We have incorporated rhodamine into polyamide membranes by additive manufacture selective laser sintering technology. Incorporation into 0.5 cm2 membranes was conducted at different pH values and constant temperature of 25 oC. The amounts of incorporated dye were determined by a calibration curve, and analyses showed rhodamine incorporation in the order of 10-6 mol L-1. The absorption spectra of the solutions and membranes after rhodamine incorporation showed maximum absorption at 553 nm and a shoulder at 522 nm, which indicated that a dimer was formed. Photoluminescence presented maximum emission at 575 nm for the sample incorporated with rhodamine in acid pH. The membranes that were treated with acid presented shorter adsorption time and demanded 180 min to reach equilibrium, whereas the non-treated membrane and the membranes that were treated with base required 1440 min to reach equilibrium. Polyamide membrane has proven to be an excellent material for the incorporation of dyes and compounds for application as luminescent sensors.

Lanthanide ions have special light emission, which can occur through descending and ascending energy conversion. Ascending energy conversion is especially interesting for bioapplications because excitation in the infrared region does not excite biomolecules and therefore does not interfere in detection, not to mention that it penetrates deeper in the skin. Here, we synthesized yttrium and aluminum oxide doped with Yb3+and Er3+ions via the non-hydrolytic sol-gel methodology. The doped matrix was incorporated and dispersed over a polyamide membrane obtained by Additive Manufacturing. X-ray diffraction revealed that a mixture of yttrium aluminum monoclinic and garnet phases emerged. Upon excitation at 980 nm in the Yb3+ion, the Er3+ presented more intense emission as a function of the laser power, which favored red emission. The intensities of the bands corresponding to the 4S3/2 → 4I15/2 (563 nm) and 5F9/2 → 4I15/2 (660 nm) transitions involved the absorption of two photons. The oxide incorporated into the polyamide membrane presented the same behavior. After coating with polyetherimide, the latter system was resistant to 5.1 W laser, which paves the way for new applications.

Additive manufacture is an effective technology to produce complex macrostructures from polymers. Sol-gel is a chemical process that affords multifunctional materials by functionalization of different substrates. This work reports on the use of acrylonitrile-butadiene-styrene polymer (ABS) as starting material to obtain a substrate by additive manufacture. Coating of ABS by the sol-gel methodology generated a multifunctional material. Sols with and without phosphate ions were prepared from silicon and calcium alkoxide. Based on X-ray diffraction patterns, a calcium phosphate crystalline structure emerged on ABS after contact of the substrate with simulated body fluid. Infrared analysis revealed that the peaks of the functionalized substrate shifted, indicating that ABS interacted with the sol-gel coating. According to thermal analysis, the maximum decomposition temperature of the coated samples was 20 ºC higher as compared to non-coated ABS. Sol-gel and additive manufacture are important technologies to produce materials with applications in biological medium.

Over the last decades, the combination of different technologies to search for systems with new properties and features has brought various segments of biological and earth sciences together. Additive manufacturing, known as rapid prototyping, combined with the sol-gel methodology enables the production of novel systems with applications in many scientific fields. In this work, flexible polyamide membranes were obtained by additive manufacturing, functionalized by the sol-gel methodology, and incorporated with the coordination compound between Eu(III) and 1,10-phenanthroline. The presence of vibrations at 1100 cm-1 in the FTIR spectrum of the material, which is a band typical of the Si-O-Si group in the alkoxide employed during the process, confirmed the polyamide membrane functionalization. The thermogravimetric curve showed that a residue remained after heating at 700 ºC, which was attributed to SiO2. The membrane was highly luminescent, which confirmed incorporation of the Eu3+ compound into the material and pointed to the possible application of this system as a topical medication for the treatment of skin diseases.

Um novo material a base de poliamida revestida com fosfato de cálcio foi desenvolvido visando potencial aplicação como biomaterial. O revestimento foi obtido pelo método sol-gel e o fosfato de cálcio foi obtido após contato com solução de fluído corpóreo. A poliamida revestida (antes e depois de contado com fluído corpóreo) foi caracterizada através de análises termogravimétrica e térmica diferencial (TGA/DTA), calorimetria diferencial de varredura (DSC), microscopia eletrônica de varredura (SEM) e espectrometria de reflexão total atenuada no infravermelho com transformada de Fourier (ATR-FTIR). As caracterizações revelaram a formação de fosfato de cálcio com uma espessura menor que 3 µm, o que proporcionou um aumento no ponto de fusão além de melhorar a estabilidade térmica da poliamida. Após contato com o fluído corpóreo, as interações entre o revestimento e o substrato se mantiveram, e houve formação de fosfatos cristalinos e amorfos na superfície de poliamida.

