Articles de revues : « Colloidal synthesi »

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Cademartiri, Ludovico, et Geoffrey A. Ozin. « Emerging strategies for the synthesis of highly monodisperse colloidal nanostructures ». Philosophical Transactions of the Royal Society A : Mathematical, Physical and Engineering Sciences 368, n^o 1927 (28 septembre 2010) : 4229–48. http://dx.doi.org/10.1098/rsta.2010.0126.

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This short perspective describes recent developments in the synthesis of nanoscale colloids from sparingly soluble precursors. These strategies, which we dubbed ‘heterogeneous nanocrystal syntheses’ owing to the presence of a precursor in a non-colloidal solid state, have demonstrated the ability to generate new colloidal shapes, a superior monodispersity and a remarkable ability to delay the onset of Ostwald ripening, when compared with more traditional and purely colloidal strategies. We review the key contributions to this emerging area of research and discuss in detail the remarkable number of differences between these syntheses and the widely used homogeneous organometallic syntheses for making nanoscale colloids.

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Schmid, Günter, Andreas Lehnert, Ulrich Kreibig, Zbignew Adamczyk et Peter Belouschek. « Synthese und elektronenmikroskopische Untersuchung kontrolliert gewachsener, ligandstabilisierter Goldkolloide sowie theoretische Überlegungen zur Oberflächenbelegung durch Kolloide / Synthesis and Electron Microscopic Investigation of Controlled Grown, Ligand Stabilized Gold Colloids and Theoretical Considerations on the Covering of Surfaces by Colloids ». Zeitschrift für Naturforschung B 45, n^o 7 (1 juillet 1990) : 989–94. http://dx.doi.org/10.1515/znb-1990-0713.

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18 nm Gold colloids are used as seeds for a controlled growth of 36 nm colloids which are then stabilized by P(m-C6H4SO3Na)3. These colloids can be isolated as golden leaflets and are readily soluble in water in virtually any concentration. Electron microscopic investigations prove a very small particle size distribution. X-ray powder diffraction and molecular weight determinations support the results of the electron microscopic investigations. The distance between the colloidal particles in two-dimensional layers corresponds to double-layers of phosphane ligands around each colloid, twice 1.2 nm. Isolated colloids seem to possess thicker ligand shells. A single 44 nm colloid shows a corona of about 7.2 nm thickness, corresponding to 12 phosphane layers. A quantitative description of two-dimensional packing densities is suggested using a novel theoretical model. By means of Monte Carlo simulations the two-dimensional structures are formed during the covering of supports of different geometry can be calculated.

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Nikishina, Maria B., Evgenia V. Ivanova, Yury M. Atroschenko, Irina V. Shahkeldyan, Igor V. Blohin, Loik G. Mukhtorov, Konstantin I. Kobrakov et Georgy V. Pestsov. « Biological activity of colloidal solutions of silver, obtained by means of sálix cáprea extract ». Butlerov Communications 60, n^o 10 (31 octobre 2019) : 54–59. http://dx.doi.org/10.37952/roi-jbc-01/19-60-10-54.

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The presented publication is devoted to the study of the biological activity of silver colloids synthesized based on extracts obtained from various parts of the goat willow plant (Sálix cáprea). The ability of colloidal silver solutions of various concentrations to stimulate growth processes in wheat seeds at the germination stage is analyzed. The effect of colloidal solutions on the catalytic effect of amylase was studied. The fungicidal activity of synthesized silver particles was studied. For the study, colloidal silver particles were obtained by the "green synthesis" method. Extracts of goat willow bark, leaves and buds of varying degrees of dilution were used as a reducing agent. The analysis of sugar content and pH of solutions of plant extracts before and after colloid formation was carried out in order to establish the participation of sugars and acids in the process of silver recovery. The biological activity of colloids was analyzed on the seeds of winter wheat cultivar "Moskovskaya-39". The germination energy of wheat seeds was determined on the 3rd day after sowing by counting the germinated seeds. Amylase activity was measured in the roots and shoots of wheat plants by the amount of undecomposed starch by spectrophotometry. Fungicidal activity was studied with respect to fungi: F. moniliforme, F. oxysporum, S. sclerotiorum, V. inaequalis, R. solani, B. sorokiniana, P. ostreatus. The data obtained show that the sugars that make up the initial extracts of various parts of goat willow are completely consumed in the process of silver recovery and the formation of colloidal particles. A change in the acid content at the stage of colloid formation does not allow us to draw an unambiguous conclusion about the mechanism of participation of these compounds in the process of colloid formation. A study of the biological activity of synthesized silver colloids showed their high ability to stimulate growth processes in wheat seeds. A study of enzymatic catalysis also shows, in general, the positive effect of silver colloids on amylase activity within 1 minute of the starch hydrolysis reaction. An analysis of the data obtained in the study of fungistaticity suggests that silver colloids obtained in extracts from leaves, bark and willow inflorescences exhibit high fungicidal activity against F. moniliforme, S. sclerotiorum, P. ostreatus and B. sorokiniana.

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Valverde-Alva, Miguel A., Jhenry F. Agreda-Delgado, Juan A. Vega-González, Juan C. Rodríguez-Soto, Julio C. Idrogo-Córdova, Luis M. Angelats-Silva et Claver W. Aldama-Reyna. « Effect of the magnetic field on the synthesis of colloidal silver and gold nanoparticles by laser ablation in bidestilated water ». MOMENTO, n^o 63 (9 juillet 2021) : 1–11. http://dx.doi.org/10.15446/mo.n63.91515.

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The effect of magnetic field of 0.3 T on the concentration, distribution of sizes in suspension and zeta potential of colloidal gold and colloidal silver nanoparticles, obtained by considering the pulsed laser ablation in double distilled water was studied. The magnetic field was transverse to the direction of incidence of the laser radiation and parallel to the surface of a submerged target. An Nd: YAG laser was used (1064 nm in wavelength, 10 ns in duration, repetition rate of 10 Hz and 37 mJ of energy) to ablate targets. The colloids were characterized by inductively coupled plasma optical emission spectroscopy, ultraviolet-visible spectroscopy, dynamic light scattering and zeta potential. Concentration analysis suggested that applying magnetic field of 0.3 T during nanoparticle synthesis leads to higher concentration. Applying magnetic field led to an eleven percent increase in the concentration of the colloid with gold nanoparticles and a five percent increase in the concentration of the colloidal silver nanoparticles. The absorption spectra suggested the presence of spherical nanoparticles. When analyzing the effect of the magnetic field on the hydrodynamic size distribution of the nanoparticles and the zeta potential of the colloids, no significant changes were evidenced. The magnetic confinement of the plasma induced by laser ablation caused changes in the characteristics of the colloids.

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Goncharov, Victor, Konstantin Kozadaev et Dzmitry Shchehrykovich. « Investigation of Noble Metals Colloidal Systems Formed by Laser Synthesis at Air ». Advances in Optical Technologies 2012 (8 juillet 2012) : 1–5. http://dx.doi.org/10.1155/2012/907292.

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The present work is dedicated to the development of formation and diagnostics methods of water colloids of noble metals (Au, Au, Pt). As anoble nanoparticles formation method, the laser synthesis at air conditions is proposed. By the implantation of noble nanoparticles into water media, the colloidal systems of noble metals can be obtained. For the aims of investigation of noble colloid parameters, the complex diagnostics method is used. Such approach deals with direct methods (scanning electron microscopy and the characteristic radiation registration) and indirect methods (absorption spectroscopy and extinction modeling by Mie theory).

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Kendall, Owen, Pierce Wainer, Steven Barrow, Joel van Embden et Enrico Della Gaspera. « Fluorine-Doped Tin Oxide Colloidal Nanocrystals ». Nanomaterials 10, n^o 5 (30 avril 2020) : 863. http://dx.doi.org/10.3390/nano10050863.

