Journal articles: 'Nanoparticle formation'

1

Shannahan, Jonathan. "The biocorona: a challenge for the biomedical application of nanoparticles." Nanotechnology Reviews 6, no. 4 (August 28, 2017): 345–53. http://dx.doi.org/10.1515/ntrev-2016-0098.

Full text

Abstract:

AbstractFormation of the biocorona on the surface of nanoparticles is a significant obstacle for the development of safe and effective nanotechnologies, especially for nanoparticles with biomedical applications. Following introduction into a biological environment, nanoparticles are rapidly coated with biomolecules resulting in formation of the nanoparticle-biocorona. The addition of these biomolecules alters the nanoparticle’s physicochemical characteristics, functionality, biodistribution, and toxicity. To synthesize effective nanotherapeutics and to more fully understand possible toxicity following human exposures, it is necessary to elucidate these interactions between the nanoparticle and the biological media resulting in biocorona formation. A thorough understanding of the mechanisms by which the addition of the biocorona governs nanoparticle-cell interactions is also required. Through elucidating the formation and the biological impact of the biocorona, the field of nanotechnology can reach its full potential. This understanding of the biocorona will ultimately allow for more effective laboratory screening of nanoparticles and enhanced biomedical applications. The importance of the nanoparticle-biocorona has been appreciated for a decade; however, there remain numerous future directions for research which are necessary for study. This perspectives article will summarize the unique challenges presented by the nanoparticle-biocorona and avenues of future needed investigation.

APA, Harvard, Vancouver, ISO, and other styles

2

Karim, Mohammad Ziaul, Md Eaqub Ali, and Sharifah Bee Abd Hamid. "Temperature Induced Formation of Goethite from Magnetite." Advanced Materials Research 1109 (June 2015): 191–94. http://dx.doi.org/10.4028/www.scientific.net/amr.1109.191.

Full text

Abstract:

Over the past few decades, magnetite nanoparticle has been profusely because of their wide range of applications. The co-precipitation method is the simplest and suitable method for the preparation of this nanoparticle. It goes through several reaction steps for the formation of various phases of magnetic nanoparticles. Goethite (FeO(OH)), is one of the intermediates, and it drastically suppressed with the magnetic properties of the Fe oxide phase. In our study, it was shown that at 30°C temperature pure magnetic nanoparticles is formed. But when precipitation temperature is increase to 80°C, goethite is also present with the magnetite nanoparticle. Hence, it is deduced that precipitation temperature plays a significant role in accelerating goethite phase formation when synthesising magnetite nanoparticle by this precipitation method. Data obtained from Raman spectroscopy and XRD supported the above observation.

APA, Harvard, Vancouver, ISO, and other styles

3

SOBHAN, M. A., M. AMS, M. J. WITHFORD, and E. M. GOLDYS. "FORMATION OF COLLOIDAL GOLD NANOPARTICLES BY USING FEMTOSECOND LASER ABLATION." International Journal of Nanoscience 08, no. 01n02 (February 2009): 209–12. http://dx.doi.org/10.1142/s0219581x09005712.

Full text

Abstract:

Colloidal gold nanoparticles were produced by irradiating a gold disc with a femtosecond laser beam in pure deionized water. Variation of laser fluence between 38 and 330 J/cm2 was used to control the nanoparticle size distribution. The nanoparticles produced were spherically shaped with average diameter between 9 and 10 nm. The effect of ablation time on the nanoparticle production efficiency and size distribution was also studied.

APA, Harvard, Vancouver, ISO, and other styles

4

Fomenko, Elena, Igor Altman, and Igor E. Agranovski. "Effect of External Charging on Nanoparticle Formation in a Flame." Materials 14, no. 11 (May 28, 2021): 2891. http://dx.doi.org/10.3390/ma14112891.

Full text

Abstract:

This paper attempts to demonstrate the importance of the nanoparticle charge in the synthesis flame, for the mechanism of their evolution during formation processes. An investigation was made of MgO nanoparticles formed during combustion of magnesium particles. The cubic shape of nanoparticles in an unaffected flame allows for direct interpretation of results on the external flame charging, using a continuous unipolar emission of ions. It was found that the emission of negative ions applied to the flame strongly affects the nanoparticle shape, while the positive ions do not lead to any noticeable change. The demonstrated effect emphasizes the need to take into account all of the phenomena responsible for the particle charge when modeling the nanoparticle formation in flames.

APA, Harvard, Vancouver, ISO, and other styles

5

Ahmadi, R., Madaah Hosseini, and A. Masoudi. "Avrami behavior of magnetite nanoparticles formation in co-precipitation process." Journal of Mining and Metallurgy, Section B: Metallurgy 47, no. 2 (2011): 211–18. http://dx.doi.org/10.2298/jmmb110330010a.

Full text

Abstract:

In this work, magnetite nanoparticles (mean particle size about 20 nm) were synthesized via coprecipitation method. In order to investigate the kinetics of nanoparticle formation, variation in the amount of reactants within the process was measured using pH-meter and atomic absorption spectroscopy (AAS) instruments. Results show that nanoparticle formation behavior can be described by Avrami equations. Transmission electron microscopy (TEM) and X-ray diffraction (XRD) were performed to study the chemical and morphological characterization of nanoparticles. Some simplifying assumptions were employed for estimating the nucleation and growth rate of magnetite nanoparticles.

APA, Harvard, Vancouver, ISO, and other styles

6

Majerič, Peter, and Rebeka Rudolf. "Advances in Ultrasonic Spray Pyrolysis Processing of Noble Metal Nanoparticles—Review." Materials 13, no. 16 (August 7, 2020): 3485. http://dx.doi.org/10.3390/ma13163485.

Full text

Abstract:

In the field of synthesis and processing of noble metal nanoparticles, the study of the bottom-up method, called Ultrasonic Spray Pyrolysis (USP), is becoming increasingly important. This review analyses briefly the features of USP, to underline the physical, chemical and technological characteristics for producing nanoparticles and nanoparticle composites with Au and Ag. The main aim is to understand USP parameters, which are responsible for nanoparticle formation. There are two nanoparticle formation mechanisms in USP: Droplet-To-Particle (DTP) and Gas-To-Particle (GTP). This review shows how the USP process is able to produce Au, Ag/TiO2, Au/TiO2, Au/Fe2O3 and Ag/(Y0.95 Eu0.05)2O3 nanoparticles, and presents the mechanisms of formation for a particular type of nanoparticle. Namely, the presented Au and Ag nanoparticles are intended for use in nanomedicine, sensing applications, electrochemical devices and catalysis, in order to benefit from their properties, which cannot be achieved with identical bulk materials. The development of new noble metal nanoparticles with USP is a constant goal in Nanotechnology, with the objective to obtain increasingly predictable final properties of nanoparticles.

APA, Harvard, Vancouver, ISO, and other styles

7

Sidorova, Elena N., Ella L. Dzidziguri, Yulia P. Vinichenko, Dmitriy Yu Ozherelkov, Alexander S. Shinkaryov, Alexander A. Gromov, and Anton Yu Nalivaiko. "Metal Nanoparticles Formation from Nickel Hydroxide." Materials 13, no. 20 (October 21, 2020): 4689. http://dx.doi.org/10.3390/ma13204689.

Full text

Abstract:

In this study, the mechanism of nickel nanoparticle formation from its hydroxide was analyzed. Metallic nickel nanoparticles were obtained through the hydroxide’s reduction under hydrogen. Nickel hydroxides were produced from nickel (II) nitrate hexahydrate and NaOH by deposition under various initial conditions. The influence of washing treatment on the dispersion of obtained nickel powders was studied. The washing procedure of precipitates was carried out by centrifugation, ultrasonic treatment, and decantation. X-ray diffractometry, transmission electron microscopy, low-temperature nitrogen adsorption, infrared spectroscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy methods were used for nanoparticle characterization. Based on the resulting data, a model of the Ni(OH)2 aggregate structure after deposition was proposed. The number of nickel hydroxide particles required to form one nickel nanoparticle was estimated, and a model of its formation was proposed.

