Articoli di riviste: "Colloïde nanocomposite"

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Park, Jong-Min, Chan-Woo Lee, Wan-Sul Lee, Kyung-Mo Yang, Jun-Ho Lee, Gi-Yong Nam, Seong-Hoon Lee, Yong Sang Lee, Youngkwan Lee e Jae-Do Nam. "MONTMORILLONITE-REINFORCED NATURAL RUBBER NANOCOMPOSITES THROUGH EMULSION STABILIZATION–DESTABILIZATION METHOD". Rubber Chemistry and Technology 85, n. 2 (1 giugno 2012): 165–79. http://dx.doi.org/10.5254/rct.12.88978.

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Abstract A nanoplatelet of montmorillonite (MMT) was incorporated in the natural rubber (NR) matrix at a high loading content using a newly developed stabilization–destabilization process in the colloid states. Examination of the surface charge of the colloid drops by zeta potential measurement led to the identification of the stable and unstable conditions of the colloid mixture as well as each colloid system as a function of pH. The stabilized mixture of the MMT and NR colloids was subsequently destabilized by changing the pH of the mixture to achieve a well-dispersed and intercalated NR/MMT precipitate. The resulting NR/MMT nanocomposites provided an exfoliated MMT morphology up to 25 phr, and the mechanical properties and aging tolerance of the resulting nanocomposite vulcanizates were substantially enhanced by the incorporated MMT nanofillers. The developed stabilization–destabilization methodology ensured a highly loaded MMT rubber composite system, which could be used to obtain high performance NR/MMT nanocomposite systems with ease without using high-shear processing techniques.

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Krkljes, Aleksandra, Miodrag Mitric e Zorica Kacarevic-Popovic. "Radiolytic synthesis and characterization of PVA/Au nanocomposites: The influence of pH values". Chemical Industry 62, n. 3 (2008): 101–6. http://dx.doi.org/10.2298/hemind0803101k.

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Nanocomposites which consist of polymer matrix and nanoparticles of noble metal are a very important class of nanomaterials. The optical properties of these materials are strongly dependent on the nanoparticles size as well as on the synthesized procedure of nanocomposites preparation. In this work the Au nanoparticles were synthesized by the simple radiolytic procedure, using steady state gamma irradiation, under different pH values. PVA/Au nanocomposite films were obtained by solvent evaporation from Au colloids. UV-Vis absorption spectra of Au colloids show absorption in the range of 450 to 650 nm with the maximum around 520 nm, which is the typical plasmon band of Au nanoparticles. Absorption spectra of PVA/Au nanocomposites are red shifted compared to corresponding primary Au colloids. This red shift is not result of any change in particle size distribution and can be explained by the change of dielectric property of surrounding medium. IR spectra indicated anchoring the OH groups of PVA molecule at the cluster surface. This effect limits the growing of the metal clusters and confirmed that the PVA is a god matrix for in situ synthesis of Au nanoparticles. The size of Au nanoparticles is dependent on the experimental conditions. Obtained results indicated that the pH value of solution played an important role. The values of absorption maximum (?max) were not dependent on the concentration of Au cations, but show strong dependence on the pH value of the initial solution. The increase of pH value reduced the mean diameters of nanoparticles. The lowest value of ?max was obtained for colloid with pH 7, which theoretically corresponds to the nanoparticles with minimum dimension. These results are in agreement with the XRD measurement of PVA/Au nanocomposite films and theoretical calculations. According to obtained results of radiolytic synthesis of Au nanoparticles in PVA solution can be conclude that it is possible to control the particle size by tuning the pH value of solution.

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Li, Bao Guang, Yong Zi Xu, Lu Bai, Huan Dai, Cai Cai Xie e Hai Bin Li. "Ultrasonic Effect on Fabrication of Intercalated MgAl-LDH/PVA Nanocomposites via Exfoliation-Adsorption Route". Key Engineering Materials 727 (gennaio 2017): 532–36. http://dx.doi.org/10.4028/www.scientific.net/kem.727.532.

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Glycine intercalated Mg/Al-layered double hydroxides (LDH-G)/PVA nanocomposites were prepared via exfoliation-adsorption route based on exfoliation of LDH-G in formamide. The effect of ultrasonic treatment on the fabrication of LDH-G/PVA nanocomposites was investigated. The results of XRD suggest that chains of PVA with double layer arrange into the galleries of restacking LDH platelets with the formation of intercalated-type nanocomposite. Experiments present that ultrasonic treatment on the colloid of LDH-G/PVA increases the amount of platelet which forms the intercalated phase, and improves the regularity of LDH-G arrays in the c direction. It is demonstrated the exfoliated LDH platelets orient in its normal paralleling the flow direction at the high shear rate induced by ultrasound. Simultaneously, under the enhanced temperature caused by long term of ultrasonic treatment, PVA chains extend more and the interaction between PVA chains and LDH layers is reinforced. A model was proposed for various stages of LDH platelets and PVA chains in their mixed colloid during ultrasonic treatment which describes the fabrication of improved hybrid structure.

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Susilowati, Endang, Mohammad Masykuri, Maria Ulfa e Dyah Puspitasari. "Preparation of Silver-Chitosan Nanocomposites Colloidal and Film as Antibacteri Material". JKPK (Jurnal Kimia dan Pendidikan Kimia) 5, n. 3 (31 dicembre 2020): 300. http://dx.doi.org/10.20961/jkpk.v5i3.46711.

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Colloidal nanocomposites silver-chitosan have been made. Silver nanoparticles were produced by chemical reduction methods assisted microwave irradiation using chitosan from crab shells as a reducing agent and stabilizer, AgNO3 as a precursor and NaOH as an accelerator. This study investigated AgNO3 concentration toward localized surface plasmon resonance (LSPR) phenomenon of nanocomposites colloidal. The size and shape of the silver nanoparticles were confirmed by TEM. Furthermore, the stability of the storage was observed for twelve weeks. Colloidal and film nanocomposites silver- chitosan have been made by casting method by drying at room temperature. After that, the film characterization was carried out, including swelling with gravimetry methods and surface morphology using scanning electron microscopy (SEM). Diffusion methods tested colloid antibacterial activity and silver-chitosan nanocomposite film’s against E. Coli and S. Aureus. The results showed that the formation of silver nanoparticles was identified by the LSPR absorption band's appearance at 413-419 nm. The increasing of AgNO3 concentration increased the intensity of the LSPR absorption band. Silver nanoparticles with sizes of about 3-9 nm are spherical. The silver nanoparticles were stable at 12 weeks of storage. The higher AgNO3 concentration tends to increase the swelling of the film. The surface of the silver-chitosan nanocomposite film’s was rougher than that of the chitosan film. The higher the silver nanoparticle concentration, the higher the colloid and film antibacterial activity against E. Coli and S. Aureus.

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Lozovski, V. Z., A. G. Vasiljev, T. A. Vasyliev, I. S. Petrik, A. M. Eremenko e N. P. Rybalchenko. "Resonance properties of the solution of quercetin stabilized silver nanoparticles in a nutrient medium". Himia, Fizika ta Tehnologia Poverhni 15, n. 1 (30 marzo 2024): 86–93. http://dx.doi.org/10.15407/hftp15.01.086.