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Fluorine-doped tin oxide (FTO) is one of the most studied and established materials for transparent electrode applications. However, the syntheses for FTO nanocrystals are currently very limited, especially for stable and well-dispersed colloids. Here, we present the synthesis and detailed characterization of FTO nanocrystals using a colloidal heat-up reaction. High-quality SnO2 quantum dots are synthesized with a tuneable fluorine amount up to ~10% atomic, and their structural, morphological and optical properties are fully characterized. These colloids show composition-dependent optical properties, including the rise of a dopant-induced surface plasmon resonance in the near infrared.

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Susilowati, Endang, Triyono Triyono, Sri Juari Santosa et Indriana Kartini. « Synthesis of Silver-Chitosan Nanocomposites Colloidal by Glucose as Reducing Agent ». Indonesian Journal of Chemistry 15, n^o 1 (30 mars 2015) : 29–35. http://dx.doi.org/10.22146/ijc.21220.

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Silver-chitosan nanocomposites colloidal was successfully performed by chemical reduction method at room temperature using glucose as reducing agent, sodium hydroxide (NaOH) as accelerator reagent, silver nitrate (AgNO3) as metal precursor and chitosan as stabilizing agent. Compared to other synthetic methods, this work is green and simple. The effect of the amount of NaOH, molar ratio of AgNO3 to glucose and AgNO3 concentration towards Localized Surface Plasmon Resonance (LSPR) absorption band of silver nanoparticles was investigated using UV-Vis spectrophotometer. The stability of the colloid was also studied for the first 16 weeks of storage at ambient temperature. The formation of silver nanoparticles was confirmed by the appearance of LSPR absorption peak at 402.4–414.5 nm. It is also shown that the absorption peak of LSPR were affected by NaOH amount, ratio molar AgNO3/glucose and concentration of AgNO3. The produced silver nanoparticles were spherical with dominant size range of 6 to 18 nm as shown by TEM images. All colloidals were stable without any aggregation for 16 weeks after preparation. The newly prepared silver-chitosan nanocomposites colloidal may have potential for antibacterial applications.

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Tian, Lei, Yanxing Liu, Dai Wang, Jiji Tan, Yankun Xie, Bei Li, Qiuyu Zhang, Caizhen Zhu et Jian Xu. « Particle-click-particle : colloidal clusters from click seeded emulsion polymerization ». Polymer Chemistry 13, n^o 8 (2022) : 1084–89. http://dx.doi.org/10.1039/d1py00360g.

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Pascu, Bogdan, Adina Negrea, Mihaela Ciopec, Corneliu Mircea Davidescu, Petru Negrea, Vasile Gherman et Narcis Duteanu. « New Generation of Antibacterial Products Based on Colloidal Silver ». Materials 13, n^o 7 (29 mars 2020) : 1578. http://dx.doi.org/10.3390/ma13071578.

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The main objective of the present paper is the green synthesis of colloidal silver by ultrasonication starting from silver nitrate and using soluble starch as the reducing agent. Soluble starch has been used during synthesis because it is a cheap and environmentally friendly reactive. Silver colloid has been characterized by physicochemical methods: UV–VIS spectroscopy, Scanning Electron Microscopy and Energy Dispersive X-Ray spectroscopy. This colloidal material was prepared in order to prove and establish its toxicity on heterotrophic bacteria. Toxicity tests were carried out using test cultures with and without silver colloid with different concentrations. This way was possible to establish the minimum silver concentration that presents a toxic effect against used bacteria. Quantitative evaluation of bacterial growth was performed by using the Most Probable Number method. By counting the bacterial colony number, the antibacterial effect was determined for colloidal silver deposited onto the cotton gauze by adsorption. During the present study, we optimized the adsorption specific parameters: solid:liquid ratio, temperature, contact time, colloidal silver concentration. By thermodynamic, equilibrium and kinetic studies, the adsorptive process mechanism was established.

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Stiufiuc, Rares, Cristian Iacovita, Raul Nicoara, Gabriela Stiufiuc, Adrian Florea, Marcela Achim et Constantin M. Lucaciu. « One-Step Synthesis of PEGylated Gold Nanoparticles with Tunable Surface Charge ». Journal of Nanomaterials 2013 (2013) : 1–7. http://dx.doi.org/10.1155/2013/146031.

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The present work reports a rapid, simple and efficient one-step synthesis and detailed characterisation of stable aqueous colloids of gold nanoparticles (AuNPs) coated with unmodified poly(ethylene)glycol (PEG) molecules of different molecular weights and surface charges. By mixing and heating aqueous solutions of PEG with variable molecular chain and gold(III) chloride hydrate (HAuCl4) in the presence of NaOH, we have successfully produced uniform colloidal 5 nm PEG coated AuNPs of spherical shape with tunable surface charge and an average diameter of 30 nm within a few minutes. It has been found out that PEGylated AuNPs provide optical enhancement of the characteristic vibrational bands of PEG molecules attached to the gold surface when they are excited with both visible (532 nm) and NIR (785 nm) laser lines. The surface enhanced Raman scattering (SERS) signal does not depend on the length of the PEG molecular chain enveloping the AuNPs, and the stability of the colloid is not affected by the addition of concentrated salt solution (0.1 M NaCl), thus suggesting their potential use forin vitroandin vivoapplications. Moreover, by gradually changing the chain length of the biopolymer, we were able to control nanoparticles’ surface charge from −28 to −2 mV, without any modification of the Raman enhancement properties and of the colloidal stability.

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Bolotov, Alexander N., Vladislav V. Novikov et Olga O. Novikova. « ON DEPENDENCE OF COLLOIDAL STABILITY OF MAGNETIC LIQUID ON STABILIZER DIELECTRIC CAPACITIVITY AND DISPERSION MEDIUM ». IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENIY KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 60, n^o 4 (12 mai 2017) : 75. http://dx.doi.org/10.6060/tcct.2017604.5506.

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The purpose of this article is to research the possibility of using values of stabilizer dielectric capacitivity and dispersion medium to form a colloidal stability criterion of magnetic liquid. The authors researched colloidal stability of magnetic liquids with a low-polarity base, nonionogenous SAM-stabilizer (oligoester) and hydroximag nanoparticles. The received magnetic colloids were tested for stability in a gravity field to evaluate SAM stabilizing capacity. The authors propose Е-criterion that shows a relative difference between dielectric capacitivities of a dispersion medium and SAM-stabilizer. It was determined that such combination of dielectric capacitivity of solution component parts correlates with the values of SAM adsorption and colloid stability in the best way. The test results show that relative reduction of magnetization correlates well with a value of dispersion medium dielectric capacitivity due to irreversible sedimentative processes. In the next set of experiments, the authors did not change the magnetic colloid liquid content, but SAM-stabilizer. They research the dependence of colloidal stability of magnetic liquids based on a dioctyl sebacate of a stabilized SAM with various dielectric capacitivities. The test results prove regularity of increasing colloidal stability with decreasing E- criterion. The paper considers in details the physical and chemical mechanisms that help to develop the influence of dielectric capacitivity on magnetic liquid colloidal stability. The analysis of testing results showed that dielectric capacitivity of magnetic liquid components affects many physical-chemical phenomenons in the process of its synthesis. It is important that the behaviour of sorption processes on the surface of dispersed particles depends on dielectric capacitivity. The result of the empirical data research by magnetic liquid colloidal stability shows that with increasing dielectric capacitivity of dispersion medium in relation to stabilizer’s dielectric capacitivity the desorption processes of stabilizer’s molecules from a magnetic particles’ surface increses. As a result, the adsorption layer around particles becomes more incoherent and less competent. It reduces the value of a steric stabilization factor of a magnetic liquid colloidal structure. In practice it leads to deterioration or even loss of colloidal stability of magnetic liquid. The influence of dielectric capacitivity on colloidal stability using the effects of interparticle interaction is less important. To summarize, the article proves a dielectric E-criterion that can be used to provide rationale for the choice of SAM-stabilizer for magnetic liquids. According to this criterion, dielectric capacitivity of a dispersion medium should be slightly different from the similar property of SAM-stabilizer. Otherwise, molecule desorption processes of SAM from magnetic particles encourage quality degradation of covering adsorption layers, so colloidal stability worsens.Forcitation:Bolotov A.N., Novikov V.V., Novikova O.O. On dependence of colloidal stability of magnetic liquid on stabilizer dielectric capacitivity and dispersion medium. Izv. Vyssh. Uchebn. Zaved. Khim. Khim. Tekhnol. 2017. V. 60. N 4. P. 75-81.

