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Terpenoids play a major role in agriculture, given their fungicidal and herbicidal actions, as well as their favorable toxicological, ecotoxicological, and environmental profiles. Despite all these advantages, terpenoids are reported to be unstable in direct sunlight and atmospheric conditions, so both commercial suppliers and scientific literature foresee their protection by encapsulation. The so‐called microcapsules (μCaps) are therefore of high relevance as drug‐delivery vectors, but very few techniques focus on their surface as well as on their morphological characterization. Indeed, these aspects are of great importance, given that their surface chemistry governs both their colloidal stability and mechanism of action. Common analysis techniques, such as chromatographic and mass‐spectrometric ones, are destructive, require sample preparation, and do not result in the complete morphological characterization of the microcapsules. Micro‐Raman spectroscopy, in conjunction with the surface‐enhanced Raman spectroscopy (SERS) effect, offers a valuable alternative method of investigation capable of achieving a complete and non‐destructive morphological characterization of the terpenoid‐encapsulating systems, the dimensions of which fall within the micrometric range. In addition, the SERS effect can be exploited by fabricating the microcapsules with gold nanostars (AuNSs) modified with chitosan and a SERS reporter (Nile Blue A). Thanks to the high contrast provided by the SERS signals of this tag, it was possible to localize and confirm the chitosan in the morphology of the microcapsules. The results of this study shed new light on the possibility of analyzing terpenoid‐encapsulating microcapsules and possibly other kinds of encapsulates brought by using Raman spectroscopy and by exploiting the SERS effect. [ABSTRACT FROM AUTHOR]

In this article, the depositions and functional characterizations of Ta-N and Ta-Al-N coatings for protection purposes, grown by reactive high-power impulse magnetron sputtering onto silicon substrates, are described. Nitride films were grown while changing the substrate polarization voltage (i.e., the applied bias voltage) during the process. Moreover, the effects of adding Al to form a ternary system and the resulting variation of the coatings' mechanical and tribological properties have been widely investigated by nanoindentation, scratch, and wear tests. Micro-Raman characterization has been applied to the wear tracks to explore the comprehensive tribo-environment and wear mechanism. Interestingly, Ta-Al-N films, despite significantly improved mechanical properties, show a premature failure with respect to Ta-N coatings. The wear mechanisms of Ta-N and Ta-Al-N systems were revealed to be very different. Indeed, Ta-Al-N films suffer higher oxidation phenomena during wear, with the formation of an oxidized surface tribofilm and a reduced wear resistance, while Ta-N coatings undergo plastic deformation at the wear surface, with a slightly adhesive effect. [ABSTRACT FROM AUTHOR]

Gold nanoparticles are synthesized by laser ablation of a gold plate in toluene, which do not show their characteristic surface plasmon absorption (SPA) and are found to be included in graphitic matrix. The recovery of the nanoparticle SPA is possible by oxidizing the carbon matrix thereby obtaining some control on the activity of this absorption.

Measurement of the properties of magnetic nanoparticles is mandatory for their application and usually this is accomplished using magnetometers, like SQUIDs or VSMs. However, these techniques require amounts of materials that are not always available and do not allow exploration of new syntheses with low production. The tiny quantity of nanoparticles obtained by laser ablation of strontium ferrite necessitated the characterization of their magnetic properties using an alternative technique, optically detected magnetophoresis, which exploits the motion of nanoparticles in a fluid under a magnetic field gradient. Time dependent optical extinction of a colloidal solution of magnetic nanoparticles can be used for recording the collective motion of the nanoparticles in a fluid. The optical extinction of nanoparticles, with absorption and scattering contributions, depends on the particle material and on their morphologies. We report a new implementation of a magnetophoretic model with the extinction properties of nanoparticles calculated using the Boundary Element Method. The model is applied to estimate the magnetic properties of a challenging sample of mixed ferrite nanoparticles. The results show that, especially for polydisperse samples, the explicit consideration of the size dependent extinction properties of the nanoparticles is needed to characterize magnetic nanoparticles by optically detected magnetophoresis. The motion of magnetic nanoparticles in a fluid, exploited in many applications, is provided with an appropriate description using the present approach. [ABSTRACT FROM AUTHOR]