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Changes in the light absorption spectrum when mixing colloids of Ag nanoparticles with a diameter of 7 nm in a quercetin shell with a nutrient medium were studied in the present article. Colloids of silver nanoparticles were prepared by chemical reduction of AgNO3 silver salt with sodium tetrahydroborate (NaBH4) in an aqueous solution. Quercetin is a flavonoid of plant origin. It was chosen to stabilize nanoparticles due to its capability to form complexes with metals. The quercetin shell is capable to preserve the bactericidal effect of silver NPs on bacteria and weaken their toxic effect on healthy cells of the human body. The absorption spectra of solutions from which nanoparticle colloids were synthesized were used to control the synthesis result. The Luria-Bertani nutrient medium was studied in the work. Absorption spectra of the nutrient medium and nanoparticle colloids were again obtained immediately before mixing. Then, the nutrient medium and the nanoparticle colloid were mixed in volume proportion 1:1, and the absorption spectrum of the mixture was mesured. The absorption spectrum of the mixture did not reproduce a simple overlay of the nanoparticle colloid spectrum on the absorption spectrum of the nutrient medium. To describe the experimental spectra, a colloid of stabilized silver nanoparticles, a nutrient medium, and a mixture of a colloid and a nutrient medium were considered by nanocomposites of various organic and inorganic nanoparticles in a liquid. As a result, experimental absorption spectra were theoretically approximated by related to these nanoparticles elementary oscillators. The error of the discrepancy between experimental and simulated spectra did not exceed 3%. Analysis of the complex spectra of the mixture of the nanoparticle colloid and the nutrient medium has shown that the frequency of the localized plasmon resonance in the nanoparticles most likely does not change. It means that for studying the effect of nanoparticles on biological objects (microbes or viruses), the wavelength of external irradiation must be chosen equal to the wavelength of LPR in the colloid.

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Velgosova, Oksana, Lívia Mačák, Erika Múdra, Marek Vojtko e Maksym Lisnichuk. "Preparation, Structure, and Properties of PVA–AgNPs Nanocomposites". Polymers 15, n. 2 (10 gennaio 2023): 379. http://dx.doi.org/10.3390/polym15020379.

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The aim of the work was to prepare a polymer matrix composite doped by silver nanoparticles and analyze the influence of silver nanoparticles (AgNPs) on polymers’ optical and toxic properties. Two different colloids of AgNPs were prepared by chemical reduction. The first colloid, a blue one, contains stable triangular nanoparticles (the mean size of the nanoparticles was ~75 nm). UV–vis spectrophotometry showed that the second colloid, a yellow colloid, was very unstable. Originally formed spherical particles (~11 nm in diameter) after 25 days changed into a mix of differently shaped nanoparticles (irregular, triangular, rod-like, spherical, decahedrons, etc.), and the dichroic effect was observed. Pre-prepared AgNPs were added into the PVA (poly(vinyl alcohol)) polymer matrix and PVA–AgNPs composites (poly(vinyl alcohol) doped by Ag nanoparticles) were prepared. PVA–AgNPs thin layers (by a spin-coating technique) and fibers (by electrospinning and dip-coating techniques) were prepared. TEM and SEM techniques were used to analyze the prepared composites. It was found that the addition of AgNPs caused a change in the optical and antibiofilm properties of the non-toxic and colorless polymer. The PVA–AgNPs composites not only showed a change in color but a dichroic effect was also observed on the thin layer, and a good antibiofilm effect was also observed.

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ALAM, FAHAD, SAJID ALI ANSARI, WASI KHAN, M. EHTISHAM KHAN e A. H. NAQVI. "SYNTHESIS, STRUCTURAL, OPTICAL AND ELECTRICAL PROPERTIES OF IN-SITU SYNTHESIZED POLYANILINE/SILVER NANOCOMPOSITES". Functional Materials Letters 05, n. 03 (settembre 2012): 1250026. http://dx.doi.org/10.1142/s1793604712500269.

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Polyaniline (PANI) is recognized as one of the most important conducting polymers due to its high conductivity and good stability. In this paper, polyaniline/silver (PANI/Ag) nanocomposites were synthesized by in-situ polymerization of aniline using ammonium peroxydisulphate (APS) as oxidizing agent with varying concentration of Ag nanoparticles colloids (0 ml, 25 ml and 50 ml). Silver nanoparticles were synthesized separately in colloidal form from silver nitrate (Ag2NO3) with the help of reducing agent sodium borohydride (NaBH4). The PANI/ Ag nanocomposites were characterized by XRD, SEM, AFM, UV-visible, temperature dependent resistivity and dielectric measurements. All samples show a single phase nature of the nanoparticles. The electrical resistivity as function of temperature was measured in the temperature range 298–383 K, which indicates a semiconducting to metallic transition at 373 K and 368 K for 25 ml and 50 ml silver colloid samples, respectively.

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LEPESHKIN, N. N., W. KIM, V. P. SAFONOV, J. G. ZHU, R. L. ARMSTRONG, C. W. WHITE, R. A. ZUHR e V. M. SHALAEV. "OPTICAL NONLINEARITIES OF METAL-DIELECTRIC COMPOSITES". Journal of Nonlinear Optical Physics & Materials 08, n. 02 (giugno 1999): 191–210. http://dx.doi.org/10.1142/s021886359900014x.

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Nonlinear optical properties of metal-dielectric composites, such as fractal colloid aggregates and clusters created by ion implantation, are studied. Strong fluctuations of local fields result in huge enhancements of optical nonlinearities in fractal colloid aggregates. The real and imaginary parts of the cubic susceptibility of silver colloid aggregates are measured. It is found that the coefficient of nonlinear absorption strongly depends on the laser wavelength and intensity. Optical limiting effect in fractal silver colloids is observed. Nondegenerate forward four-wave mixing technique is used to investigate the third-order nonlinear susceptibility for nanocomposite material with Au nanocrystals formed inside a SiO 2 glass matrix. The Au nanocrystals are formed by the ion implantation and annealing method that produces very high volume fraction of nanoparticles. The large value |χ(3)|=1.3×10-7 esu is measured. Two characteristic relaxation times, 5.3 ps and 0.66 ps, are estimated from the detuning curve of |χ(3)|, as the probe beam wavelength changes. A novel class of optical materials, microcavities doped with nanostructured fractal aggregates, is also studied. In our experiments, lasing at extremely low pump intensities, below 1 mW, and dramatically enhanced Raman scattering was observed in microcavity/fractal composites.

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Irimpan, Litty, V. P. N. Nampoori e P. Radhakrishnan. "Enhanced luminescence and nonlinear optical properties of nanocomposites of ZnO–Cu". Journal of Materials Research 23, n. 11 (novembre 2008): 2836–45. http://dx.doi.org/10.1557/jmr.2008.0364.

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In this article, we present the spectral and nonlinear optical properties of ZnO–Cu nanocomposites prepared by colloidal chemical synthesis. The emission consisted of two peaks. The 385-nm ultraviolet (UV) peak is attributed to ZnO and the 550-nm visible peak is attributed to Cu nanocolloids. Obvious enhancement of UV and visible emission of the samples is observed and the strongest UV emission of a typical ZnO–Cu nanocomposite is over three times stronger than that of pure ZnO. Cu acts as a sensitizer and the enhancement of UV emission are caused by excitons formed at the interface between Cu and ZnO. As the volume fraction of Cu increases beyond a particular value, the intensity of the UV peak decreases while the intensity of the visible peak increases, and the strongest visible emission of a typical ZnO–Cu nanocomposite is over ten times stronger than that of pure Cu. The emission mechanism is discussed. Nonlinear optical response of these samples is studied using nanosecond laser pulses from a tunable laser in the wavelength range of 450–650 nm, which includes the surface plasmon absorption (SPA) band. The nonlinear response is wavelength dependent and switching from reverse saturable absorption (RSA) to saturable absorption (SA) has been observed for Cu nanocolloids as the excitation wavelength changes from the low absorption window region to higher absorption regime near the SPA band. However, ZnO colloids and ZnO–Cu nanocomposites exhibit induced absorption at this wavelength. Such a changeover in the sign of the nonlinearity of ZnO–Cu nanocomposites, with respect to Cu nanocolloids, is related to the interplay of plasmon band bleach and optical limiting mechanisms. The SA again changes back to RSA when we move over to the infrared region. The ZnO–Cu nanocomposites show self-defocusing nonlinearity and good nonlinear absorption behavior. The nonlinear refractive index and the nonlinear absorption increases with increasing Cu volume fraction at 532 nm. The observed nonlinear absorption is explained through two-photon absorption followed by weak free-carrier absorption and interband absorption mechanisms. This study is important in identifying the spectral range and composition over which the nonlinear material acts as a RSA-based optical limiter. ZnO–Cu is a potential nanocomposite material for the light emission and for the development of nonlinear optical devices with a relatively small limiting threshold.

