silver nanoparticles. Aggregation of emodin at pH=10 and pH=6 gives rise to SERS and MEF effects in silver colloid. We have obtained MEF spectra at acidic pH=2.9 using two different silver nanostructures. We have also studied the change in the secondary structure of bovine serum albumin adsorbed on metal nanoparticles surface. Circular dichroism, fluorescence emission and fluorescence lifetime measurements indicate an increase in the alfa-helical content of the protein and a change in the environment of the tryptophan residues that bury in the interior of the biomolecule. This variation on the secondary structure could have further influence in the binding of the drug to form transport and regulatory complexes.

Supercritical carbonation of Portland cement binders was studied to analyse the influence of the type of cement on carbonation at high CO2 pressures (CO2 at 20 MPa and 318 K) and to improve the understanding of the effects on the microstructure and physicochemical properties of binders. The results were compared with those obtained in a natural exposure. Microstructural properties of supercritically and atmospherically carbonated Portland cement binders were examined using the complementary analytical techniques of FTIR, TG-DTA, and BSEM-EDX. Supercritically carbonated binders showed a microstructure based on a more polymerized and lower Ca form of CSH gel, formed by decalcification of high-Ca form of CSH gel. Results suggested that during the treatment at artificially intensified conditions, the crystallized calcium carbonate came mainly from the carbonation of the CSH gel, and at atmospheric conditions, from the carbonation of the portlandite phase.

This study aims to analyze the effects of supercritical carbon dioxide (SCCO2) on the carbonation of Portland cement pastes, with and without mineral addition. The process is based on the advantages of the low viscosity and surface tension of SCCO2 that allow the complete wetting of complex substrates with intricate geometries, including internal surfaces of agglomerates such of these found in cement pastes. The supercritical treatment alters the bulk chemical and structural properties of cement pastes by accelerating natural carbonation reactions, while at the same time it reduces both free and bound water. The observed overall effects of supercritical carbonation on Portland cement pastes were the neutralization of pore water alkalinity, the formation of calcium carbonate and the reduction in the Ca/Si ratio of the calcium silicate hydrate (CSH) gel. Moreover, the massive precipitation of calcium carbonate inside microcracks after supercritical treatment caused the refinement of the microstructure, thus, reducing water permeability to a large extent. Supercritical carbonation method can be completed in few hours, rendering it technically interesting. This work also contributes to the idea of increasing the durability of concrete by means of a preventive hydrophobic supercritical treatment against water ingress. A generic SCCO2 method for concrete silanization is proposed here.

Luteolin and apigenin flavonoid have been detected in silk and wool fibres dyed with weld (Reseda luteola L.) through surface-enhanced Raman scattering (SERS) measurements carried out on the fibre. For such purpose, Ag nanoparticles were produced and immobilised in situ via the laser photoreduction of a silver nitrate water solution in contact with the fibre. Control SERS spectra of pure luteolin and apigenin, as well as of mixtures of them, on analogous Ag nanoparticles were also obtained. In this work flavonoids with a similar molecular structure were identified on dyed fibres for the first time without previously hydrolysing the mordant-dye complex.

Tellurite (TeO2–TiO2–Nb2O5) thin film glasses have been produced by pulsed laser deposition. The dispersion of the real and imaginary parts of the linear refractive index has been measured in the range from 300 to 1700 nm. Films present high refractive index (n=2.01) and reduced absorption (k<10−4) at =1500 nm. The nonlinear third order optical susceptibility (|(3)|) has been determined at four different wavelengths (600, 800, 1200, and 1500 nm). The out-of-resonance |(3)| values (~10−12 esu) are found to be ten times higher than those of the bulk glass and 102 times higher than that of silica. Compositional and structural analysis reveals an increase of both the Ti atomic content and the fraction of nonbridging oxygen bonds in the deposited films. Both factors lead to a higher hyperpolarizability of the film constituents that is proposed to be responsible for the high |(3)| value of the films.

Mesoporous silica, prepared in basic conditions, has been loaded (20% weight) with 12-molybdophosphoric (PMo) or 12-tungstophosphoric (PW) acid and calcined at different temperatures ranging between 250 and 550°C. The samples have been characterised by N2 adsorption–desorption at −196°C, transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), UV–visible diffuse reflectance, Raman spectroscopy and temperature programmed reduction (TPR). The acidity and catalytic activity have been, respectively, examined by monitoring the adsorption of pyridine and 2-butanol by FT-IR spectroscopy. The results indicate that PW and PMo acids are highly dispersed on mesoporous silica MCM-41 spherical nanoparticles. While PMo retains its Keggin structure up to 550°C, PW decomposes at this temperature into crystalline WO3 and phosphorous oxides. In both cases, the morphology, hexagonal symmetry and long-range order observed for the support are preserved with calcination up to 450°C. The Brönsted-type acid sites found in all samples, whose surface concentration decreases as the calcination temperature increases, are responsible for the selective formation of cis-butene detected upon adsorption of 2-butanol. The sample containing PW calcined at 450°C also shows selectivity to methyl ethyl ketone.