A new type of material from polyamide coated with calcium phosphate was developed aiming to have potential application as biomaterial. Coating was obtained by the sol-gel method and calcium phosphate was obtained after contact with body fluid solution. The coated polyamide (before and after contact with body fluid solution) was characterized by thermogravimetric and differential thermal (TGA/DTA) analyses, differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). These characterizations revealed that the calcium phosphate coating has a thickness of less than 3 µm, which resulted in an increase in the melting point and improved the thermal stability of polyamide. After contact with body fluid, the interactions between the coating and the substrate remained, and there was formation of crystalline and amorphous phosphates on polyamide surface.

The aim of this work was to contribute to the creation of new ways of treating wastewater contaminated with Cr3+, based on solid-liquid adsorption. An adsorbent material was prepared by functionalization of kaolinite with glycerin biodiesel by-product. This material was tested for adsorption performed using a batch method, and results showed that inclusion of glycerin in the structure of kaolinite led to a significant increase in the capacity of Cr3+ adsorption. This contributes to the allocation of by-product of biodiesel and to the treatment of effluents from tanneries.

This work describes the hydrolytic sol-gel synthesis of silica particles prepared by a modified Stöber route, using the organofunctionalized alkoxide 3-methacryloxypropyl trimethoxysilane and tetraethylorthosilicate. The silica particles were obtained through basic catalysis from a mixture of precursor alkoxides, water, and isopropyl alcohol. Samples were prepared with change to the pre-hydrolysis and condensation time of tetraethylortosilicate, followed by addition of the organosilane 3-methacryloxypropyl trimethoxysilane. Eu3+ ions were added to the alkoxides mixture, in order to obtain structural information about the silica particles. The samples were centrifuged, washed with ethanol, and dried at 50 ºC. The xerogel was analyzed by thermogravimetric analysis, photoluminescence, transmission electron microscopy, and infrared spectroscopy. The photoluminescence spectra revealed Eu3+ lines characteristic of the ion 5D0 <img src="/img/revistas/mr/2011nahead/aop_0408-10_set.jpg" alt="" align="absmiddle"> 7F J (J = 0, 1, 2, 3, 4) transition. The thermogravimetric curve and infrared spectra confirmed the presence of the alkoxide organic group and water in the materials. Transmission electron microscopy showed spherical particles with varied size. The time of pre-hydrolysis and condensation as well as the addition of 3-methacryloxypropyl trimethoxysilane affect the final shape and size of the materials, so they can be used as control factors.

The sol-gel process is very effective for the preparation of new materials with potential applications in optics, sensors, catalyst supports, coatings, and specialty inorganic polymers that can be used as hosts for the accommodation of organic molecules. The low temperature employed in the process is the main advantage of this methodology. In this work, the europium (III) complex with 1,10-phenantroline was prepared, and this luminescent complex was incorporated into silica nanoparticles and films by the sol-gel process. The nanoparticles were obtained by the modified Stöber methodology. The films were obtained by the dip-coating technique, at different deposition rates and numbers of layers. The nanoparticles and films were characterized by photoluminescence, thermal analysis, and Raman and infrared spectroscopies. Characterization revealed that the europium (III) complex was not affected upon incorporation into the nanoparticles and films, opening a new field for the application of these materials.

O objetivo deste estudo foi demonstrar a sinterização pelo método sol-gel não-hidrolítico de um cimento de ionômero de vidro experimental (CIV) e avaliar sua biocompatibilidade em relação a um cimento de ionômero de vidro convencional (Vidrion R). Quatro tubos de polietileno contendo os cimentos testados foram implantados no dorso de 15 ratos, da seguinte maneira: GI - CIV Experimental e GII - CIV Convencional. A lateral do tubo foi considerada Grupo Controle. Os ratos foram sacrificados em 7, 21 e 42 dias pós-implantação para análise histopatológica. Uma escala de I a IV foi utilizada como sistema de score para graduar a reação inflamatória. Em relação à sinterização do CIV experimental, as análises termogravométrica e por difração de raio-x demonstraram a formação de material vítreo aos 110oC pelo método sol-gel. Para o teste de biocompatibilidade, os resultados mostraram uma reação inflamatória moderada para o GI (III), severa para o GII (IV) e branda para o Grupo Controle (II) aos 7 dias. Após 21 dias, GI apresentou uma reação branda (II); GII, moderada (III) e Grupo Controle, branda (II). Aos 42 dias, GI apresentou uma reação inflamatória branda/ausente (II a I), similar ao GII (II a I). O Grupo Controle demonstrou ausência de reação inflamatória (I). Concluiu-se que o CIV Experimental apresentou reação tecidual branda/ausente após 42 dias, sendo biocompatível quando testado em tecido conjuntivo de ratos.