APA, Harvard, Vancouver, ISO, and other styles

8

Wang, Kun, Yuqing Zhang, Lincun Jiang, Zhiyuan Li, Xin Wang, Jinwei Zhai, and Siao Zhang. "Understanding the effect of ambient gas pressure on the nanoparticle formation in electrically exploding wires." Physics of Plasmas 30, no. 3 (March 2023): 033511. http://dx.doi.org/10.1063/5.0120712.

Full text

Abstract:

In this paper, a computational model characterizing the preparation of metallic nanoparticles by electrically exploding wires from the onset of current flowing through the wire to the final moment of nanoparticle formation in a gaseous environment is constructed. The computational model consists of a 1D magnetohydrodynamic model, a simplified magnetohydrodynamic model with two-temperature approximation, and a set of general dynamic equations based on the nodal approach, corresponding to the phase transition stage, plasma evolution stage, and nanoparticle growth stage, respectively. The numerical investigation on the formation of nanoparticles is performed with “cold-start” conditions. The computational predictions for the dependence of nanoparticle size on proportion under argon gas pressure of 10 kPa demonstrate that the nanoparticles of 21 nm in diameter account for the maximum proportion of 4.3%. It coincides with the experimental measurements for nanoparticles of 19 nm in diameter with the maximum proportion of 3.5%. The computational model is employed to reveal the influence of ambient gas pressures on the process of nanoparticle formation. The variation trends for parameters of exploding products, cooling rate, and nanoparticle diameter with the largest proportion on ambient gas pressures are discussed. The size distribution of nanoparticles under different argon gas pressures matches relatively well with relevant experimental data. This computational model bridges the gap between the electrically exploding wires and the growth of nanoparticles, providing theoretical support for the regulation and control technology in nanoparticle synthesization by electrically exploding wires.

APA, Harvard, Vancouver, ISO, and other styles

9

Borchardt, John K. "Controlling nanoparticle formation." Materials Today 8, no. 6 (June 2005): 15. http://dx.doi.org/10.1016/s1369-7021(05)70927-5.

Full text

APA, Harvard, Vancouver, ISO, and other styles

10

Lee, Hwankyu. "Molecular Modeling of Protein Corona Formation and Its Interactions with Nanoparticles and Cell Membranes for Nanomedicine Applications." Pharmaceutics 13, no. 5 (April 29, 2021): 637. http://dx.doi.org/10.3390/pharmaceutics13050637.

Full text

Abstract:

The conformations and surface properties of nanoparticles have been modified to improve the efficiency of drug delivery. However, when nanoparticles flow through the bloodstream, they interact with various plasma proteins, leading to the formation of protein layers on the nanoparticle surface, called protein corona. Experiments have shown that protein corona modulates nanoparticle size, shape, and surface properties and, thus, influence the aggregation of nanoparticles and their interactions with cell membranes, which can increases or decreases the delivery efficiency. To complement these experimental findings and understand atomic-level phenomena that cannot be captured by experiments, molecular dynamics (MD) simulations have been performed for the past decade. Here, we aim to review the critical role of MD simulations to understand (1) the conformation, binding site, and strength of plasma proteins that are adsorbed onto nanoparticle surfaces, (2) the competitive adsorption and desorption of plasma proteins on nanoparticle surfaces, and (3) the interactions between protein-coated nanoparticles and cell membranes. MD simulations have successfully predicted the competitive binding and conformation of protein corona and its effect on the nanoparticle–nanoparticle and nanoparticle–membrane interactions. In particular, simulations have uncovered the mechanism regarding the competitive adsorption and desorption of plasma proteins, which helps to explain the Vroman effect. Overall, these findings indicate that simulations can now provide predications in excellent agreement with experimental observations as well as atomic-scale insights into protein corona formation and interactions.

APA, Harvard, Vancouver, ISO, and other styles

11

Borgatta, Jaya R., Christian A. Lochbaum, Wade H. Elmer, Jason C. White, Joel A. Pedersen, and Robert J. Hamers. "Biomolecular corona formation on CuO nanoparticles in plant xylem fluid." Environmental Science: Nano 8, no. 4 (2021): 1067–80. http://dx.doi.org/10.1039/d1en00140j.

Full text

APA, Harvard, Vancouver, ISO, and other styles

12

Westmeier, Dana, Djamschid Solouk-Saran, Cecilia Vallet, Svenja Siemer, Dominic Docter, Hermann Götz, Linda Männ, et al. "Nanoparticle decoration impacts airborne fungal pathobiology." Proceedings of the National Academy of Sciences 115, no. 27 (June 20, 2018): 7087–92. http://dx.doi.org/10.1073/pnas.1804542115.

Full text

Abstract:

Airborne fungal pathogens, predominantly Aspergillus fumigatus, can cause severe respiratory tract diseases. Here we show that in environments, fungal spores can already be decorated with nanoparticles. Using representative controlled nanoparticle models, we demonstrate that various nanoparticles, but not microparticles, rapidly and stably associate with spores, without specific functionalization. Nanoparticle-spore complex formation was enhanced by small nanoparticle size rather than by material, charge, or “stealth” modifications and was concentration-dependently reduced by the formation of environmental or physiological biomolecule coronas. Assembly of nanoparticle-spore surface hybrid structures affected their pathobiology, including reduced sensitivity against defensins, uptake into phagocytes, lung cell toxicity, and TLR/cytokine-mediated inflammatory responses. Following infection of mice, nanoparticle-spore complexes were detectable in the lung and less efficiently eliminated by the pulmonary immune defense, thereby enhancing A. fumigatus infections in immunocompromised animals. Collectively, self-assembly of nanoparticle-fungal complexes affects their (patho)biological identity, which may impact human health and ecology.

APA, Harvard, Vancouver, ISO, and other styles

13

Yang, Wen, Lin Wang, Evan M. Mettenbrink, Paul L. DeAngelis, and Stefan Wilhelm. "Nanoparticle Toxicology." Annual Review of Pharmacology and Toxicology 61, no. 1 (January 6, 2021): 269–89. http://dx.doi.org/10.1146/annurev-pharmtox-032320-110338.

Full text

Abstract:

Nanoparticles from natural and anthropogenic sources are abundant in the environment, thus human exposure to nanoparticles is inevitable. Due to this constant exposure, it is critically important to understand the potential acute and chronic adverse effects that nanoparticles may cause to humans. In this review, we explore and highlight the current state of nanotoxicology research with a focus on mechanistic understanding of nanoparticle toxicity at organ, tissue, cell, and biomolecular levels. We discuss nanotoxicity mechanisms, including generation of reactive oxygen species, nanoparticle disintegration, modulation of cell signaling pathways, protein corona formation, and poly(ethylene glycol)-mediated immunogenicity. We conclude with a perspective on potential approaches to advance current understanding of nanoparticle toxicity. Such improved understanding may lead to mitigation strategies that could enable safe application of nanoparticles in humans. Advances in nanotoxicity research will ultimately inform efforts to establish standardized regulatory frameworks with the goal of fully exploiting the potential of nanotechnology while minimizing harm to humans.

APA, Harvard, Vancouver, ISO, and other styles

14

Bremmer, G. Marien, Eirini Zacharaki, Anja O. Sjåstad, Violeta Navarro, Joost W. M. Frenken, and Patricia J. Kooyman. "In situ TEM observation of the Boudouard reaction: multi-layered graphene formation from CO on cobalt nanoparticles at atmospheric pressure." Faraday Discussions 197 (2017): 337–51. http://dx.doi.org/10.1039/c6fd00185h.