In this work, femtosecond (fs) laser irradiation of ancient parchment is evaluated as a novel cleaning technique that, in comparison with nanosecond (ns) irradiation, could considerably reduce the thermal and chemical damage to the substrate. To investigate the interaction of ultrashort laser pulses with parchment, two historical specimens were exposed to Ti:Sapphire laser using the fundamental and second harmonic emission (795 and 398 nm, 120 fs pulses). The ablation threshold fluences were determined resulting in values of 1.1 and 0.15 J/cm2 at 795 and 398 nm respectively. A study of the effects of the fs laser–parchment interaction as a function of fluence and wavelength was carried out and the results were compared with those obtained for Nd:YAG laser irradiation (532 and 355 nm, pulse duration 6 ns). FT-Raman spectra show the disappearance of the amorphous carbon bands upon fs treatment, indicative of the removal of the carbonaceous contamination of the parchment. At the same time the parchment structural bands remain unaffected. Spectrofluorimetric measurements reveal an enhancement of photodegradation products in the substrate. Results are discussed in terms of the comparison between expected mechanisms operating in the fs and ns irradiation regimes.

The application of viologen dications in the creation of highly sensitive and selective hot spots between silver nanoparticles is reported in the present work. A method to follow the existence of such hot spots in macroscopic samples is proposed based on the plasmon absorption of these nanoparticles in suspension. The method was applied in the case of detection of the polycyclic aromatic hydrocarbon pyrene, confirming the great ability of viologens, in the increasing of the sensitivity and selectivity of the SERS technique, as both hot spot inducers and host molecules.

The objective of this ongoing work is to improve the physical properties of Portland cement pastes and Portland-composite cement pastes containing silica fume and/or fly ash through an accelerated carbonation process based on the use of SCCO2. Cement carbonation allows the preparation of cementitious composites reinforced with low-cost alkali-intolerant products and the use of these materials in solidification/stabilization of hazardous waste. In the supercritical treatment, results suggested that the carbonation rate of the portlandite phase slowed down after the first reaction stage and was overtaken by the reaction rate of the CSH and ettringite phases. Samples carbonated under the supercritical conditions developed a higher volume of gel pores than those obtained by natural carbonation. The microstructural analysis was completed by analyzing the water permeability of a cement paste/sand composite (mortar) after supercritical carbonation. Obtained values showed that supercritical carbonation reduced water permeability significantly

Pulsed laser deposition (PLD) has been used to obtain thin films of poly(methyl methacrylate) and polystyrene doped with fluorescent probes, amino aromatic compounds S5 and S6, that could be used to sense the presence of contaminating environmental agents. These dopants both in solution and inserted in polymeric films are sensitive to changes in pH, viscosity and polarity, increasing their fluorescence emission and/or modifying the position of their emission band. Films deposits on quartz substrates, obtained by irradiating targets with a Ti:Sapphire laser (800 nm, 120 fs pulse) were analyzed by optical and Environmental Scanning Electron Microscopy, Fluorescence Microscopy, Laser-Induced Fluorescence, Micro Raman Spectroscopy and Flow Injection Analysis-Mass Spectrometry. The transfer of the polymer and the probe to the substrate is observed to be strongly dependent on the optical absorption coefficient of the polymeric component of the target at the irradiation wavelength. © 2007 IOP Publishing Ltd.

This work presents the results of laboratory tests aiming at the characterization of painting materials by LIB and FT-Raman spectroscopies and at identification of the best laser cleaning conditions of polychromes of Spanish Heritage: polychromes on gypsum mortar of the Church-Fortress of Santa Tecla of Cervera de la Cañada, Zaragoza, fifteenth century, and appliqué relief brocades on wooden sculptures of the Chapel of San Miguel, Cathedral of Jaca, Huesca, sixteenth century.

The interaction between adsorbates of different nature and plasmonic nanoparticles is reviewed here on the basis of the work done in our laboratory in the past few years. The paper is structured for analyzing the interaction of adsorbates with metal nanoparticles as function of the interacting atom (O, N, or S) and the adsorbate conforma- tion. In the study of the adsorption of molecular species on metals, it is necessary to take into account that different interaction mechanisms are possible, leading to the exis- tence of different molecular forms (isomers or conformers). These forms can be evidenced by changing the excitation wavelength, due to a resonant selection of these wave- lengths. Charge-transfer complexes and electrostatic inter- actions are the usual driving forces involved in the interaction of adsorbates on metal surfaces when these metallic systems are used in wet conditions. The under- standing of the metal–adsorbate interaction is crucial in the surface functionalization of metal surfaces, which has a growing importance in the development of sensing systems

We report the effect of a combination of shear and elongational flow fields on the structure of nanoadditive and matrix for an injection moulded SWCNT-polymer nanocomposite. Single-wall carbon nanotubes (SWCNTs) intensify the flow field effects produced during injection moulding of a PBT/SWCNT nanocomposite, templating the morphology of crystallization and providing the generation of hybrid shish-kebab superstructures. By combining X-ray diffraction and Raman Spectroscopy techniques, both working on a microfocus fashion, it has been shown that the shear flow tends to self-assemble the nanotubes into a rectangular lattice, different from that hexagonal of native SWCNT, the maximum concentration of ordered aggregates being 1 mm to the wall edge of the injection moulded bar. © 2006 Elsevier Ltd. All rights reserved.