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Erdem, Talha, et Hilmi Volkan Demir. « Colloidal nanocrystals for quality lighting and displays : milestones and recent developments ». Nanophotonics 5, n^o 1 (1 juin 2016) : 74–95. http://dx.doi.org/10.1515/nanoph-2016-0009.

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AbstractRecent advances in colloidal synthesis of nanocrystals have enabled high-quality high-efficiency light-emitting diodes, displays with significantly broader color gamut, and optically-pumped lasers spanning the whole visible regime. Here we review these colloidal platforms covering the milestone studies together with recent developments. In the review, we focus on the devices made of colloidal quantum dots (nanocrystals), colloidal quantum rods (nanorods), and colloidal quantum wells (nanoplatelets) as well as those of solution processed perovskites and phosphor nanocrystals. The review starts with an introduction to colloidal nanocrystal photonics emphasizing the importance of colloidal materials for light-emitting devices. Subsequently,we continue with the summary of important reports on light-emitting diodes, in which colloids are used as the color converters and then as the emissive layers in electroluminescent devices. Also,we review the developments in color enrichment and electroluminescent displays. Next, we present a summary of important reports on the lasing of colloidal semiconductors. Finally, we summarize and conclude the review presenting a future outlook.

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Forcada, Jacqueline, et Roque Hidalgo-Alvarez. « Functionalized Polymer Colloids : Synthesis and Colloidal Stability ». Current Organic Chemistry 9, n^o 11 (1 juillet 2005) : 1067–84. http://dx.doi.org/10.2174/1385272054368484.

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ALAM, FAHAD, SAJID ALI ANSARI, WASI KHAN, M. EHTISHAM KHAN et A. H. NAQVI. « SYNTHESIS, STRUCTURAL, OPTICAL AND ELECTRICAL PROPERTIES OF IN-SITU SYNTHESIZED POLYANILINE/SILVER NANOCOMPOSITES ». Functional Materials Letters 05, n^o 03 (septembre 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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Riess, Jean G., et Marie Pierre Krafft. « Fluorocarbons and Fluorosurfactants for In Vivo Oxygen Transport (Blood Substitutes), Imaging, and Drug Delivery ». MRS Bulletin 24, n^o 5 (mai 1999) : 42–48. http://dx.doi.org/10.1557/s0883769400052313.

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The development of biomaterials to treat, repair, or reconstruct the human body is an increasingly important component of materials research. Collaboration between materials researchers and their industrial and clinical partners is essential for the development of this complex field. To demonstrate the importance of these interactions, two articles in this issue focus on advances in biomaterials relating to the use of colloidal systems for transport, drug delivery, and other medical applications. These articles were coordinated by Dominique Muster (Université Louis Pasteur, Strasbourg) and Franz Burny (Hôpital Erasme, Brussels). The following is the first of these two articles.A large variety of colloidal Systems involving highly fluorinated components have been prepared and investigated in recent years. These fluorinated Systems comprise diverse ty pes of emulsions (e.g., direct, reverse, and multiple emulsions; microemulsions; gel emulsions; waterless emulsions) with a fluorocarbon phase (and often a fluorinated Surfactant), and a ränge of self-assemblies (vesicles, tubules, helices, ribbons, etc.) made from fluorinated amphiphiles. Fluorinated Langmuir films and fluorinated black lipid membranes (BLMs) also have been investigated.Research in this area was driven by the potential applications of such materials in medicine and biology. Fluorocarbon-based products are being developed as injectable oxygen carriers (“blood Substitutes”), media for liquid Ventilation, drug delivery Systems, and contrast agents for ultrasound imaging. One such agent has recently been approved for use in Europe and the United States. Several more products are in an advanced stage of clinical evaluation, and others are in various stages of preclinical development. From a more fundamental Standpoint, these materials are being investigated for assessing and understanding the impact that fluorinated components have on the formation, stability, structure, and properties of colloida l Systems in comparison with their hydrocarbon counterparts. The attention given to fluorinated colloids prompted the synthesis of numerous new families of fluorinated amphiphiles, which were to become components of such colloids.

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Smith, Gregory N., Matthew J. Derry, James E. Hallett, Joseph R. Lovett, Oleksander O. Mykhaylyk, Thomas J. Neal, Sylvain Prévost et Steven P. Armes. « Refractive index matched, nearly hard polymer colloids ». Proceedings of the Royal Society A : Mathematical, Physical and Engineering Sciences 475, n^o 2226 (juin 2019) : 20180763. http://dx.doi.org/10.1098/rspa.2018.0763.

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Refractive index matched particles serve as essential model systems for colloid scientists, providing nearly hard spheres to explore structure and dynamics. The poly(methyl methacrylate) latexes typically used are often refractive index matched by dispersing them in binary solvent mixtures, but this can lead to undesirable changes, such as particle charging or swelling. To avoid these shortcomings, we have synthesized refractive index matched colloids using polymerization-induced self-assembly (PISA) rather than as polymer latexes. The crucial difference is that these diblock copolymer nanoparticles consist of a single core-forming polymer in a single non-ionizable solvent. The diblock copolymer chosen was poly(stearyl methacrylate)–poly(2,2,2-trifluoroethyl methacrylate) (PSMA–PTFEMA), which self-assembles to form PTFEMA core spheres in n -alkanes. By monitoring scattered light intensity, n -tetradecane was found to be the optimal solvent for matching the refractive index of such nanoparticles. As expected for PISA syntheses, the diameter of the colloids can be controlled by varying the PTFEMA degree of polymerization. Concentrated dispersions were prepared, and the diffusion of the PSMA–PTFEMA nanoparticles as a function of volume fraction was measured. These diblock copolymer nanoparticles are a promising new system of transparent spheres for future colloidal studies.

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Болотов, Александр Николаевич, Ольга Олеговна Новикова et Владимир Валентинович Мешков. « VISCOMETRIC STUDIES IN THE PROCESS OF SYNTHESIS OF MAGNETIC LUBRICANT NANO-OILS ». Physical and Chemical Aspects of the Study of Clusters, Nanostructures and Nanomaterials, n^o 14 (15 décembre 2022) : 531–44. http://dx.doi.org/10.26456/pcascnn/2022.14.531.

