Search

Regarding metals adsorption from aqueous solutions, nanocellulose emerges as a potential material, due to the many functionalization possibilities and enhanced surface contact area (nanostructured nature). In the present work, sulfated and carboxylated nanocellulose samples were obtained through sulfuric acid hydrolysis (S-CNC) and oxidation by TEMPO (CNF). The obtained nanofibers were characterized through multiple techniques, which XRD data indicated the presence of α-cellulose crystals, with crystallinity indexes equal to 72.3% (S-CNC) and 69.3% (CNF). Expressive morphological differences were revealed, whiskers particles for S-CNC, and elongated nanofibrils for CNF, with average thickness of 9.99 and 5.61 nm, respectively. The desired functionalization with carboxylate groups was evidenced based on FTIR data (CNF). A significant and homogeneous presence of sulfur was evidenced through SEM/EDS (S-CNC). The synthesized nanofibers were next applied to cobalt (Co+2) adsorption from aqueous solutions at room temperature. On both cases, expressive maximum cobalt recoveries have been achieved, 90% (CNF) and 87% (S-CNC), for contact times higher than 30 and 45 min, respectively. The adsorptive capacities evaluated through ICP-OES from liquid phase data (87 mg g−1 S-CNC; 90 mg g−1 CNF) were both significantly higher than the values determined through LA-ICP-MS (10.5 mg Co g−1 S-CNC; 31.5 mg Co g−1 CNF).

Made available in DSpace on 2021-06-25T11:03:45Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Nowadays, flexible organic electronics are under intense investigation for environmentally friendly and biocompatible applications. One of the main components of electronic devices is the substrate, which gives support for building devices. There is great interest in the scientific community for the development of biocompatible and biodegradable substrates for the manufacture of these kinds of devices, aiming at technological and medical applications. In this work, we produced a flexible and transparent biosubstrate based on a gellan gum polymer by a solvent casting method to manufacture flexible organic light-emitting diodes (FOLEDs). The gellan substrate exhibited optical transparency of about 78% at 550 nm and 80% at 900 nm. In addition, the optimized indium tin oxide (ITO)/SiO2-coated gellan substrate exhibited a resistivity of 2.8 × 10-4 ω·cm and a sheet resistance of 11.2 ω/sq. These values are better or equal to those found in the literature for similar biosubstrates. Finally, the fabricated FOLEDs exhibited a maximum luminance of about 2327 cd/m2 and the current efficiency reached a maximum value of 2.9 cd/A. These characteristics reveal that this biosubstrate has interesting potential for applications in flexible green electronics, mainly due to its biocompatible properties and the results obtained by the developed FOLEDs. Grupo de Nanociência e Nanotecnologia (NANO) Departamento de Física Universidade Federal de Juiz de Fora (UFJF) Laboratório de Biopolímeros e Biomateriais (BIOPOLMAT) Departamento de Biotecnologia Universidade de Araraquara (UNIARA) Laboratório de Optoeletrônica Molecular (LOEM) Departamento de Física Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio) Departamento de Química Pontifícia Universidade Católica do Rio de Janeiro (PUC-Rio) Instituto de Química Universidade Estatual Paulista Júlio de Mesquita Filho (UNESP) Instituto de Química Universidade Estatual Paulista Júlio de Mesquita Filho (UNESP)

Monolayers of molybdenum disulfide are of vital importance in the fabrication of optical and nanoelectronic devices. The development of thin and low-cost devices has increased the demand for synthe...

Fabrication of well-aligned arrays of microfluidic channels is very challenging using conventional microfabrication processes. On the other hand, nature is unique in creating complex hierarchical architectures. For instance, wood-derived materials present well-aligned microchannels that offer the possibility to add new functionalities to biological templates, such as high conductivity necessary for electric and electrochemical devices. However, one of the challenges is to address electrical properties without clogging cellulose-based channels. In this work, a new regioselective coating method is reported to prepare three-dimensional functional conductive structures using bamboo as a bio-template. Silver ink was flowed inside bamboo vascular bundles and excess of the material was removed to prepare ultra-highly conductive coatings that did not block its channels. The conductivity of the hollow channels was 9.3 (±4.0) × 105 S m−1, which is the highest value reported for cellulose-based ordered materials. Such remarkable feature enabled the fabrication of unprecedented electrical and electrochemical devices. For example, three-dimensional circuits, microfluidic heaters and fully integrated nanostructured carbon-based electrochemical cells were fabricated using bamboo with fast and low-cost prototyping processes. Moreover, the present work opens a plethora of possibilities to incorporate conductors, semi-conductors and insulating materials for the next generation of electric and electrochemical “bambootronic” bio-devices.

Hybrid fillers have triggered significant research in the field of polymer-based composites because they offer a range of properties that cannot be achieved by a single filler. Here a novel hybrid filler comprised of titanate nanotubes (TTNT) and Y2W3O12, a thermomiotic ceramic, was incorporated into a high density polyethylene matrix (HDPE) at an extremely low concentration (2 mass %). The influence of TTNT/Y2W3O12 mass ratio (1:1, 1:2 and 2:1), surface treatment of hybrid filler with cetyltrimethylammonium bromide (CTAB) and chemical modification of HDPE with polyethylene-grafted maleic anhydride (PE-g-MA), on the resulting mechanical and thermal properties of HDPE-based composites was investigated. The largest increase (25%) in Young’s modulus and the greatest reduction (23%) in coefficient of thermal expansion (CTE) of HDPE was achieved for 2:1 TTNT/Y2W3O12 mass ratio, without significant alteration of thermal degradation beginning or thermal conductivity of HDPE. At this optimum TTNT/Y2W3O12 mass ratio, CTAB treatment of fillers was more efficient than PE-g-MA modification of matrix promoting a better dispersion of TTNT/Y2W3O12, leading to an increase of 34% in composite stiffness and a CTE reduction of 18%, although both treatments improved hybrid filler-matrix interfaces, as judged by a rise of 6% in yield strength.

Lignocellulose-based bamboo powder was used as pristine support to immobilize two different biocatalysts: Candida Antarctica lipase B and Rhizomucor miehei lipase. Both, IB-CalB and IB-RM, physically absorbed on bamboo carrier presented considerable recycling efficiency, up to 10 consecutive cycles, in batch mode for the ethyl palmitate synthesis with conversion about 50 and 80 %, respectively. The kinetic resolution of racemic-1-phenylethanol mediated by IB-CalB showed a higher conversion against the IB-RM in batch mode. IB-CalB packed into a glass column reactor was used to carry on a kinetic resolution in flow mode regime with an intensification conversion up to 45 % with 99 % e.e. The easy and low-cost method of the lipase adsorption without pre-treatment of the carrier can be promising for industrial biocatalytic transformation and immobilization strategy.