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Boissière, Michel, Joachim Allouche, Roberta Brayner, Corinne Chanéac, Jacques Livage e Thibaud Coradin. "Design of Iron Oxide/Silica/Alginate HYbrid MAgnetic Carriers (HYMAC)". Journal of Nanoscience and Nanotechnology 7, n. 12 (1 dicembre 2007): 4649–54. http://dx.doi.org/10.1166/jnn.2007.18118.

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A large number of natural and synthetic polymers have already been evaluated for the design of nanomaterials incorporating magnetic nanoparticles for biomedical applications. The possibility to use hybrid (bio)-organic/inorganic nano-carriers have been much less studied. Here we describe the design of Hybrid MAgnetic Carriers (HYMAC) consisting of alginate/silica nanocomposites incorporating magnetite nanoparticles, based on a spray-drying approach. Transmission electron microscopy and X-ray energy dispersive spectrometry confirm the successful incorporation of magnetic colloids within homogeneous hybrid capsules. X-ray diffraction data suggest that surface iron ions are partially desorbed by the spray-drying process, leading to the formation of lepidocrocite and of an iron silicate phase. Magnetic measurements show that the resulting nanocomposites exhibit a superparamagnetic behaviour with a blocking temperature close to 225 K. Comparison with un-silicified capsules indicate that the mineral phase enhances the thermal stability of the polymer network and do not modify of the amount of incorporated iron oxide nanoparticles. Moreover, evaluation of nanocomposite up-take by fibroblasts indicates their possible internalization. A selective intracellular alginate degradation is observed, suggesting that these HYMAC nanomaterials may exhibit interesting properties for the design of drug delivery devices.

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Vodnik, Vesna V., Dušan K. Božanić, Nataša Bibić, Zoran V. Šaponjić e Jovan M. Nedeljković. "Optical Properties of Shaped Silver Nanoparticles". Journal of Nanoscience and Nanotechnology 8, n. 7 (1 luglio 2008): 3511–15. http://dx.doi.org/10.1166/jnn.2008.144.

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The influence of shape and dielectric property of surrounding media on surface plasmon absorption band of silver nanoparticles was studied. Spherical silver nanoparticles (d = 5.6 nm) synthesized in water using NaBH4 as a reducing agent are transferred in non-polar solvent (chloroform) with phase-transfer reagent oleylamine. The absorption spectrum of oleylamine-capped silver nanoparticles dispersed in chloroform shows a strong surface plasmon resonance band that is 19 nm red-shifted compared to unmodified particles in water. The values for peak position and corresponding half widths are compared with theoretical calculations based on Mie theory. Prismatic and plate-like silver nanoparticles were synthesized in water using trisodium citrate as a reducing agent and cetyltrimethylammonium bromide as stabilizer. Due to structural anisotropy of prismatic and plate-like silver nanoparticles three surface plasmon resonance bands were observed in absorption spectrum. Nanocomposites consisting of non-spherical silver nanoparticles and polyvinyl alcohol exhibit different optical properties compared to water colloid. Instead of three surface plasmon bands, nanocomposite film has only one peak at 460 nm. Reason for appearance of single surface plasmon resonance band in nanocomposite film was discussed according to Maxwell-Garnet theory.

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Nocerino, Valeria, Bruno Miranda, Chiara Tramontano, Giovanna Chianese, Principia Dardano, Ilaria Rea e Luca De Stefano. "Plasmonic Nanosensors: Design, Fabrication, and Applications in Biomedicine". Chemosensors 10, n. 5 (20 aprile 2022): 150. http://dx.doi.org/10.3390/chemosensors10050150.

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Current advances in the fabrication of smart nanomaterials and nanostructured surfaces find wide usage in the biomedical field. In this context, nanosensors based on localized surface plasmon resonance exhibit unprecedented optical features that can be exploited to reduce the costs, analytic times, and need for expensive lab equipment. Moreover, they are promising for the design of nanoplatforms with multiple functionalities (e.g., multiplexed detection) with large integration within microelectronics and microfluidics. In this review, we summarize the most recent design strategies, fabrication approaches, and bio-applications of plasmonic nanoparticles (NPs) arranged in colloids, nanoarrays, and nanocomposites. After a brief introduction on the physical principles behind plasmonic nanostructures both as inherent optical detection and as nanoantennas for external signal amplification, we classify the proposed examples in colloid-based devices when plasmonic NPs operate in solution, nanoarrays when they are assembled or fabricated on rigid substrates, and nanocomposites when they are assembled within flexible/polymeric substrates. We highlight the main biomedical applications of the proposed devices and offer a general overview of the main strengths and limitations of the currently available plasmonic nanodevices.

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Stankova, Nadya, Anna Dikovska, Mihaela Koleva, Nikolay Nedyalkov, Anastas Nikolov, Dimitar Dimov e Daniela Karashanova. "LASER-ASSISTED SYNTHESIS OF WATER COLLOIDAL METALLIC NANOCOMPOSITES". Journal of Chemical Technology and Metallurgy 59, n. 4 (5 luglio 2024): 841–48. http://dx.doi.org/10.59957/jctm.v59.i4.2024.12.

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Picosecond and Nanosecond Nd:YAG laser systems with a fundamental wavelength of 1064 nm are utilizedfor green synthesis of bimetallic nanocomposites based on metal combinations of Pt/Ti, Pd/Ti, Pt/Zn and Pd/Zn. The laser assisted method is based on pulsed laser ablation of metal targets, which are immersed consecutively in bidistilled water to obtain water colloids of the corresponding bimetallic nanostructures. Comparative study of the structural and optical properties of the nanocomposites is conducted by means of transmission electron microscopy in its corresponding main modes and by optical spectrometer measurements, respectively. Suspensions of water colloids of the nanocomposites and methylene blue dye prepared in 1 : 2.5 ratio, respectively, are exposed under sunlight irradiation for 3 h. Photocatalytic activity of the nanocomposites against methylene blue (MB) dye is tested by measuring the optical absorbance of the suspensions before and after the sunlight irradiation.

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Wu, Yuchao, Yang Lan, Ji Liu e Oren A. Scherman. "Catalytic polymeric nanocomposites via cucurbit[n]uril host–guest interactions". Nanoscale 7, n. 32 (2015): 13416–19. http://dx.doi.org/10.1039/c5nr03647j.

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Polymeric nanocomposites were prepared by using cucurbit[7]uril as a ‘supramolecular anchor’, as well as stabilising ligand to immobilise catalytic transition-metal nanoparticles on the surface of methyl viologen-bearing polymeric colloids. The small metallic nanoparticles impart the nanocomposites with great potential in catalysis.

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Chaurasia, Alok, Nanda Gopal Sahoo, James T. McLeskey e Xiao Hu. "Development and Characterization of Biocompatible Fullerene [C60]/Amphiphilic Block Copolymer Nanocomposite". Journal of Spectroscopy 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/578160.

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We report a supramolecular process for the synthesis of well-defined fullerene (C60)/polymer colloid nanocomposites in an aqueous solution via complex formation. A biocompatible triblock poly(4-vinylpyridine)-b-polyethylene-b-poly(4-vinylpyridine), P4VP8-b-PEO105-b-P4VP8, was synthesized by atom transfer radical polymerization. The block copolymer formed complexes with C60in toluene and resulted in fullerene assembly in cluster form. Nanocomposite dispersion in an aqueous solution could be obtained using an aged solution of the polymer/C60/toluene solution by a solvent evaporation technique. The UV-Vis and FTIR spectroscopy confirmed the complex formation of fullerene with the polymer which plays a significant role in controlling the PDI and size of polymer/C60micelles in the toluene solution. The particle size and morphology of P4VP8-b-PEO105-b-P4VP8and P4VP8-b-PEO105-b-P4VP8/C60mixture were studied by dynamic light scattering (DLS) and transmission electron microscopy (TEM). In a cytotoxicity test, both pure polymer and the resulting polymer/C60composite in water showed more than 90% cell viability at 1 mg/mL concentration.

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Araujo, Robson T., Maria S. B. Neta, José A. H. Coaquira, Sacha B. Chaves e Fabricio Machado. "A New Design for Magnetic Poly(vinyl pivalate) for Biomedical Applications: Synthesis, Characterization, and Evaluation of Cytotoxicity in Fibroblasts, Keratinocytes, and Human Melanoma Cells". Colloids and Interfaces 6, n. 1 (21 gennaio 2022): 7. http://dx.doi.org/10.3390/colloids6010007.

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Polymers containing magnetic properties play an important role in biomedical therapies, such as embolotherapy or hyperthermia, for their differentiated properties. In this work, magnetite (Fe3O4) nanoparticles were synthesized by the coprecipitation method and dispersed into a thermoplastic matrix of poly(vinyl pivalate) through an emulsion polymerization process. The main goal was the individual encapsulation of magnetite nanoparticles to improve the magnetic response of the magneto-polymeric materials using polymerizable carboxylic acids as coating agents, minimizing the leaching of nanoparticles throughout the nanocomposite formation. For this purpose, synthesized magnetite had its surface modified by acrylic acid or methacrylic acid to improve its individual encapsulation during the polymerization step, thus generating a series of magnetic nanocomposite materials containing different amounts of magnetite intended for biomedical applications. X-ray diffractometry and TEM measurements provided a mean size of approximately 8 nm for the pure magnetite nanoparticles and a spherical morphology. Acid-functionalized Fe3O4 had a size of approximately 6 nm, while the nanocomposites showed a size of approximately 7 nm. Magnetization measurement provided a saturation magnetization value of approximately 75 emu/g and confirmed superparamagnetic behavior at room temperature. DSC analysis showed a glass transition temperature of 65 °C for poly(vinyl pivalate)-based nanocomposites. The tests realized with homopolymer and magnetic composites against different cell lineages (i.e., fibroblasts, keratinocytes, and human melanoma) to evaluate the levels of cytotoxicity showed good results in the different exposure times and concentrations used, since the obtained results showed cell viability greater than 70% compared to the control group, suggesting that the synthesized materials are very promising for medical applications.

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Wan Ikhsan, Syarifah Nazirah Wan, Norhaniza Yusof, Farhana Aziz, Ahmad Fauzi Ismail, Norazanita Shamsuddin, Juhana Jaafar, Wan Norharyati Wan Wan Salleh, Pei Sean Goh, Woei Jye Lau e Nurasyikin Misdan. "Synthesis and Optimization of Superhydrophilic-Superoleophobic Chitosan–Silica/HNT Nanocomposite Coating for Oil–Water Separation Using Response Surface Methodology". Nanomaterials 12, n. 20 (19 ottobre 2022): 3673. http://dx.doi.org/10.3390/nano12203673.

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In this current study, facile, one-pot synthesis of functionalised nanocomposite coating with simultaneous hydrophilic and oleophobic properties was successfully achieved via the sol–gel technique. The synthesis of this nanocomposite coating aims to develop a highly efficient, simultaneously oleophobic-hydrophilic coating intended for polymer membranes to spontaneously separate oil-in-water emulsions, therefore, mitigating the fouling issue posed by an unmodified polymer membrane. The simultaneous hydrophilicity-oleophobicity of the nanocoating can be applied onto an existing membrane to improve their capability to spontaneously separate oil-in-water substances in the treatment of oily wastewater using little to no energy and being environmentally friendly. The synthesis of hybrid chitosan–silica (CTS-Si)/halloysite nanotube (HNT) nanocomposite coating using the sol–gel method was presented, and the resultant coating was characterised using FTIR, XPS, XRD, NMR, BET, Zeta Potential, and TGA. The wettability of the nanocomposite coating was evaluated in terms of water and oil contact angle, in which it was coated onto a polymer substrate. The coating was optimised in terms of oil and water contact angle using Response Surface Modification (RSM) with Central Composite Design (CCD) theory. The XPS results revealed the successful grafting of organosilanes groups of HNT onto the CTS-Si denoted by a wide band between 102.6–103.7 eV at Si2p. FTIR spectrum presented significant peaks at 3621 cm−1; 1013 cm−1 was attributed to chitosan, and 787 cm−1 signified the stretching of Si-O-Si on HNT. 29Si, 27Al, and 13H NMR spectroscopy confirmed the extensive modification of the particle’s shells with chitosan–silica hybrid covalently linked to the halloysite nanotube domains. The morphological analysis via FESEM resulted in the surface morphology that indicates improved wettability of the nanocomposite. The resultant colloids have a high colloid stability of 19.3 mV and electrophoretic mobility of 0.1904 µmcm/Vs. The coating recorded high hydrophilicity with amplified oleophobic properties depicted by a low water contact angle (WCA) of 11° and high oil contact angle (OCA) of 171.3°. The optimisation results via RSM suggested that the optimised sol pH and nanoparticle loadings were pH 7.0 and 1.05 wt%, respectively, yielding 95% desirability for high oil contact angle and low water contact angle.

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Che, Hui Xin, Swee Pin Yeap, Ahmad Abdul Latif e Jit Kang Lim. "Design and Synthesis Silica-Polyelectrolyte-Iron Oxide Nanocomposite with Magnetic-Catalytic Bifunctionalities for Dye Removal". Advanced Materials Research 1024 (agosto 2014): 3–6. http://dx.doi.org/10.4028/www.scientific.net/amr.1024.3.

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Incorporation of iron oxide nanoparticles into Poly(diallydimethylammonium chloride) coated silica colloids is developed to produce novel nanocomposite. The structure is synthesized via layer-by-layer assembly with the entire process driven by electrostatic interaction. Dynamic light scattering and zeta potential measurements are employed to monitor the evolution of the nanocomposite from its constituent materials to full development of final structure. Morphology of the as-synthesized nanocomposite is observed by transmission electron microscopy. The magnetic responsiveness under low magnetic field gradient enables the aforementioned nanocomposite to be recovered for recycle purpose. The engineering application of this material is tested by taking Methylene Blue and Remazol Brilliant Blue R dyes as model system. The study reveals the efficiency and activity of the nanocomposite for dye removal during four consecutive runs.

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Petrecca, Michael J., Jerush Christopher, Orlin D. Velev e Peter S. Fedkiw. "Applications of Soft Dendritic Colloids in Li-Ion Batteries with Advanced Structure-Derived Performance". ECS Meeting Abstracts MA2022-02, n. 64 (9 ottobre 2022): 2335. http://dx.doi.org/10.1149/ma2022-02642335mtgabs.

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Adoption of electric vehicles and increasing demands of consumer electronics require electrochemical energy storage devices with high capacity and rate capabilities. Supply-chain and material-cost concerns as well as charge-rate limitations associated with irreversible lattice changes motivates the replacement of mixed-metal oxide cathodes in lithium-ion batteries (LIBs). Electrochemically active polymeric materials have emerged as promising candidates to replace metal oxides due to their high tunability and increased capacity. However, many of these materials suffer from poor intrinsic electronic conductivity and may be soluble into the electrolyte, causing irreversible capacity fade. Nanostructuring and composite formation are two polymer processing methods that can be leveraged to combat these drawbacks. The introduction of new nanostructured and nanocomposite cell components can decrease diffusion length scales, increase mechanical stability, and allow for higher electronic conductivity in polymer electrodes. Herein, we utilize a new class of polymeric materials called soft dendritic colloids (SDCs) as a platform for creating such nanocomposites. These fibrillar polymeric particles, formed via turbulent solvent-nonsovent induced phase separation, have hierarchical morphology, large aspect ratios and demonstrate pronounced adhesion and network-forming behavior. SDC-based materials have shown impressive results as nonwoven polyvinylidene difluoride separators in Li-ion batteries. Herein, we propose and present their use as Li-ion battery electrodes with advanced structural properties, derived from electroactive polymeric materials.

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20

Stojkovska, Jasmina, Jovana Zvicer, Zeljka Jovanovic, Vesna Miskovic-Stankovic e Bojana Obradovic. "Controlled production of alginate nanocomposites with incorporated silver nanoparticles aimed for biomedical applications". Journal of the Serbian Chemical Society 77, n. 12 (2012): 1709–22. http://dx.doi.org/10.2298/jsc121108148s.

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Production of nanocomposite alginate microbeads with electrochemically synthesized silver nanoparticles (AgNPs) based on electrostatic extrusion technique was investigated with respect to potentials for utilization in pharmaceutical and biomedical applications. It was shown that electrochemical synthesis of AgNPs results in reduction of practically all Ag+ ions present in the initial solution yielding stable Ag/alginate colloid solutions that were demonstrated to be suitable for sterilization, manipulation, and electrostatic extrusion with retention of AgNPs. Presence of AgNPs in alginate colloid solutions had negligible effects on the size of the produced Ag/alginate microbeads, which was chiefly determined by the applied electrostatic potential during the extrusion. On the other hand, incorporation of AgNPs within the alginate hydrogel induced slight changes in biomechanical properties determined in a biomimetic bioreactor, so that packed beds of nanocomposite Ag/alginate microbeads exhibited slightly higher dynamic compression modulus as compared to that of control alginate microbeads (154 ? 4 and 141 ? 2 kPa, respectively). On the other hand, equilibrium unconfined compression modulus was significantly lower for nanocomposite microbeads as compared to that of controls (34 ? 2 and 47 ? 0.5 kPa, respectively).

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21

Vislohuzova, T. V., N. A. Galatenko, R. A. Rozhnova, V. M. Bogatyrov e M. V. Galaburda. "Composite materials based on polyurethane with fragments of poly(vinyl butyral-vinyl acetate-vinyl alcohol) copolymer in their structure filled with silver- and copper-containing silica". Himia, Fizika ta Tehnologia Poverhni 13, n. 3 (30 settembre 2022): 274–88. http://dx.doi.org/10.15407/hftp13.03.274.

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A series of polymeric composites based on polyurethanes with copolymer fragments of poly(vinyl butyral-vinyl acetate-vinyl alcohol) and 1,6-hexamethylenediamine filled with modified precipitated silica were synthesized. The content of silver in the nanocomposites was 0.1–0.2 and of copper – 0.14 and 0.2 mmol per 1 g of SiO2 (02AgCu; AgCu and 01Ag samples). The content of silver-containing silica filler in the polymer composites was 0.1, 0.5 and 1.0 wt. %. By means of the IR spectroscopy, it has been found that a physical immobilization of modified silica in the polymeric matrix takes place due to the presence of intermolecular hydrogen bonds. The influence of fillers on the structure and properties of polymer materials, in particular, on thermophysical properties and physico-mechanical parameters (tensile strength and relative elongation at rupture), were investigated. The results of physico-mechanical tests indicate that the strength characteristics of polyurethane depend on the content and concentration of fillers. It has been found that the polymeric sample filled with 02AgCu nanocomposite (0.2 mmol of Ag and Cu per 1 g of SiO2) has the highest strength of the rupture. It has been shown that the introduction of modified silica leads to a reduction of relative elongation at rupture of polymeric nanocomposite. The highest values showed the sample filled with AgCu (0.1 and 0.12 mmol Ag and Cu, respectively, per 1 g of SiO2). The introduction of silver-containing silica nanocomposites into a polyurethane, containing polyvinylbutiral copolymer fragments, leads to an increase in tensile strength and reduction of relative elongation at rupture. Polymeric composite with 0.5 wt. % of filler had the highest values of physico-mechanical parameters. It has been shown that the thermosphysical characteristics depend on the concentration and composition of the fillers and have a nonlinear character. The synthesized nanocomposites can be effectively used as biomedical materials.

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22

Mačák, Lívia, Oksana Velgosova, Erika Múdra, Marek Vojtko, Silvia Dolinská e František Kromka. "Preparation of Green Silver Nanoparticles and Eco-Friendly Polymer–AgNPs Nanocomposites: A Study of Toxic Properties across Multiple Organisms". Polymers 16, n. 13 (29 giugno 2024): 1865. http://dx.doi.org/10.3390/polym16131865.

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This article focuses on the eco-friendly (green) synthesis of silver nanoparticles (AgNPs) and their incorporation into a polymer matrix. For AgNPs synthesis, Lavandula angustifolia (lavender) leaf extract was used as a reducing and stabilizing agent, and as a silver precursor, AgNO3 solution with different concentrations of silver (50, 100, 250, and 500 mg/L) was used. Prepared AgNPs colloids were characterized using UV–vis spectrophotometry, transmission electron microscopy (TEM), and X-ray diffraction (XRD). The spherical morphology of AgNPs with an average size of 20 nm was confirmed across all samples. Further, the antimicrobial properties of the AgNPs were evaluated using the disk diffusion method on algae (Chlorella kessleri) and the well diffusion method on bacteria (Staphylococcus chromogenes, Staphylococcus aureus, and Streptococcus uberis), along with root growth inhibition tests on white mustard (Sinapis alba). Polymer composite (PVA–AgNPs) was prepared by incorporation of AgNPs into the polymer matrix. Subsequently, non-woven textiles and thin foils were prepared. The distribution of AgNPs within the nanocomposites was observed by scanning electron microscopy (SEM). Antibacterial properties of PVA–AgNPs composites were analyzed on bacteria Streptococcus uberis. It was found that not only AgNPs showed good antimicrobial properties, but toxic properties were also transferred to the PVA–AgNPs nanocomposite.

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23

Telipan, Gabriela, Lucian Pîslaru-Dănescu, Eduard-Marius Lungulescu, Ioana Ion e Virgil Marinescu. "A Comparative Study of Polypyrrole and Ag/Polypyrrole Hybrid Nanocomposites as Sensitive Material Used for New Dry Polarizable Bioimpedance Sensors". Applied Sciences 11, n. 9 (2 maggio 2021): 4168. http://dx.doi.org/10.3390/app11094168.