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В области трибологии перспективны магнитные смазочные масла, в которых для повышения их коллоидной устойчивости используют полимеры, однако их применение ограничено низкой намагниченностью коллоида. Повысить намагниченность наномасел возможно путем синтеза полимерных оболочек непосредственно на поверхности магнитных частиц в процессе получения наномасел. Описаны особенности технологии синтеза магнитных смазочных наномасел с полимерными сольватными оболочками на частицах, которые защищают их от коагуляции. Полимеризация молекул гидроксикислоты протекает по механизму поликонденсации на твердой поверхности магнетита. Вязкость магнитного коллоида возрастает из-за увеличения толщины сольватной оболочки. Исходя из этого предложено дифференциальное уравнение, которое показывает зависимость скорости роста вязкости коллоида от скорости реакции поликонденсации. Экспериментальная проверка уравнения показала, что оно выполняется с точностью до 8%. Полученное уравнение позволяет определить важную термодинамическую характеристику -энергии активации процесса синтеза полимерных оболочек на поверхности дисперсных частиц. Для расчетов нужно знать скорость изменения вязкости коллоида с дисперсионной средой без мономера (гидрокислоты). Поэтому, в процессе синтеза полимера отбираются пробы промежуточного магнитного коллоида небольшого объема, которые используются для определения вязкости коллоида и дисперсионной среды, содержащей мономер. Затем находится вязкость коллоида с чистой дисперсионной средой, необходимая для расчетов энергии активации реакции поликонденсации. По оценочным расчетам, ошибка определения энергии активации не превышает 11%. На практике, с помощью установленного значения энергии активации полимеризации, можно выполнять целенаправленный выбор оптимального температурно-временного режима стабилизации магнитного коллоида с целью получения магнитного наномасла с требуемыми характеристиками вязкости и агрегативной устойчивости. Экспериментальные исследования проводились на специально разработанных приборах для оценки коллоидной стабильности и динамической вязкости магнитных коллоидов. In the field of tribology, magnetic lubricating oils are promising, in which polymers are used to increase their colloidal stability, but their use is limited by the low magnetization of the colloid. It is possible to increase the magnetization of nanooils by synthesizing polymer shells directly on the surface of magnetic particles in the process of obtaining nanooils. The features of the technology for the synthesis of magnetic lubricating nanooils with polymeric solvation shells on particles, which protect them from coagulation, are described. Polymerization of hydroxy acid molecules proceeds by the mechanism of polycondensation on the solid surface of magnetite. The viscosity of the magnetic colloid increases due to the increase in the thickness of the solvate shell. Proceeding from this, a differential equation is proposed, which shows the dependence of the growth rate of the colloid viscosity on the rate of the polycondensation reaction. An experimental verification of the equation showed that it is fulfilled with an accuracy up to 8%. The resulting equation makes it possible to determine an important thermodynamic characteristic - the activation energy of the process of synthesis of polymer shells on the surface of dispersed particles. For calculations, it is necessary to know the rate of change in the viscosity of a colloid with a dispersion medium without a monomer (hydroacid). Therefore, in the process of the polymer synthesis, samples of the intermediate magnetic colloid of a small volume are taken, which are used to determine the viscosity of the colloid and dispersion medium containing monomers. Then the viscosity of the colloid with a pure dispersion medium is found, which is necessary for calculating the activation energy of the polycondensation reaction. According to estimates, the error in determining the activation energy does not exceed 11%. In practice, using the values of the activation energy of polymerization, it is possible to carry out a purposeful choice of the optimal temperature-time regime for stabilizing the magnetic colloid in order to obtain a magnetic nanooil with the required viscosity and aggregative stability characteristics. Experimental studies were carried out on specially designed instruments for assessing the colloidal stability and dynamic viscosity of magnetic colloids.

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Palangetic, Ljiljana, Kirill Feldman, Raphael Schaller, Romana Kalt, Walter R. Caseri et Jan Vermant. « From near hard spheres to colloidal surfboards ». Faraday Discussions 191 (2016) : 325–49. http://dx.doi.org/10.1039/c6fd00052e.

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This work revisits the synthesis of the colloidal particles most commonly used for making model near hard suspensions or as building blocks of model colloidal gels, i.e. sterically stabilised poly(methyl methacrylate) (PMMA) particles. The synthesis of these particles is notoriously hard to control and generally the problems are ascribed to the difficulty in synthesising the graft stabiliser (PMMA-g-PHSA). In the present work, it is shown that for improving the reliability of the synthesis as a whole, control over the polycondensation of the 12-polyhydroxystearic acid is the key. By changing the catalyst and performing the polycondensation in the melt, the chain length of the 12-polyhydroxystearic acid is better controlled, as confirmed by ¹H-NMR spectroscopy. Control over the graft copolymer now enables us to make small variations of near hard sphere colloids, for example spherical PMMA particles with essentially the same core size and different stabilising layer thicknesses can now be readily produced, imparting controlled particle softness. The PMMA spheres can be further employed to create, in gram scale quantities, colloidal building blocks having geometrical and/or chemical anisotropy by using a range of mechanical deformation methods. The versatility of the latter methods is demonstrated for polystyrene latex particles as well.

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Quinson, Jonathan, Søren Bredmose Simonsen, Luise Theil Kuhn et Matthias Arenz. « Commercial Spirits for Surfactant-Free Syntheses of Electro-Active Platinum Nanoparticles ». Sustainable Chemistry 2, n^o 1 (4 janvier 2021) : 1–7. http://dx.doi.org/10.3390/suschem2010001.

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The Co4CatTM process is a simple, surfactant-free method to produce colloidal dispersions of precious metal nanoparticles in alkaline mono-alcohols. The synthesis is performed in low-boiling-point solvents and is relevant for industrial production. The robustness of the process is demonstrated by using three different commercial spirits as solvents to obtain Pt nanoparticles. The results demonstrate that careful control of the solvent purity is not needed to achieve the synthesis of stable 2 nm platinum nanoparticle colloids readily active electrocatalysts for energy conversion reactions like the methanol oxidation.

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Saikia, Jyoti Prasad, Bably Khatun, Bhaskarjyoti Gogoi, Alak Kumar Buragohain et Yutika Nath. « Vigna mungo Seed Non-Destructive Based Colloidal Silver Nanoparticle Synthesis and Toxicity ». Indian Journal of Biology 3, n^o 2 (2016) : 119–26. http://dx.doi.org/10.21088/ijb.2394.1391.3216.5.

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Fediv, V. I. « Synthesis of colloidal nanoparticles CdS:Mn in the polymer solution for biological applications ». Functional Materials 21, n^o 2 (30 juin 2014) : 220–25. http://dx.doi.org/10.15407/fm21.02.220.

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Yang, Ren Chun, Feng Yun Ma et Ding Xing Tang. « Template Synthesis to Fabrication of 3D Ordered Hierarchical Materials ». Advanced Materials Research 602-604 (décembre 2012) : 1355–58. http://dx.doi.org/10.4028/www.scientific.net/amr.602-604.1355.

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To construct 3D ordered hierarchical materials, Si, Al and Ti colloids precursors were controlled prepared via dual template method in which the colloidal crystals and P123 acted as hard-template and soft-template, respectively. The results showed that ordered hierarchical SiO2, Al2O3 and TiO2 were successfully prepared. The difference of the structure of samples suggested that hydrolysis rate of the precursors play an important role on pore structure of the samples.

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Saadah, Fatkhiyatus, Rizka Zakiyatul Miskiyah et Ali Khumaeni. « Zinc Oxide Nanoparticles (ZnONPs) Photocatalyst using Pulse Laser Ablation Method for Antibacterial in Water Polluted ». Journal of Physics and Its Applications 2, n^o 2 (6 juin 2020) : 102–6. http://dx.doi.org/10.14710/jpa.v2i2.8001.

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Synthesis of zinc oxide nanoparticles by pulse laser ablation method has been successed carried out. Synthesis was carried out in aquades medium with a repetition rate variation of 5 Hz, 10 Hz and 15 Hz pulse laser yielding brown colloids. The higher laser repetition rate, the colloidal color will be more dark brown. Characterization of zinc oxide nanoparticles includes UV-Vis, SEM-EDX, FTIR and XRD. The image of SEM shows that zinc oxide nanoparticles have a round shape. Measurement of particle distribution with imageJ software from SEM images showed that ZnO nanoparticles were 23.63 nm, 12.13 nm and 5.59 nm for 5 Hz, 10 Hz and 15 Hz shots. The EDX spectrum analysis results show that only Zn and O atoms in the ZnO nanoparticles colloid are synthesized. FTIR results showed that sprocket ZnO was formed at wave number 457 cm-1 and 545 cm-1. The XRD analysis results also show some peaks known as the ZnO phase. This indicates that ZnO nanoparticles have been formed. The testing of the antibacterial activity of ZnO nanoparticles using a liquid dilution method with nanoparticle concentrations of 40 ppm, 60 ppm and 80 ppm. The test results showed the percentage of degradation of Escherichia coli bacteria at concentrations of 40 ppm, 60 ppm and 80 ppm respectively at 89.60%, 97.76% and 98, 70%.