The improvement of photocatalytic activity of TiO2-based nanomaterials is widely investigated due to the tentative of their industrialization as environmental photocatalysts and their inherently low solar spectrum sensitivity and rapid recombination of charge carriers. Coupling of oxygen-based bidentate diketone to nanocrystalline TiO2 represents a potential alternative for improving the holdbacks. Formation of TiO2-acetylacetone charge transfer complex (CTC) by sol-gel route results in a hybrid semiconductor material with photodegradation activity against toxic NOx gas. In this research, the influence of the chelating agent acetylacetone (ACAC) content on the CTC photocatalytic efficiency under visible light was evaluated. A high content of ACAC in the CTC is not a decisive factor for efficiency of photocatalytic reactions. In fact, the highest efficiency for NOx degradation (close to 100%, during 1 h of visible light exposure) was reported for the material calcined in air at 300 &deg, C with the content of strongly bonded acetylacetone not higher than 3 wt.%. Higher calcination temperature (400 &deg, C) left TiO2 almost completely depleted in ACAC, while at the highest applied temperature (550 &deg, C) a portion of anatase was transformed into rutile and the sample is free of ACAC. The analyses pointed out that superoxide anion radical (O2&minus, ) plays an active role in photo-oxidation of NOx. Our findings indicate that this CTC has both high visible light spectral sensitivity and photocatalytic efficiency.

A new experimental set-up permitting scale-up and serial internal numbering-up of meso- and micro photocatalytic systems, respectively, was developed to compare their photodegradation efficiency, by using of a commercially avaliable TiO2 (P25), against Rhodamine B (RB) and Methylene Blue (MB) under UV irradiation in water. A circular photocatalytic unit constituted of TiO2 embedded into PDMS was the basic unit of the meso and microchemical reactors. Different volumetric capacity, from 10 μL to 1000 μL, and different flow rates (0.05–1.0 mL min−1) were evaluated to understand the best approach to design a more efficient fixed bed photoreactor for photocatalytic degradation. The multi-photocatalytic microreactor system with the best performace, built-up by plugging six modular microreactor plates (M6), was tested for photooxidition of phenol under UV irradiation, as well. P25 catalyst showed different photodegradation efficiency depending on the photocatalytic meso- and microreactor design and flow parameters. The photocatalytic efficiency for the meso- and microdevices was evaluated by figure-of-merit electrical energy per order (EEO) and apparent quantum yield. The numbered-up M6 system had a lower electrical energy consumption compared with others. The microfluidic device M6 was able to achieve 97% of photodegradation of MB and RB (1.2 10−5 mol L−1) in 1 h compared to 96% conversion of the best mesoreactor in 16 h, while reached a total mineralization of phenol (1.2 10−4 mol L−1) to CO2 and H2O in 6 h.

Made available in DSpace on 2020-12-12T02:23:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2019-01-01 A new biopolymer obtained from onion pulp (Allium cepa L.) was employed to produce a sustainable substrate for flexible organic light-emitting diodes (FOLEDs). Indium tin oxide (ITO) and SiO2 thin films were deposited by rf-magnetron sputtering onto these biosubstrates to obtain flexible, transparent, and conductive anodes, on top of which FOLEDs were produced. This new biomaterial exhibits an optical transparency of 63% at 550 nm. ITO films were optimized by varying rf power during deposition onto the biopolymers, and their electrical properties are comparable to the those of ITO grown on top of rigid substrates: a carrier concentration of -3.63 × 1021 cm-3 and carrier mobility of 7.72 cm2 V-1 s-1 for the optimized film. Consequently, the sheet resistance and resistivity of this ITO film were 8.92 ω sq-1 and 2.23 × 10-4 ω cm, respectively, hence allowing the production of FOLEDs. The A. cepa L. based FOLED was fabricated using CuPc, β-NPB, and Alq3 as organic layers, and it exhibited a maximum luminance of about 2062 cd m-2 at 16.6 V. The current efficiency reached a maximum value of 2.1 cd A-1 at 85.3 mA cm-2. The obtained results suggest the possibility to use these substrates for innovative biocompatible applications in optoelectronics, such as photodynamic therapy. Grupo de Nanociência e Nanotecnologia (NANO) Departamento de Física Universidade Federal de Juiz de Fora (UFJF) Laboratório de Biopolímeros e Biomateriais (BIOPOLMAT) Departamento de Química Universidade de Araraquara (UNIARA) Instituto de Física de São Carlos Universidade de São Paulo (USP) Instituto de Química Universidade Estatual Paulista Júlio de Mesquita Filho (UNESP) BioSmart Nanotechnology Laboratório de Optoeletrônica Molecular (LOEM) Departamento de Física Pontifícia Universidade Católica Do Rio de Janeiro (PUC-Rio) Departamento de Química Pontifícia Universidade Católica Do Rio de Janeiro (PUC-Rio) Instituto de Química Universidade Estatual Paulista Júlio de Mesquita Filho (UNESP)

The fabrication of a new copper-functionalized lignocellulosic microreactor (Cu-LμR) from bamboo culms is herein described together with its operation to perform a copper(I)-catalyzed 1,3-dipolar c...

An (S)-5-(pyrrolidin-2-yl)-1H-tetrazole organocatalyst has been prepared in the form of a monolithic column through the radical copolymerization of a styryl-functionalized pyrrolidinyl-tetrazole derivative, styrene and divinylbenzene in the presence of porogens (dodecanol and toluene). The activity of the monolithic pyrrolidinyl-tetrazole organocatalyst (triturated polymer) has been initially tested under batch conditions using the asymmetric aldol reaction of cyclohexanone and p-nitrobenzaldehyde as the benchmark. A prerequisite of the study has been the utilization of the eco-friendly water–ethanol mixture as the solvent. After having established the high efficiency and recyclability of the catalyst under these conditions, the effect of the flow regime has been evaluated by fabricating the corresponding monolithic microreactor (pressure-resistant stainless steel column). It has been demonstrated by a brief substrate scope study that the flow regime contributes to preserve the activity of the pyrrolidinyl-tetrazole catalyst over time (5 days on stream) with an almost twofold increase in productivity moving from batch to flow conditions. An added value of the flow procedure has been the optimization of a suitable 2D instrumental setup for simultaneous flow reaction and online flow-injection analysis.