The aims of this study were to demonstrate the synthesis of an experimental glass ionomer cement (GIC) by the non-hydrolytic sol-gel method and to evaluate its biocompatibility in comparison to a conventional glass ionomer cement (Vidrion R). Four polyethylene tubes containing the tested cements were implanted in the dorsal region of 15 rats, as follows: GI - experimental GIC and GII - conventional GIC. The external tube walls was considered the control group (CG). The rats were sacrificed 7, 21 and 42 days after implant placement for histopathological analysis. A four-point (I-IV) scoring system was used to graduate the inflammatory reaction. Regarding the experimental GIC sintherization, thermogravimetric and x-ray diffraction analysis demonstrated vitreous material formation at 110oC by the sol-gel method. For biocompatibility test, results showed a moderate chronic inflammatory reaction for GI (III), severe for GII (IV) and mild for CG (II) at 7 days. After 21 days, GI presented a mild reaction (II); GII, moderate (III) and CG, mild (II). At 42 days, GI showed a mild/absent inflammatory reaction (II to I), similar to GII (II to I). CG presented absence of chronic inflammatory reaction (I). It was concluded that the experimental GIC presented mild/absent tissue reaction after 42 days, being biocompatible when tested in the connective tissue of rats.

Glass ionomer cements are widely employed in dentistry due to their physical, biological and mainly anti-caries properties. Glass ionomers consist of an aluminosilicate glass matrix modified with other elements, and they contain large quantities of fluorine. In this study, we report on the preparation of calcium-fluoroaluminosilicate glasses by a nonhydrolytic sol-gel route as an alternative approach to obtaining alumina-silica matrices. The glass powders were prepared via the non-hydrolytic sol-gel method, by mixing AlCl3, SiCl4, CaF2, AlF3, NaF, and AlPO4. The powders were studied by thermal analysis (TG/DTA/DSC), photoluminescence (PL), nuclear magnetic resonance (NMR27Al-29Si), and X ray diffraction (XRD). TG/DTA/DSC analyses revealed a constant mass loss due to structural changes during the heating process, which was confirmed by NMR and PL. A stable aluminosilicate matrix with potential future application as a glass ionomer base was obtained.

TiO2 films have various applications, among them solar cells and photodegradation of pollutants. In this study, we investigated TiO2 films functionalized with the organic dye cyanidin extracted from black mulberry (Morus nigra). The TiO2 was functionalized by the sol-gel method and the film was deposited on glass substrates by dip-coating. Our aim was to investigate the interaction between the semiconductor and the dye, as well as the influence of the velocity and number of deposits on the characteristics of the film. Using ultraviolet-visible spectroscopy, we observed a shift from the maximum absorption band at 545 nm for the dye’s ethanol solution to 595 nm for the film, indicating interaction of the cyanidin with the TiO2. The absorption spectra in the infrared region of the functionalized TiO2 particles showed bands characteristic of the oxide and indicated their interaction with the dye. Using profilometry and m-line techniques, we found that the films presented thicknesses in the order of 100 nm. A SEM analysis confirmed the high density of the films.

In this work titanium sol was prepared from tetraethylorthotitanate (TEOT) in ethanol, stabilized with beta-diketonate 2,4 pentanedione in molar ratio 1:1 homogenized by magnetic stirring, europium ion was add as structural probe. The xerogels were heat treated at 500, 750 and 1000 °C and the characterization was realized by x-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA/DSC) and photoluminescence (PL). The excitation spectra of Eu (III) ion present maximum in 394 nm correspondent to 5L6 level and emission spectra present bands characteristic transitions arising from the 5 D0 -> 7F J (J = 0, 1, 2, 3, 4) manifolds to samples treat at 500 and 750 °C. The Eu (III) emission disappear, when heated at 1000 °C, probably due to phase transition anatase to rutile and migrations of ions to the external surface that was proved by x-ray diffraction, transmission electronic microscopy and the thermogravimetric analyses of xerogels.

In this work we report some aspects of the chemistry involved in the preparation of modified silicon oxide by the sol-gel process. Europium III compounds were used as luminescent probe. An organic-inorganic hybrid was obtained by hydrolysis of tetraethylorthosilicate (TEOS) and 3-aminopropyltriethoxysilane (APTS). The Eu III compounds were added in different ways. In the first, silica was prepared in the presence of Eu III, and in the second, Eu III was added on the silica surface. These materials were studied by luminescence, infrared spectroscopy and termogravimetric analysis. The results obtained for the hybrid material show different behavior for Eu III emission, which could be excited by the antenna effect and the influence of the surrounding in the luminescence quenching. The thermogravimetric data present different mass loss in samples to range temperature 50 - 150 °C. Thermogravimetric and infrared spectra showed that inorganic polymers incorporated the organic part.