Full text

Abstract:

Using a MEMS nanoreactor in combination with a specially designed in situ Transmission Electron Microscope (TEM) holder and gas supply system, we imaged the formation of multiple layers of graphene encapsulating a cobalt nanoparticle, at 1 bar CO : N₂ (1 : 1) and 500 °C. The cobalt nanoparticle was imaged live in a TEM during the Boudouard reaction. The in situ/operando TEM studies give insight into the behaviour of the catalyst at the nanometer-scale, under industrially relevant conditions. When switching from Fischer–Tropsch syngas conditions (CO : H₂ : N₂ 1 : 2 : 3 at 1 bar) to CO-rich conditions (CO : N₂ 1 : 1 at 1 bar), we observed the formation of multi-layered graphene on Co nanoparticles at 500 °C. Due to the high temperature, the surface of the Co nanoparticles facilitated the Boudouard reaction, causing CO dissociation and the formation of layers of graphene. After the formation of the first patches of graphene at the surface of the nanoparticle, more and more layers grew over the course of about 40 minutes. In its final state, around 10 layers of carbon capped the nanoparticle. During this process, the carbon shell caused mechanical stress in the nanoparticle, inducing permanent deformation.

APA, Harvard, Vancouver, ISO, and other styles

15

Dhar, Sunandan, Vishesh Sood, Garima Lohiya, Harini Deivendran, and Dhirendra S. Katti. "Role of Physicochemical Properties of Protein in Modulating the Nanoparticle-Bio Interface." Journal of Biomedical Nanotechnology 16, no. 8 (August 1, 2020): 1276–95. http://dx.doi.org/10.1166/jbn.2020.2958.

Full text

Abstract:

Nanoparticles, on exposure to the biological milieu, tend to interact with macromolecules to form a biomolecular corona. The biomolecular corona confers a unique biological identity to nanoparticles, and its protein composition plays a deterministic role in the biological fate of nanoparticles. The physiological behavior of proteins stems from their physicochemical properties, including surface charge, hydrophobicity, and structural stability. However, there is insufficient understanding about the role of physicochemical properties of proteins in biomolecular corona formation. We hypothesized that the physicochemical properties of proteins would influence their interaction with nanoparticles and have a deterministic effect on nanoparticle-cell interactions. To test our hypothesis, we used model proteins from different structural classes to understand the effect of secondary structure elements of proteins on the nanoparticle-protein interface. Further, we modified the surface of proteins to study the role of protein surface characteristics in governing the nanoparticle-protein interface. For this study, we used mesoporous silica nanoparticles as a model nanoparticle system. We observed that the surface charge of proteins governs the nature of the primary interaction and the extent of subsequent secondary interactions causing structural rearrangements of the protein. We also observed that the secondary structural contents of proteins significantly affected both the extent of secondary interactions at the nanoparticle-protein interface and the dispersion state of the nanoparticle-protein complex. Further, we studied the interactions of different protein-coated nanoparticles with different cells (fibroblast, carcinoma, and macrophage). We observed that different cells internalized the nanoparticle-protein complex as a function of secondary structural components of the protein. The type of model protein had a significant effect on their internalization by macrophages. Overall, we observed that the physicochemical characteristics of proteins had a significant role in modulating the nanoparticle-bio-interface at the level of both biomolecular corona formation and nanoparticle internalization by cells.

APA, Harvard, Vancouver, ISO, and other styles

16

Saif Hasan, Syed, Sanjay Singh, Rasesh Y. Parikh, Mahesh S. Dharne, Milind S. Patole, B. L. V. Prasad, and Yogesh S. Shouche. "Bacterial Synthesis of Copper/Copper Oxide Nanoparticles." Journal of Nanoscience and Nanotechnology 8, no. 6 (June 1, 2008): 3191–96. http://dx.doi.org/10.1166/jnn.2008.095.

Full text

Abstract:

A bacterial mediated synthesis of copper/copper oxide nanoparticle composite is reported. A Gram-negative bacterium belonging to the genus Serratia was isolated from the midgut of Stibara sp., an insect of the Cerambycidae family of beetles found in the Northwestern Ghats of India. This is a unique bacterium that is quite specific for the synthesis of copper oxide nanoparticles as several other strains isolated from the same insect and common Indian mosquitoes did not result in nanoparticle formation. By following the reaction systematically, we could delineate that the nanoparticle formation occurs intracellularly. However, the process results in the killing of bacterial cells. Subsequently the nanoparticles leak out as the cell wall disintegrates. The nanoparticles formed are thoroughly characterized by UV-Vis, TEM, XRD, XPS and FTIR studies.

APA, Harvard, Vancouver, ISO, and other styles

17

Landry, Markita P. "Protein Corona Formation on Hard and Polymeric Nanoparticles – Towards Understanding Biocompatibility, Biodistribution, and Efficacy." ECS Meeting Abstracts MA2022-01, no. 8 (July 7, 2022): 707. http://dx.doi.org/10.1149/ma2022-018707mtgabs.

Full text

Abstract:

Unpredictable protein adsorption on both hard and soft nanoparticles remains a considerable challenge towards effectively applying nanotechnologies in biological environments. Hard nanoparticles form the basis of many chemical nanosensors. Conversely, soft nanoparticles such as lipid nanoparticles (LNPs) are vital for the successful delivery of mRNA-based vaccines, and offer promising applications in neonatal gene therapy, immunotherapy, and protein replacement therapy. Understanding the biological interactions that both hard and soft nanoparticles undergo upon introduction into biological systems is central to optimize the outcomes of nanoparticle-based delivery biotechnologies in clinical settings. Herein, we present a multimodal study of protein corona composition and dynamics, first on ‘hard’ nanoparticles: spherical polystyrene nanoparticles (a previously studied model nanoparticle) and high aspect ratio single-walled carbon nanotubes (SWCNTs, an understudied nanoparticle). These nanoparticles are exposed to two biofluids of interest: blood plasma (relevant for intravenous applications) and cerebrospinal fluid (relevant for brain imaging and sensing applications). To study these protein coronas, we develop a methodology based on quantitative proteomic mass spectrometry [1] and chemical thermodynamic analysis of real-time protein binding to identify protein corona ‘fingerprints’, enabling quantification of protein abundance and enrichment/depletion relative to the native biofluid, transient kinetics [2], and end-state topology. Interestingly, we find that the heavily studied polystyrene nanoparticles are relatively agnostic in the formation of their protein coronas, demonstrating little preference for particular protein classes or physicochemical properties. Conversely, we find that SWCNTs show strong preference for certain protein classes. Our additional work in machine learing-based analysis shows that corona compositions, and more broadly nanoparticle biofouling, can be drastically different for each nanoparticle type [3]. Lastly, we study nano-bio interactions encountered by ‘soft’ nanoparticles: LNPs commonly used for the therapeutic delivery of mRNA. We investigate how modifying (i) the mRNA packaged inside the LNPs and (ii) the ionizable lipid within the LNPs modulate the subsequently formed protein corona in (iii) various biological environments of relevance for delivery applications. Importantly, this workflow is readily translatable across soft polymer-based nanotechnologies of interest, which are understudied due to the experimental complexity of separating nanoparticle-corona complexes from free proteins. This fundamental understanding of protein-LNP interactions could enable more seamless design and clinical application of next-generation LNP carriers to bolster the safe and effective delivery of mRNA and other therapeutics to patients. References Pinals, R.L., et al., Quantitative Protein Corona Composition and Dynamics on Carbon Nanotubes in Biological Environments. Angewandte Chemie (2020). Pinals, R. L., Yang, D., Lui, A., Cao, W. & Landry, M. P. Corona Exchange Dynamics on Carbon Nanotubes by Multiplexed Fluorescence Monitoring. JACS (2020). Ouassil, N.*, Pinals, R.L.*, O’Donnell, J.T.D., Wang, J., Landry, M.P.‡ Supervised Learning Model to Predict Protein Adsorption to Nanoparticles. Science Advances (2022).