Silver nanoparticles (Ag-NPs) have attracted attention as a promising nano-filler material for reinforcement and anti-bacterial effect in polymers and composites. In this work bamboo samples, Dendrocalamus Giganteus Munro, were impregnated using a colloidal solution of homemade Ag-NPs with the goal of improving its resistance to attacks by fungi. X-ray microtomography (μCT) was performed to investigate the 3D distribution of Ag-NPs within the biological matrix. 3D image reconstruction showed silver clusters distributed within the parenchymatic tissue. Quantitative information of the Ag-NPs agglomerate population was computed. Ag-NPs were characterized by UV-VIS, SERS, ICP-MS, TSEM, DLS and zeta potential analysis. The antimicrobial activity of homemade and commercial citrate-capped silver nanoparticles was evaluated against the Aspergillus niger fungus. Homemade nanoparticles (NP-01), presenting the smallest diameter (14.3 ± 3.6 nm), and the highest particle concentration (1.25 × 1011 particles per mL) were able to inhibit 53% of Aspergillus niger growth in a concentration of 2.00 mg L−1. Both engineered biocomposite material and untreated specimens were exposed to air and humidity. After five months the treated samples were free of fungal colonies, while colonization by the fungal hyphae was present on untreated bamboo specimens.

Astronomical observations towards star-forming regions have revealed the presence of molecules with the N-O bond such as NO, N2O, and HNO. These species are considered potential precursors of prebiotic molecules. Thus, understanding nitrogen and oxygen chemistry may help us to better understand the origin and evolution of prebiotic molecules in space. However, species with the N-O bond are poorly studied and laboratory works on the effects induced on them by solar wind and galactic cosmic rays are still scarce. For this, we wanted to study the effects of ion bombardment on molecules with the N-O bond. We focus here on N2O ices and NO2:N2O4 = 1:1 ice mixtures (at 16 and 50/60 K) irradiated with 200 keV protons. Infrared transmission spectroscopy (8000-500 cm-1; 1.25-20 μm) was used to analyse the samples. Irradiation of N2O ices and NO2:N2O4 ice mixtures produces comparable effects independent of the irradiation temperature, NO being the main product. Moreover, we show that the maximum amount of N2O and N2O4 destroyed by irradiation, at the highest dose reached in our experiments, is equal to about 98 and 70 {{ per cent}}, respectively. The dose range covered in the experiments has been compared with the astrophysical time-scale of surface processing in space, showing that irradiation of N2O and NO2:N2O4 mixtures can produce, within 105-108 yr, amounts of solid NO ice detectable towards star-forming regions by the James Webb Space Telescope.

The application of the oxidative system composed of a heterogeneous triazolium pre-catalyst, iron(ii) phthalocyanine and air is described for the selective conversion of 5-hydroxymethylfurfural (HMF) into the added-value 5-hydroxymethyl-2-furancarboxylic acid (HMFCA). The disclosed one-pot two-step procedure involved sequential oxidative esterifications of HMF to afford a polyester oligomer having hydroxyl and carboxyl terminal groups (Mw = 389-1258), which in turn was hydrolyzed by a supported base (Ambersep 900 OH) to yield HMFCA in 87% overall yield. The same strategy was adopted for the effective synthesis of ester and amide derivatives of HMFCA by nucleophilic depolymerization of the oligomeric intermediate with methanol and butylamine, respectively. The utilization of the disclosed oxidative system for the direct conversion of HMF and furfural into their corresponding ester, amide, and thioester derivatives is also reported.

The efficiency of photo-oxidation of pollutants catalysed by semiconductors is still limited for real-world applications due to several drawbacks, such as a) insufficient absorption of visible radiation, which predominates in solar spectrum, b) rapid free electron to hole recombination, c) small surface area, built from equilibrium crystallographic facets with low adsorption capacities and d) photo-corrosion. The present study disclosures new mesoporous heterostructures, built from exfoliated lepidocrocite-like ferrititanates and TiO2 (anatase)-acetylacetone charge transfer complex, capable of reducing free electron-to-hole recombination rate through a robust charge separation and sensitive to the visible light spectrum. The synthesis route is based on soft-chemistry and low temperature calcination at 300 °C. Two different partially pillarized heterostructures, denoted as HM-1 and HM-2, have been synthesized. It was observed that the heterostructure HM-1 was four times more active toward photocatalytic degradation of NO gas in comparison to the benchmark photocatalytic material P25. The lower activity of the heterostructure HM-2, comparable to that of P-25, was attributed to the high value of Urbach energy that indicates high number of defect sites within energy band-gap of the constituent semiconductor components. [Ti] anatase/[Ti] ferrititanate mol ratio might also play a role in photocatalytic efficiency. © 2018 Elsevier B.V. Published version: [https://hdl.handle.net/21.15107/rcub_dais_3692] This is the peer reviewed version of the following article: Habran, Margarita, Patricia I. Pontón, Lidija Mančić, Omar Pandoli, Klaus Krambrock, Marcelo Eduardo Huguenin Maia da Costa, Sonia Letichevsky, Antonio Mario Leal Martins Costa, Edisson Jr Morgado, and Bojan A. Marinković. 2018. “Visible Light Sensitive Mesoporous Nanohybrids of Lepidocrocite-like Ferrititanate Coupled to a Charge Transfer Complex: Synthesis, Characterization and Photocatalytic Degradation of NO.” Journal of Photochemistry and Photobiology A: Chemistry 365: 133–44. [https://doi.org/10.1016/j.jphotochem.2018.07.038]

The degradation processes of tris(8-hydroxyquinoline) (Alq3) and tris(dibenzoylmethane) mono(1,10-phenanthroline)europium(III) (Eu(dbm)3(phen)) thin films are investigated by the use of AFM, photoluminescence and SPR spectroscopy. The plasmonic sensors are operated both in air and nitrogen environments, where they are irradiated with controlled doses of UVA radiation. AFM results don’t reveal the formation of heterogeneous phases and crystallization under air exposure. The organic thin films change their refractive index under both types of exposure and act as a protective layer against oxidation for the SiO2/MPTS/metal interface of the plasmonic sensors. SPR measurements reveal a strict correlation between the refractive index increase and quenching of the photoluminescence of the organic thin films. The results are promising for the development of compact plasmonic UVA dosimeters in the surface plasmon coupled emission configuration (SPCE) with lanthanide β-diketonate complex materials (patent pending).

Ligand-free carbynoid-encapsulated gold nanocomposites (Au@Carbynoid NCs) with blue-shifted localized surface plasmon resonance (LSPR) have been synthesized by CO2 recycling induced by pulsed laser ablation (PLA) of a solid gold target in aqueous solution with NaOH at pH 7.0. High Resolution Transmission Electron Microscopy (HRTEM) images at not destructive acceleration voltage of 80 kV revealed carbynoid nanocrystals around the gold core, associated to the intense bond length alternation (BLA) Raman mode of the carbon atomic wires (CAWs), centered at 2124 cm−1, observed in the Surface Enhanced Raman Scattering (SERS) spectra. It was verified that interlinking process with sp to sp2 conversion of the CAWs is induced both by high acceleration voltage in HRTEM and high irradiance of the excitation beam used in SERS measurements. Post synthesis mixing of Pluronic-F127 copolymer with pre-synthesized Au@Carbynoid NCs allows the formation of a fully biocompatible colloidal solution of Au@Carbynoid/Copolymer NCs. SERS investigation highlights that the Raman band of the BLA mode can be used as efficient Raman tag to monitor the functionalization of the NCs with the copolymer. The biocompatibility of the NCs was demonstrated performing a study of cytotoxicity using human skin fibroblasts. As proof of principle, it was demonstrated that the photodynamic activity of the bifunctional Au@Carbynoid/PF127 NCs in the presence of chlorin e6 (Ce6) drug can be enhanced inducing the aggregation state of the colloidal suspension. The stability of the colloidal dispersions of Au@Carbynoid NCs functionalized with Pluronic-F127 is verified after centrifugation in PBS (0.15 mol L−1 NaCl) solutions, confirming the possibility to use the green carbynoid based NCs as drug-carrier in biological applications.