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Abstract (sommario):

Three types of dry polarizable electric bioimpedance sensor for skin bioimpedance monitoring without skin preparation have been developed. The sensitive materials as a component of these sensors are the conductive polypyrrole and hybrid nanocomposite polypyrrole-Ag, with 10% and 20% Ag incorporated in the polypyrrole matrix. The hybrid nanocomposites Ag nanoparticles (NPs)/polypyrrole were obtained by introducing the colloid solution of Ag NPs in pyrrole solution, followed by polymerisation, and calculated for 10% and 20% of monomer’s mass. The structural characterisation and morphological analysis of these sensitive materials were carried-out by Raman spectrometry, Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. In making the electrodes, the technique of pressing powders of polypyrrole and hybrid composites Ag NPs/polypyrrole in a hydraulic press was used in the form of a disk. The electric bioimpedance performance of sensors was investigated using a two-point method in the frequency range of 1–300 kHz, at a voltage of 2 Vpeak-peak, on six human subjects, three men and three women. For these three bioimpedance sensors, it was found that the electric bioimpedance of the skin decreases across the frequency range and shows good linearity of the impedance-frequency curve on the range frequency of interest in bioimpedance measurements.

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24

Fernández-Álvarez, Fátima, Gracia García-García e José L. Arias. "A Tri-Stimuli Responsive (Maghemite/PLGA)/Chitosan Nanostructure with Promising Applications in Lung Cancer". Pharmaceutics 13, n. 8 (10 agosto 2021): 1232. http://dx.doi.org/10.3390/pharmaceutics13081232.

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Abstract (sommario):

A (core/shell)/shell nanostructure (production performance ≈ 50%, mean diameter ≈ 330 nm) was built using maghemite, PLGA, and chitosan. An extensive characterization proved the complete inclusion of the maghemite nuclei into the PLGA matrix (by nanoprecipitation solvent evaporation) and the disposition of the chitosan shell onto the nanocomposite (by coacervation). Short-term stability and the adequate magnetism of the nanocomposites were demonstrated by size and electrokinetic determinations, and by defining the first magnetization curve and the responsiveness of the colloid to a permanent magnet, respectively. Safety of the nanoparticles was postulated when considering the results from blood compatibility studies, and toxicity assays against human colonic CCD-18 fibroblasts and colon carcinoma T-84 cells. Cisplatin incorporation to the PLGA matrix generated appropriate loading values (≈15%), and a dual pH- and heat (hyperthermia)-responsive drug release behaviour (≈4.7-fold faster release at pH 5.0 and 45 °C compared to pH 7.4 and 37 °C). The half maximal inhibitory concentration of the cisplatin-loaded nanoparticles against human lung adenocarcinoma A-549 cells was ≈1.6-fold less than that of the free chemotherapeutic. Such a biocompatible and tri-stimuli responsive (maghemite/PLGA)/chitosan nanostructure may found a promising use for the effective treatment of lung cancer.

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25

HUTH, CHRISTOPHER, DONGLU SHI, FENG WANG, DONALD CARRAHAR, JIE LIAN, FENGYUAN LU, JIAMING ZHANG, RODNEY C. EWING e GIOVANNI M. PAULETTI. "PHOSPHOLIPID ASSEMBLY ON SUPERPARAMAGNETIC NANOPARTICLES FOR THERMORESPONSIVE DRUG DELIVERY APPLICATIONS". Nano LIFE 01, n. 03n04 (settembre 2010): 251–61. http://dx.doi.org/10.1142/s1793984410000237.

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Thermoresponsive nanocomposites were prepared by immobilizing a 2–3 nm thick phospholipid layer on the surface of superparamagnetic Fe3O4 nanoparticles via high-affinity avidin/biotin interactions. Morphological and physicochemical surface properties were assessed using transmission electron microscopy, confocal laser scanning microscopy, differential scanning calorimetry, and attenuated total reflectance Fourier transform infrared spectroscopy. The zeta potential of Fe3O4 colloids in phosphate buffered saline (PBS) decreased from -23.6 to -5.0 mV as a consequence of phospholipid immobilization. Nevertheless, heating properties of these superparamagnetic nanoparticles within an alternating magnetic field were not significantly affected. Hyperthermia-relevant temperatures > 40°C were achieved within 10–15 min using a 7-mT magnetic field alternating at a frequency of 1 MHz. Loading of the surface-associated phospholipid layer with the hydrophobic dye dansylcadaverine was accomplished at an efficiency of 479 ng/mg Fe3O4 . Release of this drug surrogate was temperature-dependent, resulting in a 2.5-fold greater release rate when nanoparticles were exposed to a temperature above the experimentally determined melting temperature of 39.7°C. These data underline the feasibility of preparing novel, stimulus-induced drug delivery systems where payload release from a colloid-immobilized phospholipid assembly is triggered by hyperthermia.

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26

Serkhacheva, N. S., N. I. Prokopov, A. Yu Gerval'd, N. A. Lobanov e I. A. Gritskova. "The Heterophase Polymerisation of Styrene in the Presence of Zinc Oxide Nanoparticles". International Polymer Science and Technology 44, n. 10 (ottobre 2017): 13–18. http://dx.doi.org/10.1177/0307174x1704401003.

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Heterophase polymerisation of styrene was carried out, and nanocomposite polystyrene microspheres with a controllable content of ZnO nanoparticles were synthesised. The colloid chemical properties of the obtained polymer suspensions were studied, and it was shown that the particles have a ‘core–shell’ structure with a ZnO content of up to 30%.

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27

Liu, Qing Hong, Xia Yin Yao e Zhao Ping Liu. "Single Layer Graphene Oxide Sheets-Epoxy Nanocomposites with Greatly Improved Mechanical and Thermal Properties". Advanced Materials Research 391-392 (dicembre 2011): 175–79. http://dx.doi.org/10.4028/www.scientific.net/amr.391-392.175.

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The single layer graphene oxide (GO) sheets-epoxy nanocomposites were prepared by directly dispersing concentrated GO aqueous colloid into dimethylformamide (DMF), and then incorporating the mixed solution into epoxy resin. The mechanical and thermal properties of the as-prepared nanocomposites were investigated by Notched Izod impact tests and thermogravimetric analysis. Significant improvements in both impact strength and thermal properties were observed for the nanocomposites at very low level of GO loading content. The impact strength of the nonacomposites containing 0.15 wt% GO was 10.66±0.75 MPa, which was 165.84 % higher than that of the pure epoxy resin (4.01±0.52 MPa). The decomposition temperature of the nanocomposites containing 0.3 wt % GO increased about 12 °C. The effective reinforcement of the GO based epoxy nanocomposites can be attributed to the good dispersion and the strong interfacial interactions between the GO sheets and the epoxy resin matrices.

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Devi, Rooma, Sandeep Yadav e C. S. Pundir. "Au-colloids–polypyrrole nanocomposite film based xanthine biosensor". Colloids and Surfaces A: Physicochemical and Engineering Aspects 394 (gennaio 2012): 38–45. http://dx.doi.org/10.1016/j.colsurfa.2011.11.021.

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29

Pyun, Jeffrey. "Nanocomposite Materials from Functional Polymers and Magnetic Colloids". Polymer Reviews 47, n. 2 (aprile 2007): 231–63. http://dx.doi.org/10.1080/15583720701271294.

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30

Zulina, N. A., U. S. Achor e K. I. Kniazev. "Polymer composition influence on optical properties of laser-generated Au nanoparticles based nanocomposites". Физика и техника полупроводников 52, n. 5 (2018): 503. http://dx.doi.org/10.21883/ftp.2018.05.45847.36.