APA, Harvard, Vancouver, ISO, and other styles

18

Carpenter, Chris. "Surface-Modified Nanoparticle Gelled-Acid System Stimulates Without Formation Damage." Journal of Petroleum Technology 74, no. 06 (June 1, 2022): 64–66. http://dx.doi.org/10.2118/0622-0064-jpt.

Full text

Abstract:

This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper IPTC 22443, “Surface-Modified Nanoparticle-Based Novel Gelled-Acid System: A Unique Formation-Damage-Free Well-Stimulation Technology,” by Rajendra Kalgaonkar, SPE, and Nour Baqader, SPE, Saudi Aramco. The paper has not been peer reviewed. Copyright 2022 International Petroleum Technology Conference. Reproduced by permission. Gelled-acid systems based on the gelation of hydrochloric acid (HCl) are used extensively in both matrix and fracture acidizing to prevent acidizing-fluid leakoff. However, these systems can lead to formation damage. To mitigate this risk, the authors have developed a self-breaking, formation-damage-free, novel nanoparticle-based gelled-acid system to replace polymer-based gelled-acid systems. Nanoparticle-Based Gelled-Acid System The complete paper showcases a method for gelling up an acid formulation for stimulating a carbonate reservoir. The technique is based on surface-modified nanoparticles. The new gelled-acid system does not contain any polymer-based gelling agents. It consists of inorganic nanoparticles with a gelation-activator material to activate viscosification. The increase in viscosity will lead to a slowdown of the reaction rate of the acid with the carbonate formation. Suitable functionalities are used to surface-modify the nanoparticles to stabilize them in acidic media. The treatment fluid can be pumped downhole as a single homogeneous fluid system in the same pumping stage. The nanoparticles are easily miscible with the acid formulation without any need for the batch-mixing processes that may be required for a polymer-based gelled-acid system to account for polymer hydration. Thus, this formulation can be mixed easily while pumping the acidic fluid downhole. This ensures that the new gelled-acid system can increase operational efficiency by reducing operational time substantially. Nanoparticle gelation takes place in situ in the acid fluid and does not require a separate pumping stage to introduce the activator. The gelation of nanoparticles is predominantly a pH-based phenomenon. The gelation rate can be influenced also by temperature. As the fluid’s temperature increases, the treatment fluid viscosifies, thus diverting the tail-end acid to less-permeable zones in the reservoir. As the acid spends after reacting with the carbonate formation and the pH of the system increases beyond a pH of 4, the nanoparticles lose their ability to further viscosify the acid, thus reducing the viscosity of the fluid system. This enables easy flowback of the fluid post-treatment. Because the viscosifying material used in the present invention is a nanoparticulate, it will be potentially nondamaging to the formation because of effective flowback and no residual deposition inside the formation.

APA, Harvard, Vancouver, ISO, and other styles

19

LIU, JIN-KU, YI LU, XIAO-JUN HU, and JIN MU. "FACILE SYNTHESIS OF COPPER NANOPARTICLE CHAINS." Nano 02, no. 01 (February 2007): 31–34. http://dx.doi.org/10.1142/s1793292007000337.

Full text

Abstract:

The copper nanoparticle chains have been synthesized through a self-assembly process with sodium polymethacylic acid as the template. The resulted nanoparticle chains were 0.8–1.5 μm long, and the composed nanoparticles were about 30 nm in diameter. The self-assembly formation mechanism has been proposed.

APA, Harvard, Vancouver, ISO, and other styles

20

Tien, Der-Chi, Liang-Chia Chen, Nguyen Van Thai, and Sana Ashraf. "Study of Ag and Au Nanoparticles Synthesized by Arc Discharge in Deionized Water." Journal of Nanomaterials 2010 (2010): 1–9. http://dx.doi.org/10.1155/2010/634757.

Full text

Abstract:

The paper presents a study of Ag and Au nanofluids synthesized by the arc discharge method (ADM) in deionized water. The metallic Ag nanoparticle (Ag0) and ionic Ag (Ag+) have played an important role in the battle against germs which are becoming more drug-resistant every year. Our study indicates that Ag nanoparticle suspension (SNPS) fabricated by using ADM without added surfactants exclusively contains the metallic Ag nanoparticle and ionic Ag. Besides that, the ADM in deionized water has also been employed for the fabrication process of Au nanoparticles. The experimental results indicate that the prepared Ag nanoparticles can react with the dissolvedH2CO3in deionized water, leading to the formation ofAg2CO3. Significantly different to Ag, the prepared Au nanoparticles with their surfaces bonded by oxygen are suspended in deionized water by the formation of hydrogen bonded with the neighboring water molecules.

APA, Harvard, Vancouver, ISO, and other styles

21

Du, H., and F. Yu. "Nanoparticle formation in the exhaust of vehicles running on ultra-low sulfur fuel." Atmospheric Chemistry and Physics 8, no. 16 (August 18, 2008): 4729–39. http://dx.doi.org/10.5194/acp-8-4729-2008.

Full text

Abstract:

Abstract. The concern of adverse health impacts from exposure to vehicle-emitted nanoparticles has been escalating over the past few years. In order to meet more stringent EPA emission standards for particle mass emissions, advanced exhaust after-treatment systems such as continuously regenerating diesel particle filters (CRDPFs) have to be employed on vehicles and fuel with ultra-low sulfur is to be used. Although CRDPFs were found to be effective in reducing particle mass emissions, they were revealed to increase the potential of volatile nanoparticle formation. Significant nanoparticle concentrations have also been detected for vehicles running on ultra-low sulfur fuel but without CRDPFs. The main focus of this paper is the formation and evolution of nanoparticles in an exhaust plume under ultra-low sulfur conditions. Such a study is necessary to project future nanoparticle emissions as fuel compositions and after-treatment systems change. We have carried out a comprehensive quantitative assessment of the effects of enhanced sulfur conversion efficiency, sulfur storage/release, and presence of non-volatile cores on nanoparticle formation using a detailed composition resolved aerosol microphysical model with a recently improved H2SO4-H2O homogeneous nucleation (BHN) module. Two well-controlled case studies show good agreement between model predictions and measurements in terms of particle size distribution and temperature dependence of particle formation rate, which leads us to conclude that BHN is the main source of nanoparticles for vehicles equipped with CRDPFs. We found that the employment of CRDPFs may lead to the higher number concentration of nanoparticles (but smaller size) in the exhaust of vehicles running on ultra-low sulfur fuel compared to those emitted from vehicles running on high sulfur fuel. We have also shown that the sulfate storage and release effect can lead to significant enhancement in nanoparticle production under favorable conditions. For vehicles running on ultra-low sulfur fuel but without CRDPFs, the BHN is negligible; however, the condensation of low volatile organic compounds on nanometer-sized non-volatile cores may explain the observed nucleation mode particles.

APA, Harvard, Vancouver, ISO, and other styles

22

Bellotto, Ottavia, Maria C. Cringoli, Siglinda Perathoner, Paolo Fornasiero, and Silvia Marchesan. "Peptide Gelators to Template Inorganic Nanoparticle Formation." Gels 7, no. 1 (February 2, 2021): 14. http://dx.doi.org/10.3390/gels7010014.

Full text

Abstract:

The use of peptides to template inorganic nanoparticle formation has attracted great interest as a green route to advance structures with innovative physicochemical properties for a variety of applications that range from biomedicine and sensing, to catalysis. In particular, short-peptide gelators offer the advantage of providing dynamic supramolecular environments for the templating effect on the formation of inorganic nanoparticles directly in the resulting gels, and ideally without using further reductants or chemical reagents. This mini-review describes the recent progress in the field to outline future research directions towards dynamic functional materials that exploit the synergy between supramolecular chemistry, nanoscience, and the interface between organic and inorganic components for advanced performance.