Efficient methods for the synthesis of layered structure nanomaterials (nanosheets), their complete exfoliation (delamination) into the layers of atomic thickness and design of organic–inorganic nanohybrids present important stages toward development of improved polymer-based nanocomposites and pillared heterostructures with potential application in purification technologies such as photocatalysis. A rapid and efficient exfoliation process of protonated layered ferrititanates with lepidocrocite-like structure and formation of organic–inorganic nanohybrids is performed starting from the nanosheets composed of only a few host layers and nanometric lateral dimensions using quaternary ammonium compounds. These nanosheets are initially synthesized from a highly abundant precursor through an alkaline hydrothermal route. We demonstrated that dimethyldioctadecylammonium cations strongly interact with the exfoliated single host layers (0.75 nm thick) providing thermal stability (~500 °C) to the as-prepared organic–inorganic nanohybrid over the temperature range commonly applied for the processing of thermoplastic nanocomposites. Keywords: Layered structure, Nanosheet, Exfoliation, Small-angle X-ray scattering, Organic–inorganic nanohybrid, Thermal stability

To increase the durability of bamboo it is important to find an easy method to fill the micro and meso structure of the biological matrix using a nanostructural material with an anti-fungical activity. A colloidal solution of silver nanoparticle (Ag-NPs) is a dispersion of metal nanoparticle in water with a diameter between 5-100 nm. Even if the biological mechanism is not completly understood yet, Ag-NPs show a satisfactory bactericidal and antifungical activity. We present a simple and rapid production of Ag-NPs made by a sol-gel synthesis in flow mode by means of microreactor tecnology through a chemical reduction of AgNO3 with NaBH4 in presence of two different organic ligands: sodium/potassium tartrate and trisodium citrate. The synthesis of Ag-NPs in continuous flow compared to the batch technique allowed to reduce the time of synthesis, facilitating the reproducibility of the process and consequently obtaining NPs with more uniform physical and chemical characteristics. The microorganisms of the genus Aspergillus were used for the microbiological tests. The effect of different Ag-NPs on microbial growth was observed daily. In particular, it was shown that the response of the fungus is inversely proportional to the size of the nanoparticles, cell growth is disrupt depending on the proportion between silver and organic ligand and microbialstatic effect, especially in relation to sporulation stage was also observed.

Gentamicin is an antibiotic indicated to treat mastitis in dairy cattle and for the treatment of bacterial resistance in the context of hospital infections. The effect caused by gentamicin on the optical properties of gold nanoparticles aqueous dispersions were used to develop quantitative methods to determine this antibiotic. Two different aqueous dispersions, one containing spherical Au nanoparticles (AuNPs) and the other containing Au nanorods (AuNRs), had their conditions adjusted to enable a stable and sensitive response towards gentamicin. The use of AuNPs, with measurement at 681 nm of the rising coupling plasmon band, enabled a limit of detection (LOD) of 0.4 ng mL − 1 (0.02 ng absolute LOD), ten times lower than the one achieved by measuring the decreasing of the longitudinal surface plasmon resonance band (at 662 nm). The linear analytical response of AuNPs measured at 681 nm did not require rationing of signal values to correct for linearity. Stability of the analytical response resulted in intermediary precision below 2%. No significant interference was imposed by excipients traditionally present in injectable solutions for veterinary use. Percent recoveries obtained in such formulations were between 94.5 and 98.2% regardless the existence of any difference in the proportion of the compounds known as gentamicin (C 1 , C 1a and C 2 ) in standard and in the samples. The method requires no derivatization with toxic reagents as usually is required in other spectroscopic approaches.

A novel micromixer concept for generation of concentration gradients, inspired by a Chinese design, the traditional Chinese knot “中国结”, which features a core mesh structure allowing for a very compact design, is presented. The new concept has been designed using modern computer-aided design (CAD) and computational fluid dynamics (CFD) simulation software and validated by performing multiple experiments. The final design is found to be significantly more compact than conventional ones and allows the use of up to 15 outlet channels.

Colloidal suspensions of oxocarbon-encapsulated gold nanoparticles have been synthesized in a one-step procedure by pulsed-laser ablation (PLA) at 532 nm of a solid gold target placed in aqueous solution containing CO2 absorbers, but without any stabilizing agent. Multi-wavelength surface enhanced Raman spectroscopy allows the identification of adsorbed amorphous carbon and graphite, Au-carbonyl, Au coordinated CO2-derived bicarbonates/carbonates and hydroxyl groups around the AuNPs core. Scanning electron microscopy, energy dispersive x-ray analysis and high resolution transmission electron microscopy highlight the organic shell structure around the crystalline metal core. The stability of the colloidal solution of nanocomposites (NCs) seems to be driven by solvation forces and is achieved only in neutral or basic pH using monovalent hydroxide counter-ions (NaOH, KOH). The NCs are characterized by a blue shift of the localized surface plasmon resonance (LSPR) band typical of metal-ligand stabilization by terminal ?-back bonding, attributed to a core charging effect caused by Au-carbonyls. Total organic carbon measurements detect the final content of organic carbon in the colloidal solution of NCs that is about six times higher than the value of the water solution used to perform PLA. The colloidal dispersions of NCs are stable for months and are applied as analytical probes in amino glycoside antibiotic LSPR based sensing.

We present prototyping of meso- and microfluidic photocatalytic devices, functionalized through incorporation of TiO2 nanoparticles in polydimethylsiloxane (PDMS), and comparison of their efficiencies for the degradation of rhodamine B (10−5 mol/L). The prototyping of the photocatalytic devices involves simple and low-cost procedures, which includes microchannels fabrication on PDMS, deposition and impregnation of TiO2 on PDMS, and, finally, plugging on the individual parts. For the microfluidic device with 13 μL internal volume, photocatalytic TiO2–PDMS composite was sealed by another PDMS component activated by O2 plasma (PDMS–TiO2–PDMS). For the mesofluidic device, a homemade polyetheretherketone (PEEK) flow cell with 800 μL internal volume was screwed on a steel support with a glass slide and the photocatalytic composite. The photocatalytic activities of the devices were evaluated using two different pumping flow systems: a peristaltic pump and a syringe pump, both at 0.05 mL/min under the action of 3...