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Байдакова, М. В., Н. А. Германов, С. Н. Голяндин, М. Е. Компан, С. В. Мочалов, А. В. Нащекин, В. Н. Неведомский et al. « Слабоупорядоченный наноструктурированный бисиликат серебра и его коллоидные растворы : получение и свойства ». Журнал технической физики 89, n^o 6 (2019) : 938. http://dx.doi.org/10.21883/jtf.2019.06.47644.372-18.

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AbstractIt was shown that the interaction of silver cations in alkaline aqueous solutions with various kinds of silicates, regardless of their chemical and aggregation state, leads to the formation of an exclusively disilicate form of silver salt. We develop procedures for synthesis of nanostructured weakly ordered nonstoichiometric silver disilicate Ag_6 –_ x H_ x Si_2O_7 capable of forming aqueous colloids. We study the micellular structure of colloidal particles in these solutions and demonstrate that permeability of silicic acid layers enveloping nanosized salt cores of these micelles depends on pH. Colloidal silver disilicate is found to exhibit a high catalytic activity in photoinduced oxidation of a broad spectrum of different compounds, which is demonstrated for compounds stable in aqueous solutions such as some organic dies and ferrocyanide complex ([Fe(CN $$)_{6}^{{ - 4}}$$ ).

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Nayak, Rekha, Jane Galsworthy, Peter Dobson et John Hutchison. « Synthesis of gold-cadmium selenide co-colloids ». Journal of Materials Research 13, n^o 4 (avril 1998) : 905–8. http://dx.doi.org/10.1557/jmr.1998.0123.

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Semiconductor-metal co-colloids of CdSey/Au have been prepared by various synthetic pathways. Their microstructure, including that of Au–CdSe(TOPO) co-colloid in a core-shell structure, has been examined by high resolution transmission electron microscopy (HRTEM) and found to be well defined within the 10 nm size range. The optical absorption spectra of the colloids and of various synthesis stages have been obtained.

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Cheng, Tong, Fang, Wang, Liu et Tan. « Ammonium-Induced Synthesis of Highly Fluorescent Hydroxyapatite Nanoparticles with Excellent Aqueous Colloidal Stability for Secure Information Storage ». Coatings 9, n^o 5 (27 avril 2019) : 289. http://dx.doi.org/10.3390/coatings9050289.

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In this paper, uniform hydroxyapatite (HA) nanoparticles, with excellent aqueous colloidal stability and high fluorescence, have been successfully synthesized via a citrate-assisted hydrothermal method. The effect of the molar ratio of ammonium phosphate in phosphate (RAMP) and hydrothermal time on the resultant products was characterized in terms of crystalline structure, morphology, colloidal stability, and fluorescence behavior. When the RAMP is 50% and the hydrothermal time is 4 h, the product consists of a pure hexagonal HA phase and a uniform rod-like morphology, with 120- to 150-nm length and approximately 20-nm diameter. The corresponding dispersion is colloidally stable, and transparent for at least one week, and has an intense bright blue emission (centered at 440 nm, 11.6-ns lifetime, and 73.80% quantum efficiency) when excited by 340-nm UV light. Although prolonging the hydrothermal time and increasing the RAMP had no appreciable effect on the aqueous colloidal stability of HA nanoparticles, the fluorescence intensity was enhanced. The cause of HA fluorescence are more biased towards carbon dots (which are mainly polymer clusters and/or molecular fluorophores constituents) trapped in the hydroxyapatite crystal structure. Owing to these properties, a highly fluorescent HA colloidal dispersion could find applications in secure information storage.

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Soleimani Zohr Shiri, Mohammad, William Henderson et Michael R. Mucalo. « A Review of The Lesser-Studied Microemulsion-Based Synthesis Methodologies Used for Preparing Nanoparticle Systems of The Noble Metals, Os, Re, Ir and Rh ». Materials 12, n^o 12 (12 juin 2019) : 1896. http://dx.doi.org/10.3390/ma12121896.

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This review focuses on the recent advances in the lesser-studied microemulsion synthesis methodologies of the following noble metal colloid systems (i.e., Os, Re, Ir, and Rh) using either a normal or reverse micelle templating system. The aim is to demonstrate the utility and potential of using this microemulsion-based approach to synthesize these noble metal nanoparticle systems. Firstly, some fundamentals and important factors of the microemulsion synthesis methodology are introduced. Afterward, a review of the investigations on the microemulsion syntheses of Os, Re, Ir, and Rh nanoparticle (NP) systems (in all forms, viz., metallic, oxide, mixed-metal, and discrete molecular complexes) is presented for work published in the last ten years. The chosen noble metals are traditionally very reactive in nanosized dimensions and have a strong tendency to aggregate when prepared via other methods. Also, the particle size and particle size distribution of these colloids can have a significant impact on their catalytic performance. It is shown that the microemulsion approach has the capability to better stabilize these metal colloids and can control the size of the synthesized NPs. This generally leads to smaller particles and higher catalytic activity when they are tested in applications.

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Zhang, Dongshi, Wonsuk Choi, Jurij Jakobi, Mark-Robert Kalus, Stephan Barcikowski, Sung-Hak Cho et Koji Sugioka. « Spontaneous Shape Alteration and Size Separation of Surfactant-Free Silver Particles Synthesized by Laser Ablation in Acetone during Long-Period Storage ». Nanomaterials 8, n^o 7 (13 juillet 2018) : 529. http://dx.doi.org/10.3390/nano8070529.

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The technique of laser ablation in liquids (LAL) has already demonstrated its flexibility and capability for the synthesis of a large variety of surfactant-free nanomaterials with a high purity. However, high purity can cause trouble for nanomaterial synthesis, because active high-purity particles can spontaneously grow into different nanocrystals, which makes it difficult to accurately tailor the size and shape of the synthesized nanomaterials. Therefore, a series of questions arise with regards to whether particle growth occurs during colloid storage, how large the particle size increases to, and into which shape the particles evolve. To obtain answers to these questions, here, Ag particles that are synthesized by femtosecond (fs) laser ablation of Ag in acetone are used as precursors to witness the spontaneous growth behavior of the LAL-generated surfactant-free Ag dots (2–10 nm) into different polygonal particles (5–50 nm), and the spontaneous size separation phenomenon by the carbon-encapsulation induced precipitation of large particles, after six months of colloid storage. The colloids obtained by LAL at a higher power (600 mW) possess a greater ability and higher efficiency to yield colloids with sizes of <40 nm than the colloids obtained at lower power (300 mW), because of the generation of a larger amount of carbon ‘captors’ by the decomposition of acetone and the stronger particle fragmentation. Both the size increase and the shape alteration lead to a redshift of the surface plasmon resonance (SPR) band of the Ag colloid from 404 nm to 414 nm, after storage. The Fourier transform infrared spectroscopy (FTIR) analysis shows that the Ag particles are conjugated with COO– and OH– groups, both of which may lead to the growth of polygonal particles. The CO and CO2 molecules are adsorbed on the particle surfaces to form Ag(CO)x and Ag(CO2)x complexes. Complementary nanosecond LAL experiments confirmed that the particle growth was inherent to LAL in acetone, and independent of pulse duration, although some differences in the final particle sizes were observed. The nanosecond-LAL yields monomodal colloids, whereas the size-separated, initially bimodal colloids from the fs-LAL provide a higher fraction of very small particles that are <5 nm. The spontaneous growth of the LAL-generated metallic particles presented in this work should arouse the special attention of academia, especially regarding the detailed discussion on how long the colloids can be preserved for particle characterization and applications, without causing a mismatch between the colloid properties and their performance. The spontaneous size separation phenomenon may help researchers to realize a more reproducible synthesis for small metallic colloids, without concern for the generation of large particles.

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Hupfeld, Tim, Frederic Stein, Stephan Barcikowski, Bilal Gökce et Ulf Wiedwald. « Manipulation of the Size and Phase Composition of Yttrium Iron Garnet Nanoparticles by Pulsed Laser Post-Processing in Liquid ». Molecules 25, n^o 8 (17 avril 2020) : 1869. http://dx.doi.org/10.3390/molecules25081869.

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Modification of the size and phase composition of magnetic oxide nanomaterials dispersed in liquids by laser synthesis and processing of colloids has high implications for applications in biomedicine, catalysis and for nanoparticle-polymer composites. Controlling these properties for ternary oxides, however, is challenging with typical additives like salts and ligands and can lead to unwanted byproducts and various phases. In our study, we demonstrate how additive-free pulsed laser post-processing (LPP) of colloidal yttrium iron oxide nanoparticles using high repetition rates and power at 355 nm laser wavelength can be used for phase transformation and phase purification of the garnet structure by variation of the laser fluence as well as the applied energy dose. Furthermore, LPP allows particle size modification between 5 nm (ps laser) and 20 nm (ns laser) and significant increase of the monodispersity. Resulting colloidal nanoparticles are investigated regarding their size, structure and temperature-dependent magnetic properties.

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Antipov, A. A., A. G. Putilov, A. V. Osipov, A. E. Shepelev, V. N. Glebov et A. M. Maliutin. « Synthesis of copper nanoparticles by laser ablation ». Journal of Physics : Conference Series 2316, n^o 1 (1 août 2022) : 012004. http://dx.doi.org/10.1088/1742-6596/2316/1/012004.

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Abstract The synthesis of copper nanoparticles using a pulsed alexandrite laser is demonstrated. The laser operated in a free generation mode with a pulse duration of about 250 μs. The copper target was placed in distilled water and glycerin. The obtained colloidal solutions were investigated by dynamic light scattering, and the deposited structures were studied by atomic force and electron microscopy. The concentration of nanoparticles depended on the power of the laser radiation, the scanning speed and the exposure time. The smallest particles size was obtained at a frequency of 5 Hz at a wavelength of 750 nm. Colloids obtained in distilled water contain copper nanoparticles, which oxidize over time.

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Cárdenas-Triviño, Galo, et Sergio Triviño-Matus. « Synthesis and characterization of Fe, Co, and Ni colloids in 2-mercaptoethanol ». Nanomaterials and Nanotechnology 10 (1 janvier 2020) : 184798042096688. http://dx.doi.org/10.1177/1847980420966883.

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Metal colloids in 2-mercaptoethanol using nanoparticles (NPs) of iron (Fe), cobalt (Co), and nickel (Ni) were prepared by chemical liquid deposition method. Transmission electron microscopy, electron diffraction, UV-VIS spectroscopy, and scanning electron microscopy with electron dispersive X-ray spectroscopy characterized the resulting colloidal dispersions. The NPs exhibited sizes with ranges from 9.8 nm for Fe, 3.7 nm for Co, and 7.2 nm for Ni. The electron diffraction shows the presence of the metals in its elemental state Fe (0), Co (0), and Ni (0) and also some compounds FeO (OH), CoCo2S4, and NiNi2S4.

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Basina, Georgia, Hafsa Khurshid, Nikolaos Tzitzios, George Hadjipanayis et Vasileios Tzitzios. « Facile Organometallic Synthesis of Fe-Based Nanomaterials by Hot Injection Reaction ». Nanomaterials 11, n^o 5 (28 avril 2021) : 1141. http://dx.doi.org/10.3390/nano11051141.

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Fe-based colloids with a core/shell structure consisting of metallic iron and iron oxide were synthesized by a facile hot injection reaction of iron pentacarbonyl in a multi-surfactant mixture. The size of the colloidal particles was affected by the reaction temperature and the results demonstrated that their stability against complete oxidation related to their size. The crystal structure and the morphology were identified by powder X-ray diffraction and transmission electron microscopy, while the magnetic properties were studied at room temperature with a vibrating sample magnetometer. The injection temperature plays a very crucial role and higher temperatures enhance the stability and the resistance against oxidation. For the case of injection at 315 °C, the nanoparticles had around a 10 nm mean diameter and revealed 132 emu/g. Remarkably, a stable dispersion was created due to the colloids’ surface functionalization in a nonpolar solvent.

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Popova-Kuznetsova, Elena, Gleb Tikhonowski, Anton A. Popov, Vladimir Duflot, Sergey Deyev, Sergey Klimentov, Irina Zavestovskaya, Paras N. Prasad et Andrei V. Kabashin. « Laser-Ablative Synthesis of Isotope-Enriched Samarium Oxide Nanoparticles for Nuclear Nanomedicine ». Nanomaterials 10, n^o 1 (28 décembre 2019) : 69. http://dx.doi.org/10.3390/nano10010069.

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Nuclear nanomedicine is an emerging field, which utilizes nanoformulations of nuclear agents to increase their local concentration at targeted sites for a more effective nuclear therapy at a considerably reduced radiation dosage. This field needs the development of methods for controlled fabrication of nuclear agents carrying nanoparticles with low polydispersity and with high colloidal stability in aqueous dispersions. In this paper, we apply methods of femtosecond (fs) laser ablation in deionized water to fabricate stable aqueous dispersion of 152Sm-enriched samarium oxide nanoparticles (NPs), which can capture neutrons to become 153Sm beta-emitters for nuclear therapy. We show that direct ablation of a 152Sm-enriched samarium oxide target leads to widely size- and shape-dispersed populations of NPs with low colloidal stability. However, by applying a second fs laser fragmentation step to the dispersion of initially formed colloids, we achieve full homogenization of NPs size characteristics, while keeping the same composition. We also demonstrate the possibility for wide-range tuning of the mean size of Sm-based NPs by varying laser energy during the ablation or fragmentation step. The final product presents dispersed solutions of samarium oxide NPs with relatively narrow size distribution, having spherical shape, a controlled mean size between 7 and 70 nm and high colloidal stability. The formed NPs can also be of importance for catalytic and biomedical applications.

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Wawrzyniak, Jakub, Jakub Karczewski, Jacek Ryl, Katarzyna Grochowska et Katarzyna Siuzdak. « Laser-Assisted Synthesis and Oxygen Generation of Nickel Nanoparticles ». Materials 13, n^o 18 (13 septembre 2020) : 4068. http://dx.doi.org/10.3390/ma13184068.

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Nowadays, more than ever, environmental awareness is being taken into account when it comes to the design of novel materials. Herein, the pathway to the creation of a colloid of spherical, almost purely metallic nickel nanoparticles (NPs) through pulsed laser ablation in ethanol is presented. A complex description of the colloid is provided through UV-vis spectroscopy and dynamic light scattering analysis, ensuring insight into laser-induced nanoparticle homogenization and size-control of the NPs. The transmission electron spectroscopy revealed spherical nanoparticles with a narrow size distribution, whereas the energy-dispersive X-ray spectroscopy accompanied by the X-ray photoelectron spectroscopy revealed their metallic nature. Furthermore, an example of the application of the colloidal nanoparticles is presented, where a quick, five-min ultrasound modification results in over an order of magnitude higher current densities in the titania-based electrode for the oxygen evolution reaction.

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Małaczewska, J. « The in vitro effect of commercially available noble metal nanocolloids on the splenocyte proliferative response and cytokine production in mice ». Polish Journal of Veterinary Sciences 17, n^o 1 (1 mars 2014) : 37–45. http://dx.doi.org/10.2478/pjvs-2014-0005.

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Abstract Noble metal nanoparticles, currently among the most popular types of nanomaterials, are capable of penetrating through biological barriers once they enter a living organism. There, they can permeate into organs possessing the reticuloendothelial system, such as the spleen. The objective of this study was to determine the effect of commercial nanocolloids of noble metals (silver, gold and copper), recommended by the manufacturer as dietary supplements, on the in vitro viability, proliferative activity and production of cytokines (IL-1β, IL-2, IL-6, IL- 10 and TNF-α) by mouse splenocytes. All of the analyzed colloids had some effect on the activity of mouse splenocytes. Silver colloid was characterized by high toxicity - concentrations of 1.25 ppm and above substantially depressed the viability of cells as well as their proliferative activity and ability to synthesize cytokines. The other two colloids were far less toxic than nanosilver, although their non-toxic concentrations had a significant effect on the production of cytokines by mitogen activated splenocytes. The colloid of gold decreased the level of IL-2, and the colloid of copper caused an increase in IL-2, IL6 and Il-10. At the same time, copper colloid alone induced the synthesis of IL-1β in mitogen unstimulated cells. The results indicate that colloids of noble metals are capable of affecting the activity of immunocompetent cells in important peripheral organs of the immune system.

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Varvarenko, Sergiy, Ihor Tarnavchyk, Andriy Voronov, Nataliia Fihurka, Iryna Dron, Nataliia Nosova, Roman Taras, Volodymyr Samaryk et Stanislav Voronov. « Synthesis and Colloidal Properties of Polyesters Based on Glutamic Acids and Glycols of Different Nature ». Chemistry & ; Chemical Technology 7, n^o 2 (10 juin 2013) : 161–68. http://dx.doi.org/10.23939/chcht07.02.161.

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Siebeneicher, Simon, Friedrich Waag, Marianela Escobar Castillo, Vladimir V. Shvartsman, Doru C. Lupascu et Bilal Gökce. « Laser Fragmentation Synthesis of Colloidal Bismuth Ferrite Particles ». Nanomaterials 10, n^o 2 (19 février 2020) : 359. http://dx.doi.org/10.3390/nano10020359.

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Laser fragmentation of colloidal submicron-sized bismuth ferrite particles was performed by irradiating a liquid jet to synthesize bismuth ferrite nanoparticles. This treatment achieved a size reduction from 450 nm to below 10 nm. A circular and an elliptical fluid jet were compared to control the energy distribution within the fluid jet and thereby the product size distribution and educt decomposition. The resulting colloids were analysed via UV-VIS, XRD and TEM. All methods were used to gain information on size distribution, material morphology and composition. It was found that using an elliptical liquid jet during the laser fragmentation leads to a slightly smaller and narrower size distribution of the resulting product compared to the circular jet.

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Mann, Daniel, Stefanie Voogt, Ryan van Zandvoort, Helmut Keul, Martin Möller, Marcel Verheijen, Daniel Nascimento-Duplat et al. « Protecting patches in colloidal synthesis of Au semishells ». Chemical Communications 53, n^o 27 (2017) : 3898–901. http://dx.doi.org/10.1039/c7cc00689f.

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Li, Qiao, Xiaosong Zheng, Xiaoyu Shen, Shuai Ding, Hongjian Feng, Guohua Wu et Yaohong Zhang. « Optimizing the Synthetic Conditions of “Green” Colloidal AgBiS2 Nanocrystals Using a Low-Cost Sulfur Source ». Nanomaterials 12, n^o 21 (25 octobre 2022) : 3742. http://dx.doi.org/10.3390/nano12213742.

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Colloidal AgBiS2 nanocrystals (NCs) have attracted increasing attention as a near–infrared absorbent materials with non–toxic elements and a high absorption coefficient. In recent years, colloidal AgBiS2 NCs have typically been synthesized via the hot injection method using hexamethyldisilathiane (TMS) as the sulfur source. However, the cost of TMS is one of the biggest obstacles to large–scale synthesis of colloidal AgBiS2 NCs. Herein, we synthesized colloidal AgBiS2 NCs using oleylamine@sulfur (OLA–S) solution as the sulfur source instead of TMS and optimized the synthesis conditions of colloidal AgBiS2 NCs. By controlling the reaction injection temperature and the dosage of OLA–S, colloidal AgBiS2 NCs with adjustable size can be synthesized. Compared with TMS–based colloidal AgBiS2 NCs, the colloidal AgBiS2 NCs based on OLA–S has good crystallinity and fewer defects.

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Yu, Bing, Hai-Lin Cong, Li-Xin Zhang, Shu-Jing Yang, Jian-Guo Tang et Xiu-Song Zhao. « Synthesis of P(St-MMA-AA) Colloids and Application in Colloidal Crystals ». Integrated Ferroelectrics 128, n^o 1 (janvier 2011) : 44–48. http://dx.doi.org/10.1080/10584587.2011.576180.

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Chattopadhyay, D. P., et B. H. Patel. « Effect of Nanosized Colloidal Copper on Cotton Fabric ». Journal of Engineered Fibers and Fabrics 5, n^o 3 (septembre 2010) : 155892501000500. http://dx.doi.org/10.1177/155892501000500301.

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This research deals with the synthesis of nanosized copper as colloidal solution and its application to cotton fabric. Copper nano colloids were prepared by chemical reduction of copper salt using sodium borohydride as reducing agent in presence of tri-sodium citrate. The size and size distribution of the particles were examined by particle size analyzer and the morphology of the synthesized particles was examined by SEM and AFM techniques. X-ray fluorescence spectroscopy detected the presence of copper in the treated fabric. The results of particle size analysis showed that the average particle size varied from 60 nm to 100 nm. The nano copper treated cotton was subjected to soil burial test for the assessment of its resistance towards microbial attack. SEM images of treated fabric indicate copper nano particles are well dispersed on the surface of the specimens. The treatments of nano copper colloidal solution on cotton not only improve its antimicrobial efficiency but also influenced the tensile strength of the fabric sample positively. The treatment was found to enhance the color depth and fastness properties of direct dyed cotton fabric samples.

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Sandu, Ion, Claudiu Teodor Fleaca, Florian Dumitrache, Bogdan Alexandru Sava, Iuliana Urzica, Iulia Antohe, Simona Brajnicov et Marius Dumitru. « Shaping in the Third Direction ; Synthesis of Patterned Colloidal Crystals by Polyester Fabric-Guided Self-Assembly ». Polymers 13, n^o 23 (24 novembre 2021) : 4081. http://dx.doi.org/10.3390/polym13234081.

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A polyester fabric with rectangular openings was used as a sacrificial template for the guiding of a sub-micron sphere (polystyrene (PS) and silica) aqueous colloid self-assembly process during evaporation as a patterned colloidal crystal (PCC). This simple process is also a robust one, being less sensitive to external parameters (ambient pressure, temperature, humidity, vibrations). The most interesting feature of the concave-shape-pattern unit cell (350 μm × 400 μm × 3 μm) of this crystal is the presence of triangular prisms at its border, each prism having a one-dimensional sphere array at its top edge. The high-quality ordered single layer found inside of each unit cell presents the super-prism effect and left-handed behavior. Wider yet elongated deposits with ordered walls and disordered top surfaces were formed under the fabric knots. Rectangular patterning was obtained even for 20 μm PS spheres. Polyester fabrics with other opening geometries and sizes (~300–1000 μm) or with higher fiber elasticity also allowed the formation of similar PCCs, some having curved prismatic walls. A higher colloid concentration (10–20%) induces the formation of thicker walls with fiber-negative replica morphology. Additionally, thick-wall PCCs (~100 μm) with semi-cylindrical morphology were obtained using SiO2 sub-microspheres and a wavy fabric. The colloidal pattern was used as a lithographic mask for natural lithography and as a template for the synthesis of triangular-prism-shaped inverted opals.