APA, Harvard, Vancouver, ISO, and other styles

23

Sánchez M., J. F., H. A. Ritacco, and M. D. Sánchez. "FORMATION OF PALLADIUM NANOPARTICLES BY THE POLYOL METHOD:INFLUENCE OF ALKALINE CONDITIONS." Anales AFA 33, no. 4 (January 15, 2023): 103–11. http://dx.doi.org/10.31527/analesafa.2022.33.4.103.

Full text

Abstract:

The effect of sodium hydroxide (NaOH) on the size of palladium (Pd) nanoparticles obtained by the simple polyol route was studied. Nanoparticles were synthesized at room temperature using palladium(II) chloride (PdCl2) and NaOH dissolved in ethylene glycol (EG) as reduction reaction promoters. No protective agents or stabilizers were used. We monitored the reaction kinetics and the growth of the nanoparticles by UV-vis spectroscopy and their crystallinity by powder X-ray diffraction (XRD) as a function of NaOH concentration. Crystallite size was evaluated from the diffraction pattern. We found that nanoparticle growth is strongly influenced by the NaOH: Pd molar ratio. Crystallite sizes from 2 to 24 nm were obtained for molar ratios ranging from 1 to 33. At lower concentrations of NaOH, the nucleation and growth process of the nanoparticles were found to be controlled by the reduction of the Pd ion precursors.At higher concentrations, the intermediate reduction of Pd-Cl-OH species determines the nanoparticle growth rate resulting in the formation of the smallest final-size nanoparticles.

APA, Harvard, Vancouver, ISO, and other styles

24

Zinicovscaia, Inga, Liudmila Rudi, Ana Valuta, Liliana Cepoi, Konstantin Vergel, Marina V. Frontasyeva, Alexey Safonov, Markus Wells, and Dmitrii Grozdov. "Biochemical Changes in Nostoc linckia Associated with Selenium Nanoparticles Biosynthesis." Ecological Chemistry and Engineering S 23, no. 4 (December 1, 2016): 559–69. http://dx.doi.org/10.1515/eces-2016-0039.

Full text

Abstract:

Abstract The cyanobacterium Nostoc linckia was used to study the biotechnology of selenium nanoparticles synthesis for the first time. The experimental conditions of the nanoparticle production by the studied cyanobacteria in aqueous cobalt selenite solutions were examined. Neutron activation analysis allowed characterization of the dynamics of accumulation of the total selenium quantity by Nostoc linckia. Scanning Electron Microscope images demonstrated extracellular formation of amorphous nanoparticles. Released selenium nanoparticles ranged in size from 10 to 80 nm. The changes of essential parameters of biomass (proteins, lipids, carbohydrates, and phycobilin) content during the nanoparticle formation were assessed. During the first 24 h of nanoparticle synthesis, a slight decline of proteins, lipids and carbohydrates content in the biomass was observed. The most extensive was the process of phycobilin degradation. Furthermore, all biochemical component content as well as an antioxidant activity of the biomass extracts significantly decreased. The obtained substance of Nostoc biomass with selenium nanoparticles may be used for medical, pharmaceutical and technological purposes.

APA, Harvard, Vancouver, ISO, and other styles

25

RAJASULOCHANA, P., R. DHAMOTHARAN, P. MURUGAKOOTHAN, S. MURUGESAN, and P. KRISHNAMOORTHY. "BIOSYNTHESIS AND CHARACTERIZATION OF GOLD NANOPARTICLES USING THE ALGA Kappaphycus alvarezii." International Journal of Nanoscience 09, no. 05 (October 2010): 511–16. http://dx.doi.org/10.1142/s0219581x10007149.

Full text

Abstract:

As a part of our ongoing investigation into the use of algae for gold nanoparticle synthesis, we screened the marine alga Kappaphycus alvarezii, to investigate its efficiency to reduce gold ions as well as the formation of gold nanoparticles. In the present work, we report the reaction condition of the alga K. alvarezii with aqueous gold ions for gold nanoparticle synthesis within the biomass extracellularly. The formation of gold nanoparticles was characterized by UV–Vis spectroscopy, Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) method. Moreover, we have found that the reaction of gold ions with the K. alvarezii biomass under stationary conditions results in the rapid extracellular formation of gold nanoparticles of spherical morphology. The gold nanoparticles are not toxic to the cells that continued to grow after the biosynthesis of the gold nanoparticles.

APA, Harvard, Vancouver, ISO, and other styles

26

Olarte-Plata, Juan D., Gøran Brekke-Svaland, and Fernando Bresme. "The influence of surface roughness on the adhesive interactions and phase behavior of suspensions of calcite nanoparticles." Nanoscale 12, no. 20 (2020): 11165–73. http://dx.doi.org/10.1039/d0nr00834f.

Full text

APA, Harvard, Vancouver, ISO, and other styles

27

Devi, S., B. Singh, A. K. Paul, and S. Tyagi. "Highly sensitive and selective detection of trinitrotoluene using cysteine-capped gold nanoparticles." Analytical Methods 8, no. 22 (2016): 4398–405. http://dx.doi.org/10.1039/c6ay01036a.

Full text

Abstract:

(A) A schematic representation of the formation of cysteine capped gold nanoparticles and their interaction at pH 5 and 9.3. (B) A schematic representation of the formation of a Meisenheimer complex between cysteine modified gold nanoparticles and TNT, and possible cross-linking between gold nanoparticles bound to the Meisenheimer complex with gold nanoparticle bound cysteine.

APA, Harvard, Vancouver, ISO, and other styles

28

Antony, Elizabath, Mythili Sathiavelu, and Sathiavelu Arunachalam. "SYNTHESIS OF SILVER NANOPARTICLES FROM THE MEDICINAL PLANT BAUHINIA ACUMINATA AND BIOPHYTUM SENSITIVUM–A COMPARATIVE STUDY OF ITS BIOLOGICAL ACTIVITIES WITH PLANT EXTRACT." International Journal of Applied Pharmaceutics 9, no. 1 (December 31, 2016): 22. http://dx.doi.org/10.22159/ijap.2017v9i1.16277.

Full text

Abstract:

Objective: The aim of current study was to synthesise silver nanoparticles from the leaf extracts (aqueous and methanol) of two medicinal plants Bauhinia acuminata and Biophytum sensitivum and to compare its biological activities with that of plant extract.Methods: Silver nanoparticles were synthesised, and it was characterised using UV-Visible spectroscopy and scanning electron microscope (SEM). Fourier transform infrared spectroscopy (FTIR) and GC-MS analysis were done for silver nanoparticle extract. The biological activities such as DPPH scavenging assay, haemolytic assay and antimicrobial assay were done for both nanoparticle and plant extract.Results: The UV-Visible spectroscopy showed the formation of nanoparticles in a size range of 400-460 nm. GC-MS analysis showed the presence of biologically active compounds like DL-alpha-tocopherol and Alpha-tocopherol-beta-D-mannose. FTIR analysis of silver nanoparticles and leaf extracts showed the formation of aldehydes, alkenes, amines, alcohols, etc., which confirmed the presence of the compounds present in plant extracts. SEM image showed the formation of nanoparticles of size 2 micrometre. Phytochemical analysis of plant extracts showed the presence of carbohydrates, phenols, flavonoids, saponins, tannins and terpenoids. The methanol extract of Bauhinia acuminata showed high DPPH scavenging activity of 90% compared to that of the silver nanoparticle. The percentage hemolysis of all extracts was found to be 6%-39%. The antimicrobial activity of leaf extracts showed excellent activity towards Bacillus cereus and Listeria monocytogens.Conclusion: The results of present study showed that the silver nanoparticle synthesised from the plant extract has many bioactive compounds and it was found to have significant biological activities but comparatively lesser than plant extract. It concludes the both plant and nanoparticle extract can be used as a potential resource for therapeutic purpose.