National Program on Key Basic Research Project (973 Program) [2010CB933901]; National Natural Science Foundation of China [51102258, 20803040, 81028009, 31170961]; Chinese Academy of Sciences [2011T2J06]; New Century Excellent Talents of the Ministry of Education of China [NCET-08-0350]; Zhejiang Provincial Natural Science Foundation [LY12H11011]

This paper presents a theoretical analysis of a surface plasmon resonance sensor coupled to a periodic array of spherical gold nanoparticles (AuNps). The sensor is in the Kretschmann configuration and composed by five layers: prism, thin gold film, dielectric insulator, array of AuNps and air. The AuNps layer is modeled with an effective permittivity by the Maxwell-Garnett mixing formula, and the wave propagation is analyzed using a generalized reflection coefficient. The results are presented in terms of reflectivity and modal field distributions for different thickness of the layers and geometry of the AuNps array.

The incidence of hospital infections caused by the fungus Candida albicans has increased substantially in the past decades. Specific tests for the diagnosis of sepsis due to Candida albicans have high cost and require a long time to obtain results. Given this situation and considering the need for constant search for alternatives in the diagnosis of septicemia by Candida albicans, in this work was developed and evaluated a new sensing platform for an optical immunosensor based on localized surface plasmon resonance. The sensing platform corresponds to a glass slide with nanoparticles of silver adhered on its surface and functionalized with monoclonal anti-candida antibodies of the immunoglobulins class. Cysteine molecules were used as ligand in the antibodies functionalization process and glycine as blockers of non-functionalized sites of the platform. On the preparation of the sensing platform, different concentrations of antibodies were explored. In the evaluation of the platform as a Candida albicans antigens sensor, the identification of different antigen concentrations was demonstrated. The results show the system ability to identify Candida albicans antigen concentrations greater than 50ng/mL, indicating the possibility of the use of the platform as immunosensor for Candida.

A photocatalytic microreactor is defined as a microfluidic device, which is integrated with a photocatalytic coating of TiO2 deposited on the inner surface of microchannels. This device is capable of degradation of organic dye solution in water in a continuous flow under the action of ultraviolet light. The objectives of this work were to present a rapid and economically viable approach for the prototyping photocatalytic microfluidic devices and to evaluate their photodegradation capability for organic dyes by ultraviolet-visible spectrophotometry. Prototyping of polydimethylsiloxane PDMS/TiO2/glass microreactors includes several procedures such as mold preparation, microchannel confection on PDMS surface, deposition of TiO2 on these microchannels, O2 plasma treatment of PDMS/TiO2 and glass surface for sealing these two parts. The efficiency of the photocatalytic microreactors was evaluated by fluxing two organic dye solutions, rhodamine B and methylene blue, with different flow rates of between 2 and 4 mL h-1. When the flow rate at 2 mL h-1was applied, discoloration of ~ 65% was achieved for both dye solutions, while PDMS/glass microchannels, without TiO2 film, demonstrated much lower discoloration of between 24 and 42% for rhodamine B and methylene blue, respectively. This confirmed that TiO2 was successfully deposited onto PDMS microchannels.

[reaction: see text] The tunable interconversion between two highly ordered supramolecular motifs (G-quartet K(+)-templated column and G-ribbon) of a lipophilic guanosine derivative fueled by cation complexation and release in a cryptand [2.2.2] containing guanosine solution is reported. The process is controlled by the sequential addition of acid and base.

The activity and stability under flow conditions of covalently and non-covalently silica supported proline and proline-like organocatalysts is herein described. The slow aldol reaction of cyclohexanone with p-nitro benzaldehyde and the fast α-amination of isovaleraldehyde with dibenzyl azodicarboxylate have been selected as model reactions for this study. Prospects and limitations of the disclosed continuous-flow organocatalytic approach are widely discussed.

Herein we report the chemical reduction of silver ions incorporated into chiral supramolecular nanostructures by NaBH(4) in buffered (basic) and unbuffered conditions. In situ self-assembly of guanosine 5'-monophosphate (5'-GMP) templated by Ag(I) and generation of silver nanoparticles (NPs) were continuously monitored by CD and UV-Vis spectroscopy measurements. 5'-GMP has been identified as an efficient chiral organic ligand to complex silver ions into a hierarchical helical nanostructure and is a useful capping agent for stabilizing silver NPs with a size diameter lower than 20 nm. The observation of opposite signed bands in the CD spectra of Ag(I)/5'-GMP complexes at different pH has suggested the existence of opposite-handed supramolecular helical structures depending on pH. Both helical supramolecular structures induce chirality in the silver NPs during their growth of the same handedness as shown by the CD signals in the plasmon resonance band.

A unique, sensitive, and highly specific fluoroimmunoassay system for antigen detection using gold and quantum dot nanoparticles has been developed. The assay is based on the fluorescence quenching of quantum dots caused by gold nanoparticles coated with antibody. To demonstrate its analytical capabilities, the CdTe quantum dots were coated with anti-HBsAg monoclonal antibodies (QDs-MAb1) and gold nanoparticles coated with another anti-HBsAg monoclonal antibodies (GNPs-MAb2) which specifically bound with HBsAg could sandwich the HBsAg captured by the immunoreactions. The sandwich-type immunocomplex was formed and the fluorescence intensity of quantum dots was measured. The results showed that the fluorescence intensity of quantum dots at 570 nm was negative linear proportional to the HBsAg concentration logarithm, and the limit of detection of the HBsAg was 0.928 ng/mL. This new system can be extended to detect target molecules with matched antibodies and has broad potential applications in immunoassay and disease diagnosis.

Template-driven strategy is widely explored for the synthesis of nano/micro materials. Of all the templates studied, naturally occurring biological systems such as proteins, viruses and bacteria have attracted more attention due to the prolific sources and complex structural diversities. Herein, we report a simple bacteria templated synthesis of silver microspheres over a bottom-up controlled route. These as-prepared silver microspheres not only have narrow size distribution but possess hollow and porous structures. Surface enhanced Raman scattering (SERS) experiments using 2-mercaptopyridine (2-Mpy) as probing molecules show that these hollow porous microspheres can act as excellent substrate for ultrasensitive detecting. The detection limit is as low as 10−15 M and the enhancement factor reaches to 1011. Compared with other conventional SERS substrates, the reproducible, high sensitive and cost-effective Ag microspheres could become an ideal substrate choice for practical SERS application.