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Abstract (sommario):

AbstractAu nanoparticles (AuNPs) stable colloid solution were prepared by laser ablation and fragmentation in liquid monomer isodecyl acrylate (IDA). Sizes of obtained nanoparticles were determined by scanning transmission electron microscopy (STEM) and were about 20 nm. Nanocomposites films were prepared from obtained stable colloid solution by UV-photocuring. To prepare solid polymer films different crosslinking diacrylates were used. Third-order nonlinear optical responses of prepared nanomaterials with different polymer matrix compositions were estimated by z-scan technique and compared.

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31

LEE, SEUNG-CHUL, SANG-WHA LEE e IK-JOONG KANG. "PREPARATION AND CHARACTERIZATION OF CHITOSAN–GOLD NANOCOMPOSITES FOR DRUG DELIVERY APPLICATION". Surface Review and Letters 17, n. 02 (aprile 2010): 165–72. http://dx.doi.org/10.1142/s0218625x10013643.

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Abstract (sommario):

Chitosan–gold nanocomposites were fabricated via a seed-mediated goldshell growth over chitosan–gold nanocomplex and examined as a potential biomedical agent for drug delivery. Chitosan–gold nanocomplex was formed by the electrostatic interaction between of cationic chitosan nanoparticles (ca. 50 nm) and anionic gold colloids (ca. 1–3 nm) and the subsequent reduction of gold salts was conducted to form the gold clusters over the chitosan nanoparticles in the presence of reducing ascorbic acid. The resultant nanocomposites (or nanoshells) exhibited the absorption peak around 580 nm that was clearly red-shifted by ca. 60 nm as compared to gold nanoparticles. Surface morphology and plasmonic properties of chitosan–gold nanocomposites were characterized by transmission electron microscopy, field emission scanning electron microscopy (including EDX), ultraviolet–visible spectroscopy, and zeta-potential meter.

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32

Mitzscherling, S., Q. Cui, W. Koopman e M. Bargheer. "Dielectric function of two-phase colloid–polymer nanocomposite". Physical Chemistry Chemical Physics 17, n. 44 (2015): 29465–74. http://dx.doi.org/10.1039/c5cp04326c.

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33

Vinogradov, Alexandr V., A. A. Levshanov, M. A. Kashirin, A. V. Agafonov e Vladimir V. Vinogradov. "Magneto-Optical Modulation on Colloid Cu–Ni Nanocomposite". Journal of Physical Chemistry C 119, n. 3 (12 gennaio 2015): 1500–1505. http://dx.doi.org/10.1021/jp511736f.

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34

Marzi, Daniela, Christos N. Likos e Barbara Capone. "Coarse graining of star-polymer – colloid nanocomposites". Journal of Chemical Physics 137, n. 1 (7 luglio 2012): 014902. http://dx.doi.org/10.1063/1.4730751.

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35

Fahmy, Alaa, Wael H. Eisa, Mohamed Yosef e Ali Hassan. "Ultra-Thin Films of Poly(acrylic acid)/Silver Nanocomposite Coatings for Antimicrobial Applications". Journal of Spectroscopy 2016 (2016): 1–11. http://dx.doi.org/10.1155/2016/7489536.

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Abstract (sommario):

In this work not only colloids of poly(acrylic acid) (PAA) embedded with silver nanoparticles (Ag-NPs) but thin films (10 nm) also were deposited using electrospray deposition technique (ESD). A mixture of sodium borohydride (NaBH4) and ascorbic acid (AA) were utilized to reduce the silver ions to generate Ag-NPs in the PAA matrix. Moreover, sodium tricitrate was used to stabilize the prepared colloids. The obtained colloids and films were characterized using UV-visible, transmission electron microscopy (TEM). UV-Vis results reveal that an absorption peak at 425 nm was observed in presence of PAA-AgNO3-AA-citrate-NaBH4. This peak is attributed to the well-known surface plasmon resonance of the silver bound in Ag-NPs, while the reduction was rendering and/or inhibiting in absence of the AA and citrate. FTIR spectroscopy was used to study the mechanism of the reaction process of silver nitrate with PAA. TEM images showed the well dispersion of Ag-NPs in the PAA matrix with average particle size of 8 nm. The antimicrobial studies showed that the Ag-NPs embedded in the PAA matrix have proven to have a significant antimicrobial activity againstE. coli,B. subtilis, andC. albicans.

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36

Bashir, Sajid, James Dinn e Jingbo Liu. "Three Waves of Disinfectants to Inactivate Bacteria". MRS Proceedings 1498 (2013): 91–96. http://dx.doi.org/10.1557/opl.2013.331.

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Abstract (sommario):

ABSTRACTMetallic silver nanoparticles (NPs) have extensively been used in the treatment of disease and purification and heralded the ‘first wave’ of disinfection science, the ‘second wave’ being the nanocomposite of metal-doped TiO2. Recent advances in engineered surfaces have enabled ultrahigh surface area and rapid sterilization via using metal-organic frameworks (MOFs) as the ‘third wave’ disinfectant. MOFs offer the same advantages as colloids but also have ultra high surface area, long term persistence and ultra low doses, applied for water purification.

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Garcia, Maurie E., Lane A. Baker e Richard M. Crooks. "Preparation and Characterization of Dendrimer−Gold Colloid Nanocomposites". Analytical Chemistry 71, n. 1 (gennaio 1999): 256–58. http://dx.doi.org/10.1021/ac980588g.

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38

Massironi, Alessio, Albina Ribeiro Franco, Pedro Sousa Babo, Dario Puppi, Federica Chiellini, Rui L. Reis e Manuela Estima Gomes. "Development and Characterization of Highly Stable Silver NanoParticles as Novel Potential Antimicrobial Agents for Wound Healing Hydrogels". International Journal of Molecular Sciences 23, n. 4 (15 febbraio 2022): 2161. http://dx.doi.org/10.3390/ijms23042161.

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Abstract (sommario):

Recurrent microbial infections are a major cause of surgical failure and morbidity. Wound healing strategies based on hydrogels have been proposed to provide at once a barrier against pathogen microbial colonization, as well as a favorable environment for tissue repair. Nevertheless, most biocompatible hydrogel materials are more bacteriostatic than antimicrobial materials, and lack specific action against pathogens. Silver-loaded polymeric nanocomposites have efficient and selective activity against pathogenic organisms exploitable for wound healing. However, the loading of metallic nanostructures into hydrogels represents a major challenge due to the low stability of metal colloids in aqueous environments. In this context, the aim of the present study was the development of highly stable silver nanoparticles (AgNPs) as novel potential antimicrobial agents for hyaluronic acids hydrogels. Two candidate stabilizing agents obtained from natural and renewable sources, namely cellulose nanocrystals and ulvan polysaccharide, were exploited to ensure high stability of the silver colloid. Both stabilizing agents possess inherent bioactivity and biocompatibility, as well as the ability to stabilize metal nanostructures thanks to their supramolecular structures. Silver nitrate reduction through sodium borohydride in presence of the selected stabilizing agents was adopted as a model strategy to achieve AgNPs with narrow size distribution. Optimized AgNPs stabilized with the two investigated polysaccharides demonstrated high stability in phosphate buffer saline solution and strong antimicrobial activity. Loading of the developed AgNPs into photocrosslinked methacrylated hyaluronic acid hydrogels was also investigated for the first time as an effective strategy to develop novel antimicrobial wound dressing materials.

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Maeda, Shuichi, e Steven P. Ames. "Preparation and Characterization of Polypyrrole-Tin(IV) Oxide Nanocomposite Colloids". Chemistry of Materials 7, n. 1 (gennaio 1995): 171–78. http://dx.doi.org/10.1021/cm00049a026.

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Gianini, Michel, Walter R. Caseri e Ulrich W. Suter. "Polymer Nanocomposites Containing Superstructures of Self-Organized Platinum Colloids". Journal of Physical Chemistry B 105, n. 31 (agosto 2001): 7399–404. http://dx.doi.org/10.1021/jp004304j.

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41

Wang, Xiao-Song, Tanapak Metanawin, Xian-Yu Zheng, Pei-Yi Wang, Mannan Ali e David Vernon. "Structure-Defined C60/Polymer Colloids Supramolecular Nanocomposites in Water". Langmuir 24, n. 17 (2 settembre 2008): 9230–32. http://dx.doi.org/10.1021/la801968x.

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42

Cheng, Zheng Dong, Min Shuai, Andres Mejia, Hua Wei Li, Zeng Kai Shi, Jiao Yan Ai, Wei Zhou e Ying Chen. "Disk-Shaped Colloids: The Synthesis and Applications of ZrP Crystals". Advanced Materials Research 787 (settembre 2013): 177–83. http://dx.doi.org/10.4028/www.scientific.net/amr.787.177.

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Abstract (sommario):

We performed systematic experiments on the synthesis of layered crystal α-ZrP and revealed the control of size, aspect ratio and size polydispersity of disk-shaped crystals. The growth of the disks is mediated by oriented attachment, taking place continuously throughout the hydrothermal treatment between various sized disks. The master of the synthesis of layered crystals will contribute to various applications such as the nanocomposites and liquid crystals.

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Yang, Kui, Chang Hui Yang e Zhen Li. "Synthesis and Characterization of PVA/MMT Porous Nanocomposite Prepared by Directional Freeze-Drying Method". Advanced Materials Research 197-198 (febbraio 2011): 253–60. http://dx.doi.org/10.4028/www.scientific.net/amr.197-198.253.

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Abstract (sommario):

Porous PVA/MMT nanocomposites, which included a great deal of macroporous, mesoporous and a few micorporous were fabricated by directional freezing and freeze-drying. X-ray diffraction (XRD), Scan Electric Microscope (SEM), Fourier Transform Infrared (FT-IR) spectroscopy, and Thermo gravimetric-differential scanning calorimeter analysis (TG-DSC) were used characterize the samples. Results showed that the morphology and the interactions between MMT and PVA of the obtained porous nanocomposites were influenced by nanoparticle size, colloid concentration , aging time etc.O-H bond in PVA and Si-O bond in MMT, "acetate" in PVA and O-H bond in particle flat of MMT which occurred coupling constituted hydrogen bonding which enhanced the driving power to help PVA molecules insert into interlayer spaces of MMT.

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Zubair, Muhammad, Muhammad Shahid Rafique, Afshan Khalid, Tahir Yaqub, Suliman Yousef Alomar e Huma Gohar. "Synthesis of Gold-PVP Nanostructured Composites by Microplasma: A Test to Study Their Inhibiting Tendency of Avian Influenza Virus Activity". Applied Sciences 12, n. 11 (25 maggio 2022): 5352. http://dx.doi.org/10.3390/app12115352.

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Abstract (sommario):

Gold–polymer nanostructured composites have a great potential in the biomedical and advanced materials field as an antimicrobial agent against various pathogens, especially viruses. In the present work, gold and gold-PVP colloids have been prepared by the electrochemical reduction of hydrogen tetrachlorauric acid (HAuCl4·3H2O) precursor. The atmospheric pressure microplasma technique was used as a reducing agent, while D-Fructose was used as a stabilizing agent in the synthesis process. X-ray Diffraction (XRD) confirmed the crystalline behavior of both gold nanostructured particles and gold-PVP nanocomposites. The morphology of the nanoparticles was examined by SEM. The absorption characteristic peaks at 541 nm and 542 nm in UV-Vis spectra confirmed the surface plasmon resonance in gold nanostructured particles and gold-PVP nanostructured composites, respectively. Dynamic light scattering studies with percentage intensity distribution revealed particle size distribution ranges from 8–288 nm for gold colloids and 15–297 nm for gold-PVP colloids. Gold-PVP nanostructured composites have shown an improvement in the antiviral activity against the H9N2 virus as compared to bare gold nanostructured particles.

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45

Alhabill, F. N., A. S. Vaughan e T. Andritsch. "On nanocomposite fabrication: using rheology to characterize filler/polymer interactions in epoxy-based nanocomposites". Materials Today Chemistry 22 (dicembre 2021): 100559. http://dx.doi.org/10.1016/j.mtchem.2021.100559.

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46

Gulina, L. B., V. P. Tolstoi e K. B. Semishchenko. "Layers of nanocomposite FeOOH-xH3PW12O40 synthesized by ion-colloid layering". Russian Journal of Applied Chemistry 83, n. 1 (gennaio 2010): 151–53. http://dx.doi.org/10.1134/s1070427210010283.

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47

Sportelli, Maria C., Antonio Ancona, Rosaria A. Picca, Adriana Trapani, Annalisa Volpe, Giuseppe Trapani e Nicola Cioffi. "Laser Ablation Synthesis in Solution of Nanoantimicrobials for Food Packaging Applications". MRS Proceedings 1804 (2015): 37–42. http://dx.doi.org/10.1557/opl.2015.611.

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Abstract (sommario):

ABSTRACTDesigning bioactive materials, with controlled metal ion release, exerting significant bioactivity and associated low toxicity for humans, is nowadays one of the most important challenges for the scientific community. In this work, we propose a new material combining the well-known antimicrobial properties of copper nanoparticles (CuNPs) with those of bioactive chitosan (CS), a cheap natural polymer widely exploited for its biodegradability and nontoxicity. Here, we used ultrafast femtosecond laser pulses to finely fragment, via laser ablation, a Cu solid target immersed into aqueous CS solutions. Homogeneously dispersed copper-chitosan (Cu-CS) colloids were obtained by tuning the Cu/CS molar ratios, according to the initial chitosan concentration, as well as other experimental parameters. Cu-CS colloids were characterized by several techniques, like UV-Vis and X-ray Photoelectron spectroscopies (XPS). Transmission Electron Microscopy (TEM) was used to morphologically characterize the novel nanocomposites.

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Colver, Patrick J., Catheline A. L. Colard e Stefan A. F. Bon. "Multilayered Nanocomposite Polymer Colloids Using Emulsion Polymerization Stabilized by Solid Particles". Journal of the American Chemical Society 130, n. 50 (17 dicembre 2008): 16850–51. http://dx.doi.org/10.1021/ja807242k.

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49

L, Priya. "Synthesis and Characterization of Photoluminescent PVA/ZnS: Mn2+ Nanocomposites". Mapana - Journal of Sciences 12, n. 1 (22 gennaio 2013): 31–37. http://dx.doi.org/10.12723/mjs.24.4.

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Abstract (sommario):

A ZnS nanoparticle doped with Mn2+ is synthesized in aqueous media and PVA using chemical co-precipitation method. This colloid was analyzed using uv-vis spectrophotometry. It is observed that the absorption peak blue shifts as compared to the bulk absorption of ZnS suggesting the nanoparticle formation. The energy gaps of these nanoparticles were calculated from the uv-vis spectra. The average particle size analysis is carried out using XRD. Photoluminescence of PVA/ ZnS:Mn2+ is studied. It is observed that the composite sample exhibits an orange emission peak as is reported for pure ZnS: Mn2+.

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Varesano, Alessio, Claudia Vineis, Cinzia Tonetti, Diego Ramirez, Giorgio Mazzuchetti, Simona Ortelli, Magda Blosi e Anna Costa. "Multifunctional Hybrid Nanocomposite Nanofibers Produced by Colloid Electrospinning from Water Solutions". Current Nanoscience 11, n. 1 (1 dicembre 2014): 41–48. http://dx.doi.org/10.2174/1573413710666140922225056.

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