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Waag, Friedrich, René Streubel, Bilal Gökce et Stephan Barcikowski. « Synthesis of gold, platinum, and gold-platinum alloy nanoparticle colloids with high-power megahertz-repetition-rate lasers : the importance of the beam guidance method ». Applied Nanoscience 11, n^o 4 (11 février 2021) : 1303–12. http://dx.doi.org/10.1007/s13204-021-01693-y.

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AbstractNanoparticles of noble metals and their alloys are of particular interest for biomedicine and catalysis applications. The method of laser ablation of bulk metals in liquids gives facile access to such particles as high-purity colloids and is already used in industrial research. However, the method still lacks sufficient productivity for industrial implementation into series production. The use of innovative laser technology may help to further disseminate this colloid synthesis method in the near future. Ultrashort-pulsed lasers with high powers and megahertz-repetition-rates became available recently, but place high demands on the accurate optical laser pulse delivery on the target. Full lateral pulse separation is necessary to avoid a reduction of nanoparticle productivity due to pulse shielding. In this study, we compare flexible but rather slow galvanometer scanning with much faster but more expensive polygon-wheel scanning in their performance in the production of colloidal nanoparticles by laser ablation in liquid. Both beam guidance technologies are applied in the laser ablation of gold, platinum, and a gold-rich platinum alloy in micromolar saline water. We found that the dimensions of the scan pattern are crucial. A threshold pattern length exists, at which one scan technology becomes more productive than the other one. In addition, a much lower productivity was found for the ablation of gold compared to that of platinum. Alloying gold with only 10 at.% of platinum improved the productivity nearly to the level of platinum, reaching 8.3 g/h.

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Astuti, Mikrajuddin Abdullah et Khairurrijal. « Synthesis of Luminescent Ink from Europium-Doped Y2O3 Dispersed in Polyvinyl Alcohol Solution ». Advances in OptoElectronics 2009 (8 juin 2009) : 1–8. http://dx.doi.org/10.1155/2009/918351.

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Luminescent ink from europium-doped Y2O3 ( Y2O3:Eu) has been synthesized by two steps method: first, synthesis of luminescent powder of Y2O3:Eu by simple heating of metallic nitrates in a polymer solution and second, dispersing the powder in a polyvinyl alcohol (PVA) solution. The stability of the ink (luminescent colloid) was strongly affected by mixing process of the powder and the solution. Mixing process must be performed for a long time (about 8 hours) at above room temperature to product stable colloids. We observed that mixing at 30–40∘C resulted in a stable and highly dispersed colloid. The writing test was performed on a white paper to show the potential use of the colloid for making security codes.

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Jovanovic, Svetlana, Zoran Markovic, Duska Kleut, Vladimir Trajkovic, Branka Babic-Stojic, Miroslav Dramicanin et Todorovic Markovic. « Singlet oxygen generation by higher fullerene-based colloids ». Journal of the Serbian Chemical Society 75, n^o 7 (2010) : 965–73. http://dx.doi.org/10.2298/jsc090617062j.

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In this paper, the results of the synthesis and characterization of higher fullerene-based colloids is presented. The generation of singlet oxygen 1O2 (1?g) by fullerene water-based colloids (nC60, nC70 and nC84) was investigated. It was found by electron paramagnetic resonance spectroscopy that the generation of singlet oxygen was the highest by the nC84 colloid. The amplitude of the electron paramagnetic resonance (EPR) signal was two orders of magnitude higher than the amplitude of the EPR signals which originated from nC60 and nC70. The surface morphology and the structure of the particles of the water-based colloids were investigated by atomic force microscopy (AFM). The AFM study showed that the average size of the nC60, nC70 and nC84 were 200 nm, 80 nm and 70 nm, respectively. In addition, the particle size distribution of the nC60, nC70 and nC84 colloids was determined by dynamic light scattering (DLS) measurements.

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Mushtaq, Khizar, Pui May Chou et Chin Wei Lai. « Review on the Synthesis Methods of Nano-Tungsten Oxide Dihydrate Colloid ». MATEC Web of Conferences 335 (2021) : 03008. http://dx.doi.org/10.1051/matecconf/202133503008.

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Tungsten being a transition element, forms oxide compounds of various oxidation states that enables it to form nanocolloids of tungsten oxide dihydrate. Multiple methods have been used in recent years to synthesize nano tungsten oxide dihydrate, including sol-gel synthesis, electrochemical deposition, hydrothermal synthesis and anodization. However, a universally accepted synthesis method for this material is not offered. The most appropriate method and its corresponding processing parameters for the synthesis of nano tungsten oxide dihydrate colloids were presented in the present study. The objective of the present study was to investigate the effect of processing parameters, i.e. applied voltage, temperature and anodizing duration on the particle size of nanocolloids. It is found that anodization is the easiest, efficient, and cost-effective method to synthesize the colloidal solution of nano tungsten oxide dihydrate. Conducting the synthesis at room temperature at a voltage of 50 V for 60 minutes yields the product with particle size of 40 – 60 nm, which can be used in wide array of applications. This paper also highlights the research gaps for future work and gives recommendations to extend this study particularly for the industrial application of tungsten oxide.

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Pan, Guisheng, Albert S. Tse, R. Kesavamoorthy et Sanford A. Asher. « Synthesis of Highly Fluorinated Monodisperse Colloids for Low Refractive Index Crystalline Colloidal Arrays ». Journal of the American Chemical Society 120, n^o 26 (juillet 1998) : 6518–24. http://dx.doi.org/10.1021/ja9804823.

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Troyano, Javier, Arnau Carné-Sánchez, Civan Avci, Inhar Imaz et Daniel Maspoch. « Colloidal metal–organic framework particles : the pioneering case of ZIF-8 ». Chemical Society Reviews 48, n^o 23 (2019) : 5534–46. http://dx.doi.org/10.1039/c9cs00472f.

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Margheri, Giancarlo, Silvana Trigari, Mariabeatrice Berti, Maurizio Muniz Miranda et Rita Traversi. « Chitosan-Capped Au Nanoparticles for Laser Photothermal Ablation Therapy : UV-Vis Characterization and Optothermal Performances ». Journal of Spectroscopy 2018 (10 juillet 2018) : 1–11. http://dx.doi.org/10.1155/2018/8271254.

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We have reported on the synthesis and characterization of near-infrared- (NIR-) absorbing colloidal nanoparticles prepared by exploiting the one-step reaction of HAuCl4 and Na2S2O3, followed by their stabilization with chitosan. This reaction also produces a big amount of unwanted nanoparticles detuned with respect to the NIR spectral region. For this reason, it is usually assumed that the product has to be filtered and enriched to enhance its NIR absorption, and the possible exploitation of the simpler raw product has never been worthy to be considered. Aiming to investigate this missing aspect, we chose to avoid the purification steps and rather focused on the preparation of the unrefined colloid, identifying the synthesis conditions that maximize its NIR absorbance and, subsequently, testing it as an optothermal transducer by measuring its molar heating rate (MHR). As expected, we found that the performances of the raw colloid are indeed lower than those of its refined version, but only to a limited extent. Moreover, MHR is unexpectedly higher than that deducible for other classical NIR-absorbing nanoparticles, like Au nanorods or Au nanostars. Thus, the product of the simpler preparation protocol appears as a competitive trade-off solution between easy manufacturing and optothermal performances.

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Bollhorst, Tobias, Kurosch Rezwan et Michael Maas. « Colloidal capsules : nano- and microcapsules with colloidal particle shells ». Chemical Society Reviews 46, n^o 8 (2017) : 2091–126. http://dx.doi.org/10.1039/c6cs00632a.

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