Aloe Vera-conjugated Ag nanoparticles ( AgNPs@AV hybrids) are synthesized in large quantities by reducing silver nitrate with Aloe Vera pulp extract at room temperature. TEM image reveals that these NPs are predominantly spherical with an average of 25 nm in diameter. The crystal structure of AgNPs@AV is determined by XRD. The cytotoxicity of AgNPs@AV hybrids is detected by carrying out the cell viability measurement on Human Dermal Fibroblasts (HDF) cells, the results show that no obvious cytotoxicity is observed. Compared with Vera gel and Ag NPs (washed from Vera gel) alone, AgNPs@AV hybrids possess more excellent antibacterial activity on E. coli even at very low concentration.

How supramolecular chemistry interplays between the eastern philosophy and the complexity theory relationship? From which point could we start to speak about the fundamental self-organization process that seems to be “the driving force that lead up to the evolution of the biological word from the inanimate matter”? We think the best way is to focus on the core, and move around a core concept: the self-processes in Nature are the starting point for the whole organic world. Taking suggestion from the old eastern philosophy and observing the recent western theory in this paper we will evidence some analogies between the two apparent different thoughts and show that both approaches want to know more about the emerging of life from inanimate matter. In this perspective we underline that Supramolecular Chemistry, investigating the emerging behaviour or properties of the whole complex system, has a central role to understand the spontaneous evolution of Nature. If the self-organization is a conveyor belt of non-animated to animated complex matter, what are the gears of this engine of Nature able to generate Life and new living beings? We cannot provide a definitive answer to this question, however we can recall some acutely relevant research. In this paper we introduce, first, some basic principles of the ancient eastern philosophy in synergy with the modern science of the complexity. Second, the theories dealing with autopoietic systems and dissipative structures, will be presented in order to compare biological and social mechanisms with the (organic) chemistry world. Finally, we report on a few aspects of supramolecular chemistry of guanosine derivatives and their implications in material sciences, medicine and nanotechnology.

We report on the synthesis and self-assembly of a guanosine derivative bearing an alkyloxy side group under different environmental conditions. This derivative was found to spontaneously form ordered supramolecular nanoribbons in which the individual nucleobases are interacting through H-bonds. In toluene and chloroform solutions the formation of gel-like liquid-crystalline phases was observed. Sub-molecularly resolved scanning tunneling microscopic imaging of monolayers physisorbed at the graphite-solution interface revealed highly ordered two-dimensional networks. The recorded intramolecular contrast can be ascribed to the electronic properties of the different moieties composing the molecule, as proven by quantum-chemical calculations. This self-assembly behavior is in excellent agreement with that of 5'-O-acylated guanosines, which are also characterized by a self-assembled motif of guanosines that resembles parallel ribbons. Therefore, for guanosine derivatives (without sterically demanding groups on the guanine base) the formation of supramolecular nanoribbons in solution, in the solid state, and on flat surfaces is universal. This result is truly important in view of the electronic properties of these supramolecular anisotropic architectures and thus for potential applications in the fields of nano- and opto-electronics.