APA, Harvard, Vancouver, ISO, and other styles

29

Skountzos, Emmanuel N., Katerina S. Karadima, and Vlasis G. Mavrantzas. "Structure and Dynamics of Highly Attractive Polymer Nanocomposites in the Semi-Dilute Regime: The Role of Interfacial Domains and Bridging Chains." Polymers 13, no. 16 (August 16, 2021): 2749. http://dx.doi.org/10.3390/polym13162749.

Full text

Abstract:

Detailed molecular dynamics (MD) simulations are employed to study how the presence of adsorbed domains and nanoparticle bridging chains affect the structural, conformational, thermodynamic, and dynamic properties of attractive polymer nanocomposite melts in the semi-dilute regime. As a model system we have chosen an unentangled poly(ethylene glycol) (PEG) matrix containing amorphous spherical silica nanoparticles with different diameters and at different concentrations. Emphasis is placed on properties such as the polymer mass density profile around nanoparticles, the compressibility of the system, the mean squared end-to-end distance of PEG chains, their orientational and diffusive dynamics, the single chain form factor, and the scattering functions. Our analysis reveals a significant impact of the adsorbed, interfacial polymer on the microscopic dynamic and conformational properties of the nanocomposite, especially under conditions favoring higher surface-to-volume ratios (e.g., for small nanoparticle sizes at fixed nanoparticle loading, or for higher silica concentrations). Simultaneously, adsorbed polymer chains adopt graft-like conformations, a feature that allows them to considerably extend away from the nanoparticle surface to form bridges with other nanoparticles. These bridges drive the formation of a nanoparticle network whose strength (number of tie chains per nanoparticle) increases substantially with increasing concentration of the polymer matrix in nanoparticles, or with decreasing nanoparticle size at fixed nanoparticle concentration. The presence of hydroxyl groups at the ends of PEG chains plays a key role in the formation of the network. If hydroxyl groups are substituted by methoxy ones, the simulations reveal that the number of bridging chains per nanoparticle decreases dramatically, thus the network formed is less dense and less strong mechanically, and has a smaller impact on the properties of the nanocomposite. Our simulations predict further that the isothermal compressibility and thermal expansion coefficient of PEG-silica nanocomposites are significantly lower than those of pure PEG, with their values decreasing practically linear with increasing concentration of the nanocomposite in nanoparticles.

APA, Harvard, Vancouver, ISO, and other styles

30

Schroer, Martin A., Alexander Levish, Yasin Yildizlar, Maximilian Stepponat, and Markus Winterer. "A versatile chemical vapor synthesis reactor for in situ x-ray scattering and spectroscopy." Review of Scientific Instruments 93, no. 11 (November 1, 2022): 113706. http://dx.doi.org/10.1063/5.0122461.

Full text

Abstract:

We describe a versatile reactor system for chemical vapor synthesis of nanoparticles, which enables in situ investigations of high temperature gas phase particle formation and transformation processes by x-ray scattering and x-ray absorption spectroscopy. The system employs an inductively heated hot wall reactor as the energy source to start nanoparticle formation from a mixture of precursor vapor and oxygen. By use of a modular set of susceptor segments, it is especially possible to change solely the residence time of the gas mixture while keeping all other process parameters (temperature, gas flow, pressure) constant. Corresponding time–temperature profiles are supported by computational fluid dynamics simulations. The operation of the system is demonstrated for two example studies: tin oxide nanoparticle formation studied by small angle x-ray scattering and iron oxide nanoparticle formation by x-ray absorption spectroscopy.

APA, Harvard, Vancouver, ISO, and other styles

31

Dehghan Hamedan, Ali, and Mohammad Shahmiri. "A new model for the solidification of metal matrix nanocomposites: Wet cluster engulfment of nanoparticles by the solidification front." Journal of Composite Materials 51, no. 20 (April 4, 2017): 2913–32. http://dx.doi.org/10.1177/0021998317701557.

Full text

Abstract:

In this article, a new mechanism so-called wet cluster engulfment and the related formula were proposed to predict the critical solidification velocity for nanoparticles engulfment by a solidification front. According to the mechanism, the most important issue in the engulfing of the nanoparticles is the aggregation of nanoparticles, i.e. the formation of wet clusters in front of solidifying phase. In fact, local clustering of nanoparticles created highly viscous zones in the vicinity of the solidification front so that the nanoparticles and the liquid-filled spaces between them move as a unified mass. Thus, the van der Waals and drag forces between a nanoparticles cluster and the solidification front were calculated analytically. The new formulae were derived for the critical solidification velocity and critical diameter of the clusters as a function of the melt viscosity, the nanoparticle size, the cluster size, and the nanoparticle volume concentration inside the cluster. The theoretical results showed that the new model predicted more accurate values for the critical velocity than the earlier models. The proposed model can explain the formation of nanoparticle-rich zones and zones with a low concentration of nanoparticles in the microstructure of the nanocomposites produced via casting.

APA, Harvard, Vancouver, ISO, and other styles

32

Ishak, Mohamad Nizam, K. A. Yaacob, and Ahmad Fauzi Mohd Noor. "The Effect of Ligands on CdSe Nanoparticle Films Deposited by EPD." Advanced Materials Research 1087 (February 2015): 304–8. http://dx.doi.org/10.4028/www.scientific.net/amr.1087.304.

Full text

Abstract:

Nanoparticle from group II-IV semiconductor nanoparticles is widely studied for solar cells. The ability to modify the surface of nanoparticle is significant to successful use in various applications. In this research, mercaptoundecionic acid (MUA) and trioctyl phosphine oxide (TOPO) were used as ligand for cadmium selenide (CdSe) nanoparticles. The wavelength shift to a shorter value observed due to decreasing size of CdSe nanoparticle after ligand exchange from TOPO to MUA. The electrophoretic deposition methods (EPD) have being employed to deposite CdSe nanoparticles films on fluorine doped tin oxide (FTO). The deposition voltages used are between 100 - 400 V for 15 minutes. From SEM results show the formation layer of CdSe nanoparticles capped with MUA is strong and porous as compared to CdSe nanoparticle capped with TOPO. MUA capped CdSe shows better cell efficiency compared to TOPO capped CdSe which is 0.1735 %.

APA, Harvard, Vancouver, ISO, and other styles

33

LIAO, YUANBAO, JIAJIA WU, LING XU, FEI YANG, WENQING LIU, JUN XU, LIANGCAI WU, ZHONGYUAN MA, and KUNJI CHEN. "FORMATION, STRUCTURE AND PROPERTIES OF HIGHLY ORDERED SUB-30-nm PHASE CHANGE MATERIALS (GST) NANOPARTICLE ARRAYS." Surface Review and Letters 17, no. 04 (August 2010): 405–10. http://dx.doi.org/10.1142/s0218625x10014259.

Full text

Abstract:

Chalcogenide phase change material Ge1Sb2Te4 (GST) nanoparticle arrays with long-range-order were fabricated by using a monolayer of self-assembled polystyrene (PS) spheres as mask. The morphology of nanoparticle arrays can be controlled via changing RIE processing conditions. Images of atomic force microscopy (AFM) and scanning electron microscopy (SEM) show that highly uniform GST nanoparticle arrays with particle density around 109 cm-2 were formed. The sizes of nanoparticles can be reduced to a tiny diameter in the range of 30–40 nm (top diameter). The GST nanoparticle arrays exhibit a prominent peak near 580 nm in reflectance spectra, which indicates that they possess a photonic band gap. These results confirm that GST nanoparticle arrays have a 2D periodicity and long-range order. The method of nanosphere lithograph may apply to manufacturing of high density memory devices based on phase change-based memory materials.