Surface enhanced Raman spectroscopy (SERS) is a highly sensitive technique for the non- or minimally invasive identification of molecules at very low concentrations. In this work, SERS is exploited using naked laser-ablated gold nanoparticles (AuNPs) for the detection of dyes on artificially aged paper inked with a ballpoint pen. Although several studies on inks with SERS are present in the literature, most of them report on the investigations on freshly prepared products, and less information is present on the detection of aged dyes and inks using SERS. Ballpoint inks are commonly used in daily activities, but have also been employed by several contemporary artists. These inks are very sensitive to light, and they discolor rapidly, making their detection demanding. In the present work, the SERS spectra of a ballpoint pen ink on two types of paper were analyzed after light-induced ageing, and the importance of the dye–AuNP interaction is discussed. The results show that the interpretation of the SERS spectra of the aged samples, such as those of interest in the Cultural Heritage field, is a tricky and delicate operation and that the diffusion of the dyes to the hot spot regions of the plasmonic nanoparticles plays a pivotal role in the detection of degraded ink components. Therefore, appropriate evaluation of the factors affecting the molecule–plasmonic nanoparticle interactions and of the history of the artwork to be analyzed is fundamental to avoiding the misinterpretation of the spectra and, consequently, of the original composition of the analyzed artwork. [ABSTRACT FROM AUTHOR]

In the field of nanomaterials, multifunctional nanosystems play a prominent role in many applications as new magnetically recoverable catalysts, information processing, fuel cells, efficient bio/nanosensors, and nanomedicine. Aiming at the obtainment of new nanomaterials for biotechnological applications such as biosensors or theragnostic systems, we present a multifunctional system able to merge different properties in only one nanotool. The system is prepared by loading the pores of mesoporous zirconia nanoparticles with CoFe2O4, by a wet impregnation method, further modifying the surface of the material with bis-(phosphonic acid) to load gold nanoparticles, produced by laser ablation. The obtained nanocomposite functionalized with a SERS probe represents a specific example of a magnetoplasmonic nanosystem. The results show the efficacy of the strategy of exploiting mesoporous zirconia nanoparticles for obtaining magnetoplasmonic nanotools. [ABSTRACT FROM AUTHOR]

A study was conducted to explore the photophysical properties of tetrakis-2,3-[5,6-di-(2-pyridyl)pyrazino]porphyrazinato-palladium(II), [[Py.sub.8]TPyzPzPd], its pentanuclear derivative [[(Pd[Cl.sub.2]).sub.4][Py.sub.8]TPyzPzPd], and the octacation [[[(2-Mepy).sub.8]TPyzPzPd].sup.8+].

The photophysical properties of four axially substituted indium phthalocyanines are examined and their optical limiting properties with nanosecond light pulses are evaluated. All complexes have behaved as reverse saturable absorbers due to a triplet-triplet excited-state transition.

A series of five hemiporphyrazines (Hps) with different coordinating central atoms and a acyclic derivative 1,3-bis-(6'-amino-4'-butoxy-2'-pyridylimino)-1,3-dihydroisoindoline are prepared and their multiphoton absorption properties are examined at the second harmonic frequency of the Nd:YAG laser in the nanosecond time regime. The large nonlinear absorption of Hps combined with the very absorption in the visible spectral range has made these molecules a very interesting class of molecules for nonlinear optical applications.

The article presents a new strategy, which is employed for microwave-induced multiple functionalization of the carbon nanotubes. The produced double functionalized single-walled nanotubes are shown to be extremely useful in several applications.

The article explains a new approach, which utilizes microwaves for the cycloaddition of aziridines to carbon nanotubes (CNTs). The microwave-assisted method is found to be extremely beneficial, as it increases the rate and the yields of the reactions.

Several synthetic protocols are employed to study the synthesis, characterization and photoinduced electron transfer in the single-wall carbon nanohorns (SWNHs). The analysis reveals that SWNHs often exhibit a continum of faradic and pseudocapacitive behavior, which is always accompanied by the quenching of the fluorescence of porphyrin in the conjugates.

Free and functionalized gold nanoparticles are synthesized by laser ablation of a gold metal plate immersed in dimethyl sulfoxide, acetonitrile, and tetrahydrofuran. Functionalized gold nanoparticles are synthesized in a one-step process solubility of the ligands in these solvents.

The multiphoton absorption properties of the axially substituted trtrapyrazinoteteaazaporphyrazinato complex, Pyz4TAPInCl are reported and interpreted. The noncolinear optical transmission of the complex and the excited states involved in the noncolinear absorption is determined at the frequency of the second harmonic generation of the Nd:YAG laser in the nanosecond time regime.

The value of the two photon absorption cross section which is found to be several orders of magnitude larger than the ones that are usually found for two photon absorbing systems excited from the ground state is calculated. The importance of an excited-state population for obtaining large nonlinear optical responses is demonstrated.