A few chiral azo compounds, which undergo reversible photochemical switching, are presented. Of these, the most interesting contain the binaphthyl moiety and belong to the C2 (derivatives 1 and 2) or C1 symmetry group (derivatives 3 and 4). These binaphthyl compounds display intense CD and high beta values. Photochemical switching has profound effects on both the CD and beta values of these compounds; in the case of compound 3, the sign of beta changes upon isomerisation. Compound 2 has, to our knowledge, the highest beta of the switches reported in the literature and also seems the most interesting owing to its fast response to photochemical stimuli. Nematic phases can be transformed into cholesteric phases with reflection bands in the visible region by doping with reasonable amounts of 1 and 2. The reflection colours can be changed reversibly by photoisomerisation of the switches. Thermal reversion of the colourless UV photostationary state to the green isomeric EE state or to intermediate coloured states is temperature dependent. This can allow the thermal history of a sample to be traced.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO PROGRAMA DE EXCELENCIA ACADEMICA Corpos relativamente pequenos do sistema solar não possuem atmosfera (ou muito rarefeita, chamada exosfera) e nem campo magnético: encontram-se praticamente desprotegidos da influência do ambiente espacial no qual estão inseridos. Tais corpos (como a maioria dos asteroides, luas e cometas distantes do Sol), estão sujeitos aos efeitos do chamado intemperismo espacial. Com o objetivo de simular e estudar este fenômeno em laboratório, três amostras de meteoritos do tipo condrito ordinário foram irradiadas por feixes de H(positivo) com energia de 1,0 MeV. Uma das amostras foi, também, irradiada por feixe de N(positivo) de 2,0 MeV. Os efeitos da irradiação foram monitorados por espectroscopias Raman e UV-VIS-NIR. Os resultados Raman mostram variações sistemáticas do número de onda, da intensidade e da largura das bandas vibracionais estudadas, evidências de modificações estruturais. As seções de choque de destruição das ligações Si-O presentes nas estruturas cristalinas foram determinadas. A espectroscopia UV-VIS-NIR por refletância de esfera integrada foi usada para monitorar as modificações nas características espectrais. Os espectros obtidos mostram escurecimento e avermelhamento progressivos das amostras irradiadas; a amplitude destas modificações depende do conteúdo inicial de ferro na estrutura. É proposto que o avermelhamento observado com o aumento da fluência (ou dose) da irradiação deve-se ao aumento do coeficiente de absorção na faixa azul que, por sua vez, decorre da diminuição do gap óptico do material. Estes resultados são relevantes para a modelagem da evolução físico-química de asteroides expostos ao vento solar. Relatively small bodies in the solar system have no atmosphere (or very thin, called the exosphere) and no magnetic field: they are virtually unprotected from the influence of the space environment in which they are inserted. Such bodies (like most asteroids, moons, and comets far from the sun), are subject to the effects of so-called space weathering. To simulate and study this phenomenon in the laboratory, three samples of ordinary chondrite meteorites were irradiated by H(positive) beams with 1.0 MeV energy. One of the samples was also irradiated by a 2.0 MeV N(positive) beam. The effects of irradiation were monitored by Raman and UV-VIS-NIR spectroscopies. The Raman results show systematic variations in the wavenumber, intensity, and width of the studied vibrational bands, evidence of structural modifications. The shock sections of the destruction of Si-O bonds present in the crystalline structures were determined. Integrated sphere reflectance UV-VIS-NIR spectroscopy was used to monitor changes in spectral characteristics. The obtained spectra show progressive darkening and reddening of the irradiated samples; The extent of these modifications depends on the initial iron content in the structure. It is proposed that the redness observed with the increase of irradiation creep (or dose) is due to the increase in the absorption coefficient in the blue band, which, in turn, results from the decrease of the optical gap of the material. These results are relevant for modeling the physicochemical evolution of asteroids exposed to the solar Wind.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTITUIÇÕES COMUNITÁRIAS DE ENSINO PARTICULARES Diante da importância terapêutica dos 1,2,3-triazóis e da versatilidade da reação de cicloadição 1,3-dipolar de Huisgen catalisada por cobre (reação CuAAC), o presente trabalho propõe a síntese de novos 1,2,3-triazóis-1,4-dissubstituídos abordando-se o conceito de hibridização molecular que associa ao núcleo triazólico outros grupos farmacofóricos privilegiados. Os compostos sintetizados foram divididos em duas séries e avaliados quanto ao potencial anticâncer, antileishmanial e distúrbios do sistema do nervoso central. Para obtenção da primeira série de triazóis utilizou-se como precursores aril azidas preparadas a partir de anilinas e éter propargílicos obtidos a partir de fenóis. A etapa chave da reação de CuAAC levou a obtenção dos 1,2,3-triazóis-1,4-dissubstituídos com rendimentos entre 50 e 85 porcento. Os compostos obtidos foram avaliados em diferentes linhagens celulares de glioblastoma (GBM, U87), incluindo linhagens celulares humanas altamente resistentes como a GBM02, GBM95, onde os compostos 2,2- (4,4-((1,3-phenilenebis(oxi))bis(methileno))bis(1H-1,2,3-triazol-4,1diyl))dibenzaldeído e (E)-4-metil-N-(2-(4-(fenoximetil)-1H-1,2,3triazolil)benzilideno)benzenosulfonohidrazida foram os mais ativos, com IC50 de 28,7 e 30,3 uM, respectivamente. Também foram avaliados nas linhagens de câncer de pulmão e próstata (A549, 22Rv1), entretanto, os compostos analisados não apresentaram atividade frente a estas linhagens celulares. Para a síntese da segunda série de compostos híbridos, tais quais os a-hidroxi-1,2,3-triazóis e benzocromenostriazóis, utilizou-se como materiais de partida aril azidas, preparadas através de ácidos aril borônicos e álcoois propargílicos, preparados a partir de benzaldeídos comerciais. A reação CuAAC na presença de metóxido de sódio levou a obtenção dos novos a-hidroxi-1,2,3-triazóis com rendimentos entre 35 e 75 porcento. A partir dos a-hidroxi-1,2,3-triazóis obtidos, realizou-se a reação de ativação C-H catalisada por paládio para obtenção benzocromenos-triazóis com rendimentos entre 35 e 40 porcento. Esses compostos foram avaliados como inibidores do transportador de glicina (Gly T1), transportadores relacionados a distúrbios neurológicos, e o composto (2-bromofenil)(1-(4-bromofenil)-1H-1,2,3-triazol-4-il)metanol apresentou 42porcento de inibição e IC50 de 13 uM, sendo este o melhor resultado de toda a série. Os compostos obtidos foram avaliados quanto a atividade antileishmanial (L. amazonenses), sendo que os compostos 2,2-(4,4-((1,3- phenilenebis(oxi))bis(methileno))bis(1H-1,2,3-triazol-4,1diyl)) dibenzaldeído e (E)-4-metil-N-(2-(4-(fenoximetil)-1H-1,2,3triazolil)benzilideno) benzenosulfonohidrazida apresentaram os melhores resultados, com IC50 de 8,85 e 8,81 uM, respectivamente. Todos os compostos sintetizados foram caracterizados por técnicas de espectroscopia de ressonância magnética nuclear (RMN), infravermelho (IV) e espectrometria de massas (CG-MS). In view of the therapeutic importance of 1,2,3-triazoles and the versatility of the copper-catalyzed Huisgen 1,3-dipolar cycloaddition (CuAAC), the present work proposes the synthesis of new compounds containing 1,2,3-triazoles-1,4-disubstituted derivatives by addressing the concept of molecular hybridization to obtain various triazole-containing compounds associated with other privileged pharmacophoric groups. The compounds synthesized were divided into two series and evaluated for their anticancer potential, as antileishmanial and central nervous system disorders. In order to the first series of triazoles, aryl azides were prepared from commercial anilines and propargylic ethers were obtained from commercial phenols. The key step of the CuAAC reaction afforded of 1,2,3-triazoles-1,4-disubstituted 50 - 85 percent in yields. All compounds were evaluated in different glioblastoma cell lines (GBM), including highly resistant human cell lines such as GBM02, GBM95, in which compounds 2,2-(4,4-((1,3 henylenebis(oxy))bis(methylene))bis(1H-1,2,3-triazole-4,1-diyl))dibenzaldehyde and (E)-4-methyl-N-(2-(4-(phenoxymethyl)-1H-1,2,3-triazol-1-yl)benzylidene)benzenesulfonohydrazide were the most active, with IC50 of 28.7 and 30.3 uM, respectively. The triazole derivatives were also evaluated for the lung and prostate cancer strains (A549, 22Rv1), however, the compounds analyzed did not show activity in these cell lines. For the synthesis of the second series of hybrid compounds such as a-hydroxy-1,2,3-triazoles and benzochromenes-triazoles, aryl azides were prepared from aryl boronic acids and the propargylic alcohols from commercial benzaldehydes. The CuAAC reaction in the presence of sodium methoxide provided the novel a-hydroxy-1,2,3-triazoles in 35 and 75 percents yields. The a-hydroxy-1,2,3-triazoles, were aplied palladium-catalyzed intermolecular (C-O) cyclization reaction and provided benzocromenes-triazoles in 35-40 percent yields. These compounds were evaluated as inhibitors of glycine transporter (Gly T1), which are related to neurological disorders. Therefore, compound (2-bromophenyl) (1-(4-bromophenyl)-1H-1,2,3-triazol-4-yl)methanol showed the best result with 42 percent of inhibition and IC50 of 13 uM. All compounds were avaluated for antileishmanial activity (L. amazonenses), compounds 2,2-(4,4-((1,3-phenylenebis(oxy))bis(methylene))bis(1H-1,2,3-triazole-4,1-diyl))dibenzaldehyde and (E)-4-methyl-N-(2-(4-(phenoxymethyl)-1H-1,2,3-triazol-1-yl)benzylidene)benzenesulfonohydrazide presented the best results, with IC50 de 8,85 e 8,81 uM, respectively. All the compounds synthesized were characterized by nuclear magnetic resonance (NMR), infrared (FTIR) spectroscopy and mass spectrometry (GC-MS) techniques.

PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO COORDENAÇÃO DE APERFEIÇOAMENTO DO PESSOAL DE ENSINO SUPERIOR CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO PROGRAMA DE SUPORTE À PÓS-GRADUAÇÃO DE INSTS. DE ENSINO O uso de fibras naturais como reforço em materiais compósitos vem ganhando destaque em diversos setores industriais, principalmente devido às restrições ambientais, que impõem requisitos legais relacionados ao uso de produtos sintéticos, visando a reutilização e substituição de matérias-primas não renováveis. As fibras naturais são biodegradáveis e apresentam propriedades e morfologia muito atraentes. Dentre elas, novas categorias de fibras estão sendo investigadas, como é o caso da fibra de piaçava, oriunda da palmeira Attalea funifera Martius. Sua fibra longa, lisa, resistente e de textura impermeável apresenta propriedades mecânicas semelhantes às fibras de coco, amplamente utilizadas pela indústria. Um dos desafios no uso dessas fibras como reforço em materiais compósitos é melhorar a interação entre a fibra e matriz polimérica, uma vez que as fibras naturais são hidrofílicas e as matrizes são hidrofóbicas, desenvolvendo interfaces fracas. Em alguns casos, tratamentos químicos específicos (por exemplo, o método de mercerização) podem melhorar esta interface, removendo parte da lignina e celulose de fibras, tornando a superfície rugosa compatível com a matriz polimérica. Neste trabalho, vários parâmetros foram avaliados através de MEV, microCT, FTIR e microscopia de varredura laser confocal (CLSM) da fibra de piassava antes e depois da mercerização em solução aquosa de NaOH a 10 por cento em peso. As análises permitiram avaliar que o tratamento alcalino promoveu uma limpeza profunda na superfície das fibras, removendo protrusões de sílicas do vegetal, com aumento do índice de cristalinidade, além de remover frações de lignina, hemicelulose, celulose, ceras e outras impurezas, causando desfibrilação do tecido. Também houve aumento da área superficial, rugosidade e porosidade das fibras após o tratamento químico. The use of natural fibers to reinforce composite materials has been gaining considerable notice in many industrial fields. This is mainly due to environmental restrictions, which impose legal requirements related to the use of synthetic products, aiming at the reuse and replacement of non-renewable raw materials, which cause less damage to the environment. Natural fibers are biodegradable, renewable resources with very attractive properties and morphology. Among them, new categories of fibers are being investigated, as the case of piassava fiber, from the palm of Attalea funifera Martius. Its long, smooth, sturdy and waterproof textured fiber has similar mechanical properties to the coconut fibers widely used in the industry. One of the challenges in using these fibers as reinforcement in composite materials is to improve the interaction between fiber and polymer matrix, since the natural fibers are hydrophilic and the matrices are hydrophobic, developing weak interfaces. In some cases, specific chemical treatments (eg the mercerization method) can improve this interface by removing part of the lignin and cellulose from fibers, making the rough surface compatible with the polymer matrix. In this work, several parameters were evaluated through MEV, microCT, FTIR and confocal laser scanning microscopy (CLSM) of piassava fibers, before and after mercerization with 10 percent by weight aqueous NaOH solution. The analyzes allowed to evaluate that the alkaline treatment promoted a deep cleaning on the surface of the fibers, removing protrusions of silica from the vegetable, besides removing lignin, hemicellulose, cellulose, waxes and other impurities, causing tissue defibrillation. Also, it was able to increase the surface area, roughness and porosity of the fibers after chemical treatment.

A intensificação de processos é importante na busca de equipamentos e reações menos nocivos e seguros, um exemplo é a aplicação de microrreatores. A indústria farmacêutica é a maior beneficiária dessa tecnologia, pois os microrreatores, dispositivos com microcanais de até 100 µm, podem reduzir em anos o tempo necessário para desenvolver e produzir um novo fármaco e podem ser montados em unidades industriais extremamente pequenas e compactas. O aumento de casos de diabetes no Brasil na última década vem incentivando a busca por novos fármacos. Neste trabalho, a aplicação de microrreatores capilares é estudada na síntese do (Z)-5-(4-hidroxi-3-metoxibenzilideno)2,4-tiazolidinadiona (HMTZD) e do (Z)-5-(3-hidroxi-4-metoxibenzilideno)2,4-tiazolidinadiona (MHTZD), obtidos da reação de 2,4-tiazolidinediona (TZD) com 4-hidroxi-3-metoxibenzaldeído (Vanilina) e com seu isômero, 3-hidroxi-4-metoxibenzaldeído (Isovanilina), que podem ser utilizados na síntese de moléculas com atividade biológica. Foram obtidos rendimentos máximos do produto HMTZD, 98% em 480 min de reação e do produto MHTZD, 73% em 120 min de reação, contrariando a literatura que apresenta um tempo de reação para essa síntese de 20 h a 40 h. Na síntese em fluxo no microrreator, ficou evidente que quanto maior a temperatura maior a conversão de TZD e o rendimento do produto, chegando a valores de 100%, para a temperatura de 160°C em etanol. A produção no processo batelada e no microrreator foram calculadas e, quando comparadas, mostraram que apenas dois microrreatores de 1 mL em sua melhor condição de operação são capazes de produzir três vezes mais que um reator batelada de 60 mL. Pelo estudo de cinética, a reação utilizando etanol não favorece a formação de reações em paralelo ou em série. As análises qualitativas comprovaram que os produtos esperados foram formados e com alto grau de pureza. The process intensification is important in the search for less harmful and safe equipment and reactions, an example is the application of microreactors. The pharmaceutical industry is the largest beneficiary of this technology because microreactors, devices with microchannels up to 100 µm, can reduce the time required to develop and produce a new drug in years and can be mounted in extremely small and compact industrial units. The increase in diabetes cases in Brazil in the last decade has been encouraging the search for new drugs. In this work, the application of capillary microreactors is studied in the synthesis of (Z)-5-(4-hydroxy-3-methoxybenzylidene)2,4-thiazolidinedione (HMTZD) and (Z)-5-(3-hydroxy-4- methoxybenzylidene)2,4-thiazolidinedione (MHTZD), obtained from the reaction of 2,4-thiazolidinedione (TZD) with 4-hydroxy-3-methoxybenzaldehyde (Vanillin) and its isomer, 3-hydroxy-4-methoxybenzaldehyde (Isovanillin), which can be used in the synthesis of molecules with biological activity. Maximum yields of 98% in 480 min, for the product HMTZD, and 73% in 120 min, for the product MHTZD, were obtained, contradicting literature that shows a reaction time for this synthesis of 20 h to 40 h. In the flow synthesis in the microreactor, it was evident that the higher the temperature the higher the conversion of TZD and the yield of the product, reaching 100%, in ethanol working with the temperature of 160°C. The production in the batch process and the microreactor were calculated and, when compared, showed that only two 1 mL microreactors in their best operating condition are able to produce three times more than a 60 mL batch reactor. By the study of kinetics, the reaction using ethanol does not favor the formation of reactions in parallel or in series. The qualitative analyzes showed that the expected products was formed and with a high degree of purity.