APA, Harvard, Vancouver, ISO, and other styles

34

Sutthavas, Pichaporn, Matthias Schumacher, Kai Zheng, Pamela Habibović, Aldo Roberto Boccaccini, and Sabine van Rijt. "Zn-Loaded and Calcium Phosphate-Coated Degradable Silica Nanoparticles Can Effectively Promote Osteogenesis in Human Mesenchymal Stem Cells." Nanomaterials 12, no. 17 (August 24, 2022): 2918. http://dx.doi.org/10.3390/nano12172918.

Full text

Abstract:

Nanoparticles such as mesoporous bioactive glasses (MBGs) and mesoporous silica nanoparticles (MSN) are promising for use in bone regeneration applications due to their inherent bioactivity. Doping silica nanoparticles with bioinorganic ions could further enhance their biological performance. For example, zinc (Zn) is often used as an additive because it plays an important role in bone formation and development. Local delivery and dose control are important aspects of its therapeutic application. In this work, we investigated how Zn incorporation in MSN and MBG nanoparticles impacts their ability to promote human mesenchymal stem cell (hMSC) osteogenesis and mineralization in vitro. Zn ions were incorporated in three different ways; within the matrix, on the surface or in the mesopores. The nanoparticles were further coated with a calcium phosphate (CaP) layer to allow pH-responsive delivery of the ions. We demonstrate that the Zn incorporation amount and ion release profile affect the nanoparticle’s ability to stimulate osteogenesis in hMSCs. Specifically, we show that the nanoparticles that contain rapid Zn release profiles and a degradable silica matrix were most effective in inducing hMSC differentiation. Moreover, cells cultured in the presence of nanoparticle-containing media resulted in the highest induction of alkaline phosphate (ALP) activity, followed by culturing hMSC on nanoparticles immobilized on the surface as films. Exposure to nanoparticle-conditioned media did not increase ALP activity in hMSCs. In summary, Zn incorporation mode and nanoparticle application play an important role in determining the bioactivity of ion-doped silica nanoparticles.

APA, Harvard, Vancouver, ISO, and other styles

35

Song, Mun Seop, Chong Seung Yoon, and Young Ho Kim. "Cu Oxide Nanoparticle Formation: Effects of Curing Time." Materials Science Forum 475-479 (January 2005): 3555–58. http://dx.doi.org/10.4028/www.scientific.net/msf.475-479.3555.

Full text

Abstract:

Cu oxide nanoparticles were formed by reacting with Polyamic acid (PAA) with Cu during imidization. In this paper, we investigated the effect of holding time during curing on the Cu oxide nanoparticle formation. Cu thin films were deposited on SiO2/Si substrates by thermal evaporation. Polyamic acid was then spin-coated on the Cu thin film. The polyamic acid films were soft-baked at 135°C for 30 minutes and thermally cured at 350°C with various holding time in a nitrogen atmosphere. The size of the Cu2O nanoparticles formed in the polyimide (PI) matrix increased as the holding time increased. The size and distribution of Cu oxide particles were characterized using Transmission Electron Microscope (TEM). The degree of imidization of PI also increased proportional to the increase in holding time. The degree of PI imidization was analyzed by Infrared (IR) spectroscopy. Very uniform Cu2O particles less than 5 nm in size with particle density greater than 2×1012/cm2 were fabricated by controlling the holding time during curing.

APA, Harvard, Vancouver, ISO, and other styles

36

Miyakawa, Masato, Norihito Hiyoshi, Masateru Nishioka, Hidekazu Koda, Koichi Sato, Akira Miyazawa, and Toshishige M. Suzuki. "Continuous syntheses of Pd@Pt and Cu@Ag core–shell nanoparticles using microwave-assisted core particle formation coupled with galvanic metal displacement." Nanoscale 6, no. 15 (2014): 8720–25. http://dx.doi.org/10.1039/c4nr00118d.

Full text

APA, Harvard, Vancouver, ISO, and other styles

37

Biehler, Erik, Qui Quach, Clay Huff, and Tarek M. Abdel-Fattah. "Organo-Nanocups Assist the Formation of Ultra-Small Palladium Nanoparticle Catalysts for Hydrogen Evolution Reaction." Materials 15, no. 7 (April 6, 2022): 2692. http://dx.doi.org/10.3390/ma15072692.

Full text

Abstract:

Ultra-small palladium nanoparticles were synthesized and applied as catalysts for a hydrogen evolution reaction. The palladium metal precursor was produced via beta-cyclodextrin as organo-nanocup (ONC) capping agent to produce ultra-small nanoparticles used in this study. The produced ~3 nm nanoparticle catalyst was then characterized via X-ray diffraction (XRD), transmission electron microscopy (TEM), ultraviolet-visible spectroscopy (UV-Vis), and Fourier transform infrared spectroscopy (FTIR) to confirm the successful synthesis of ~3 nm palladium nanoparticles. The nanoparticles’ catalytic ability was explored via the hydrolysis reaction of sodium borohydride. The palladium nanoparticle catalyst performed best at 303 K at a pH of 7 with 925 μmol of sodium borohydride having an H2 generation rate of 1.431 mL min−1 mLcat−1. The activation energy of the palladium catalyst was calculated to be 58.9 kJ/mol.

APA, Harvard, Vancouver, ISO, and other styles

38

Park, Hoon, H. S. Jie, Kyou Hyun Kim, Jae Pyong Ahn, and Jong Ku Park. "In-Situ TEM Observation on Phase Formation of TiO₂ Nanoparticle Synthesized by Flame Method." Materials Science Forum 534-536 (January 2007): 81–84. http://dx.doi.org/10.4028/www.scientific.net/msf.534-536.81.

Full text

Abstract:

TiO2 nanoparticle was synthesized by the flame method using a metal organic precursor of titanium tetraisopropoxide (TTIP, Ti(OC3H7)4), which was controlled by varying the ratio and flow rate of gas mixtures consisting of oxygen (oxidizer), methane (fuel) and nitrogen (carrier gas). The morphology and the size distribution of nanoparticles were observed with TEM and FESEM, and the phase evolution was analyzed by XRD measurement using a monochromator. The crystalline phases of TiO2 nanoparticle depended strongly on the temperature distribution in the flame, whereas the morphology was not sensitive. During the flame synthesis of TiO2 nanoparticle, anatase TiO2 nanoparticle was predominantly synthesized at the high flame temperature and rapid flame cooling condition. The low flame temperature and long flame length enabled to form almost rutile TiO2 nanoparticle (>95%). The anatase nanoparticle was formed by a homogeneous nucleation and has finally kept the anatase phase without the phase transformation any more in the flame. However, the rutile TiO2 nanoparticle was not formed directly and homogeneously in flame, and was manufactured by the phase transformation such as amorphousanataserutile. It was proved that the rutile phase was nucleated heterogeneously from the amorphous or anatase particles.

APA, Harvard, Vancouver, ISO, and other styles

39

Miyakawa, Masato, Norihito Hiyoshi, Hidekazu Koda, Kenichi Watanabe, Hideki Kunigami, Hiroshi Kunigami, Akira Miyazawa, and Masateru Nishioka. "Continuous syntheses of carbon-supported Pd and Pd@Pt core–shell nanoparticles using a flow-type single-mode microwave reactor." RSC Advances 10, no. 11 (2020): 6571–75. http://dx.doi.org/10.1039/c9ra10140c.

Full text

APA, Harvard, Vancouver, ISO, and other styles

40

Morga, M., Z. Adamczyk, and D. Kosior. "Silica nanoparticle monolayers on a macroion modified surface: formation mechanism and stability." Physical Chemistry Chemical Physics 19, no. 34 (2017): 22721–32. http://dx.doi.org/10.1039/c7cp03876c.

Full text

Abstract:

Even though silica nanoparticles and their monolayers find a broad field of applications, only a few studies providing a quantitative description of silica nanoparticle deposition at solid/liquid interfaces have been reported in the literature.

APA, Harvard, Vancouver, ISO, and other styles

41

Lee, Jae Hoon, Shin Young Park, In-Gyu Choi, and Joon Weon Choi. "Investigation of Molecular Size Effect on the Formation of Lignin Nanoparticles by Nanoprecipitation." Applied Sciences 10, no. 14 (July 17, 2020): 4910. http://dx.doi.org/10.3390/app10144910.

Full text

Abstract:

In recent years, several studies focused on the synthesis of lignin-based nanoparticle in aqueous solution and its potential applications of the drug carrier were investigated. In this study, soda lignin (SL) nanoparticles (i.d. 128–560 nm) were synthesized by the nanoprecipitation process at three different concentrations (1, 2, and 4 mg/mL THF) with various molecular sizes of soda lignin (NP-F1, NP-F2, and NP-F3) obtained from sequential solvent extraction. The average molecular weights of SL, F1, F2, F3, F4, and F5 were 3130, 1190, 2550, 3680, 5310, and 14,650, respectively. The average size of the spherical lignin nanoparticle was a minimum of 128 nm for NP-C1 and the size increased up to 560 nm with increasing concentration. Particle surface charge increased with increasing concentration from −26 mV for NP-C1 to −38 mV for NP-C4. Contrary to expected general trends in polymeric nanoparticles, there was no remarkable change or trend with increasing lignin molecular weight since chemical structures of each lignin fraction are also remarkably different. Further studies to learn correlation between properties of lignin nanoparticle and its additional details regarding the chemical structures is needed.

APA, Harvard, Vancouver, ISO, and other styles

42

Yan, Jiwang, Zhiyu Zhang, and Tsunemoto Kuriyagawa. "Effect of Nanoparticle Lubrication in Diamond Turning of Reaction-Bonded SiC." International Journal of Automation Technology 5, no. 3 (May 5, 2011): 307–12. http://dx.doi.org/10.20965/ijat.2011.p0307.

Full text

Abstract:

Lubrication is a key issue in diamond turning of hard materials. This paper explores the feasibility of nanoparticle lubrication in diamond turning of reaction-bonded SiC. Four types of nanoparticles were dispersed in lubricating grease and applied to a workpiece surface. Results showed that the type and concentration of dispersed nanoparticles significantly affected lubricating performance. Grease containing 10% Cu nanoparticles produced the highest surface quality and the lowest tool wear. Lubrication is discussed in terms of nanoparticle-induced solid lubricating film formation at the tool-workpiece interface.

APA, Harvard, Vancouver, ISO, and other styles

43

Pászti, Zoltán, Zsolt E. Horváth, Gábor Pető, Albert Karacs, and L. Guczi. "Nanoparticle Formation during Laser Ablation." Solid State Phenomena 56 (August 1997): 207–12. http://dx.doi.org/10.4028/www.scientific.net/ssp.56.207.

Full text

APA, Harvard, Vancouver, ISO, and other styles

44

Tian, Fei, Lili Cai, Chao Liu, and Jiashu Sun. "Microfluidic technologies for nanoparticle formation." Lab on a Chip 22, no. 3 (2022): 512–29. http://dx.doi.org/10.1039/d1lc00812a.

Full text

APA, Harvard, Vancouver, ISO, and other styles

45

Olenin, A. Yu. "Mechanisms of metal nanoparticle formation." Nanotechnologies in Russia 7, no. 5-6 (May 2012): 238–42. http://dx.doi.org/10.1134/s1995078012030123.

Full text

APA, Harvard, Vancouver, ISO, and other styles

46

Matsunaga, Tadashi, and Haruko Takeyama. "Biomagnetic nanoparticle formation and application." Supramolecular Science 5, no. 3-4 (July 1998): 391–94. http://dx.doi.org/10.1016/s0968-5677(98)00037-6.

Full text

APA, Harvard, Vancouver, ISO, and other styles

47

Grand, J., S. R. Ferreira, V. de Waele, S. Mintova, and T. M. Nenoff. "Nanoparticle Alloy Formation by Radiolysis." Journal of Physical Chemistry C 122, no. 24 (May 25, 2018): 12573–88. http://dx.doi.org/10.1021/acs.jpcc.8b01878.

Full text

APA, Harvard, Vancouver, ISO, and other styles

48

Perrey, C. R., and C. B. Carter. "Insights into nanoparticle formation mechanisms." Journal of Materials Science 41, no. 9 (April 17, 2006): 2711–22. http://dx.doi.org/10.1007/s10853-006-7874-z.

Full text

APA, Harvard, Vancouver, ISO, and other styles

49

Scaiano, Juan C., José C. Netto-Ferreira, Emilio Alarcon, Paul Billone, Carlos J. Bueno Alejo, Charles-Oneil L. Crites, Matthew Decan, et al. "Tuning plasmon transitions and their applications in organic photochemistry." Pure and Applied Chemistry 83, no. 4 (March 14, 2011): 913–30. http://dx.doi.org/10.1351/pac-con-11-01-09.

Full text

Abstract:

The ketone-photoinduced formation of Au, Ag, and Cu nanoparticles from their corresponding ions in solution has been carried out using benzoin photoinitiators. Ketones are good photosensitizers for nanoparticle synthesis not because of the energy they can absorb or deliver, but rather because of the reducing free radicals they can generate. Efficient photochemical nanoparticle generation thus requires a careful selection of substrates and experimental conditions such that free radical generation occurs with high quantum efficiency, where metal ion precursors do not inhibit radical formation. A key consideration to achieve nanoparticle synthesis with short exposure times is to minimize excited-state quenching by metal ions. Applications of nanostructures in catalysis require control of the nanoparticle characteristics, such as dimension, morphology, and surface properties. Part of this article describes the strategies to modify photochemically prepared particles. Finally, we illustrate some of the nanoparticle applications that interest us, with some emphasis on plasmon-mediated processes.

APA, Harvard, Vancouver, ISO, and other styles

50

Lee, Jae Hoon, Tae Min Kim, In-Gyu Choi, and Joon Weon Choi. "Phenolic Hydroxyl Groups in the Lignin Polymer Affect the Formation of Lignin Nanoparticles." Nanomaterials 11, no. 7 (July 9, 2021): 1790. http://dx.doi.org/10.3390/nano11071790.

Full text

Abstract:

Alkaline soda lignin (AL) was sequentially fractionated into six fractions of different molecular size by means of solvent extraction and their phenolic hydroxyl groups were chemoselectively methylated to determine their effect on nanoparticle formation of lignin polymers. The effect of the lignin structure on the physical properties of nanoparticles was also clarified in this study. Nanoparticles were obtained from neat alkaline soda lignin (ALNP), solvent-extracted fractions (FALNPs, i.d. 414–1214 nm), and methylated lignins (MALNPs, i.d. 516–721 nm) via the nanoprecipitation method. Specifically, the size properties of MALNPs showed a high negative correlation (R2 = 0.95) with the phenolic hydroxyl group amount. This indicates that the phenolic hydroxyl groups in lignin could be influenced on the nucleation or condensation during the nanoprecipitation process. Lignin nanoparticles exhibited high colloidal stability, and most of them also showed good in vitro cell viability. This study presents a possible way to control nanoparticle size by blocking specific functional groups and decreasing the interaction between hydroxyl groups of lignin.

APA, Harvard, Vancouver, ISO, and other styles

Journal articles on the topic 'Nanoparticle formation'

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles