scholarly journals Identification of the key steps in the self-assembly of homogeneous gold metal nanoparticles produced using inverse micelles

2020 ◽  
Vol 22 (34) ◽  
pp. 18824-18834 ◽  
Author(s):  
Donato Decarolis ◽  
Yaroslav Odarchenko ◽  
Jennifer J. Herbert ◽  
Chengwu Qiu ◽  
Alessandro Longo ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Metal Nanoparticles ◽  
Self Assembly ◽  
The Self ◽  
Au Nps ◽  
X Ray ◽  
Inverse Micelles ◽  
Vis Spectroscopy ◽  
Key Steps ◽  
Gold Metal

The self-assembly of gold nanoparticles (Au NPs) using polymer-encapsulated inverse micelles was studied using a set of advanced X-ray techniques (i.e. XAFS, SAXS) in addition to DLS, UV-vis spectroscopy and TEM.

scholarly journals The di(thiourea)gold(I) complex [Au{S=C(NH2)2}2][SO3Me] as a precursor for the convenient preparation of gold nanoparticles

2020 ◽  
Vol 75 (3) ◽  
pp. 239-249
Author(s):  
Alexander Kossmann ◽  
Rayko Ehnert ◽  
Andrea Preuß ◽  
Natalia Rüffer ◽  
Marcus Korb ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Methanesulfonic Acid ◽  
X Ray Diffraction ◽  
Au Nps ◽  
X Ray ◽  
Vis Spectroscopy ◽  
Decomposition Behavior ◽  
Spectroscopy Studies ◽  
Convenient Preparation ◽  
Gold Metal

AbstractThe synthesis of [Au{S=C(NH2)2}2][SO3Me] (1) (a) by the anodic oxidation of gold metal in an anolyte of thiourea and methansulfonic acid and (b) by the reaction of Au(OH)3 with an aqueous solution of methanesulfonic acid in the presence of thiourea is reported. The structure of 1 in the solid state has been determined by single-crystal X-ray diffraction showing a linear S–Au–S unit with the thiourea ligands in a leaflet structure folded by 113.2(3)°. The cation of complex 1 is a dimer, based on short S · · · C interactions between two adjacent mononuclear cations. The thermal decomposition behavior of 1 was studied by TG and TG-MS confirming that it decomposes under inert gas or oxygen atmosphere in four steps in the temperature range of 200–650°C. Initial decomposition starts with the release and fragmentation of one of the thiourea ligands, followed by the anion degradation. Powder X-ray diffraction studies specified the formation of gold metal. Based on this observation, complex 1 was used as precursor for the formation of gold nanoparticles (Au NPs) in 1-hexadecylamine (c = 4.0 mol L−1) at T = 330°C without any addition of reducing agents. TEM, electron diffraction, and UV/Vis spectroscopy studies were carried out. Au NPs of size 15 ± 4 nm were formed, showing the characteristic surface plasmon resonance at 528 nm.

scholarly journals Single-step assembly of gold nanoparticles into plasmonic colloidosomes at the interface of oleic acid nanodroplets

2021 ◽  
Vol 3 (1) ◽  
pp. 198-205
Author(s):  
José M. López-de-Luzuriaga ◽  
Miguel Monge ◽  
Javier Quintana ◽  
María Rodríguez-Castillo
Keyword(s):  
Gold Nanoparticles ◽  
Oleic Acid ◽  
Self Assembly ◽  
Single Step ◽  
The Self ◽  
Au Nps ◽  
Spherical Gold Nanoparticles

Plasmonic gold colloidosomes (Au CSs) of sub-200 nm size are formed by the self-assembly of spherical gold nanoparticles (Au NPs) of ca. 4 nm size at the interface of oleic acid (OA) nanodroplets formed in n-hexane.

Synthesis and aggregation properties of boron-dipyrromethene dyes conjugated with guanine units

2018 ◽  
Vol 22 (09n10) ◽  
pp. 944-952 ◽  
Author(s):  
Fen Li ◽  
Yongjie Zhang ◽  
Lina Zhou ◽  
Xin Zhang ◽  
Zhijian Chen
Keyword(s):  
Self Assembly ◽  
Solvent Polarity ◽  
The Self ◽  
X Ray ◽  
X Ray Crystallography ◽  
H Nmr ◽  
Nmr Study ◽  
Vis Spectroscopy ◽  
G Quadruplex ◽  
Boron Dipyrromethene

Two boron-dipyrromethene dyes bearing a conjugated guanine unit (G-BODIPYs) 1 and 2 were synthesized and fully characterized. The self-assembly properties of these dyes were investigated by X-ray crystallography, [Formula: see text]H NMR and UV-vis spectroscopy. As revealed by X-ray crystal structure studies, G-BODIPY 1 self-assembled into ribbon-like structures due to the intermolecular hydrogen bonding and [Formula: see text]–[Formula: see text] stacking interaction. Concentration-dependent [Formula: see text]H NMR experiments confirmed the formation of hydrogen bonds of the guanine units in solution for both dye 1 and 2. In the presence of K[Formula: see text], the characteristic signals for the formation of cyclic G-quadruplex structures were observed in the [Formula: see text]H NMR study. Aggregation of G-BODIPY dyes was further monitored by UV-vis absorption spectroscopy by varying the solvent polarity and temperature. H-type aggregates of dye 1, which was characterized by a new hypsochromically shifted absorption band with [Formula: see text] 461 nm, was obtained. In the presence of K[Formula: see text], the enhancement of stability was observed for the H-aggregates of dye 1.

scholarly journals Green Synthesis of Gold Nanoparticles Using Upland Cress and Their Biochemical Characterization and Assessment

Nanomaterials ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 28
Author(s):  
Noah Hutchinson ◽  
Yuelin Wu ◽  
Yale Wang ◽  
Muskan Kanungo ◽  
Anna DeBruine ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Zeta Potential ◽  
Green Synthesis ◽  
Synthesis Process ◽  
Gold Content ◽  
Face Centered Cubic ◽  
X Ray Diffraction ◽  
Au Nps ◽  
X Ray ◽  
Vis Spectroscopy

This research focuses on the plant-mediated green synthesis process to produce gold nanoparticles (Au NPs) using upland cress (Barbarea verna), as various biomolecules within the upland cress act as both reducing and capping agents. The synthesized gold nanoparticles were thoroughly characterized using UV-vis spectroscopy, surface charge (zeta potential) analysis, scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX), atomic force microscopy (AFM), attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), and X-ray diffraction (XRD). The results indicated the synthesized Au NPs are spherical and well-dispersed with an average diameter ~11 nm and a characteristic absorbance peak at ~529 nm. EDX results showed an 11.13% gold content. Colloidal Au NP stability was confirmed with a zeta potential (ζ) value of −36.8 mV. X-ray diffraction analysis verified the production of crystalline face-centered cubic gold. Moreover, the antimicrobial activity of the Au NPs was evaluated using Gram-negative Escherichiacoli and Gram-positive Bacillus megaterium. Results demonstrated concentration-dependent antimicrobial properties. Lastly, applications of the Au NPs in catalysis and biomedicine were evaluated. The catalytic activity of Au NPs was demonstrated through the conversion of 4-nitrophenol to 4-aminophenol which followed first-order kinetics. Cellular uptake and cytotoxicity were evaluated using both BMSCs (stem) and HeLa (cancer) cells and the results were cell type dependent. The synthesized Au NPs show great potential for various applications such as catalysis, pharmaceutics, and biomedicine.

Synthesis and Characterization of Gold Nanoparticles Grafted on Nanoporous Anodic Aluminum Oxide (AAO) Membrane

2015 ◽  
Vol 752-753 ◽  
pp. 77-80 ◽  
Author(s):  
Hanani Yazid ◽  
Nek Zamzila Nekhia ◽  
Rohana Adnan ◽  
Abdul Mutalib Md Jani
Keyword(s):  
Gold Nanoparticles ◽  
Anodic Aluminum Oxide ◽  
Diffuse Reflectance ◽  
Au Nps ◽  
X Ray ◽  
Anodic Aluminum ◽  
Vis Spectroscopy ◽  
Anionic Exchange ◽  
Nanoporous Anodic Aluminum Oxide

Gold nanoparticles (Au NPs) supported on nanoporous anodic aluminium oxide (AAO) membrane has been successfully prepared by direct anionic exchange for further application in catalysis. The nanoporous AAO membrane is immersed in HAuCl4 solution at different pH to achieve gold nanoparticles grafted on AAO (Au-AAO). It was found that the pH of the HAuCl4 solution played an important role for controlling the size of Au NPs as well as the amount of Au depositing on the surface of AAO membrane. The prepared Au-AAO membranes were characterized by diffuse reflectance UV-Vis spectroscopy, high-resolution scanning electron microscopy (SEM) and energy dispersive x-ray (EDX) spectroscopy.

scholarly journals Gold nanoparticle fortified bamboo biochar Nanocomposite

2021 ◽  
Author(s):  
Aditya lawerence Toppo ◽  
Satya Eswari Jujjavarapu
Keyword(s):  
Gold Nanoparticles ◽  
Gold Nanoparticle ◽  
Low Cost ◽  
Analytical Techniques ◽  
Organic Matrix ◽  
Chloride Salt ◽  
Biological Origin ◽  
Au Nps ◽  
X Ray ◽  
Vis Spectroscopy

Abstract Gold nanoparticles due to their specific properties and function have found uses in the field of engineering to medical sciences. The Gold nanoparticles are always used in conjugation with other chemicals, metals, proteins, and other organic materials. The addition of other conjugates enhances the properties of Gold nanoparticles. As the insertion of metal nanoparticles into an organic matrix effectively increases the specific surface area of such materials, thereby enhancing the desired properties of the material. The term nanocomposite(NCs) is used for material containing an inorganic moiety, with at least one dimension in a nanometre range of 1–100 nm(nanoparticles ) and other materials like metal, ceramics, and polymers. The term “Bionanocomposite" (BNCs)has been assigned to nanocomposites containing a component of biological origin in the mixture. In this work, Bamboo (Bambusa bambos) was used as the organic matrix for the preparation of gold nanoparticle biochar (Au-NPs/BC) nanocomposite. The one-step synthesis approach was used for the treatment of Bamboo with Auric Chloride Salt at room temperature. In addition to the above process, the bamboo was also pyrolyzed at low temperature after treatment, which helped further to reduce the overall cost of the method. This made the method of preparation of the nanocomposite low cost and eco-friendly. Various analytical techniques such as Fourier transform infrared (FT-IR), X‐ray diffraction (XRD), Scanning electron microscopy (SEM), Energy dispersive X‐ray spectroscopy (EDS), and UV–Vis spectroscopy methods were used for the characterization of the synthesized nanocomposite. This nanocomposite was used for the preparation of electrodes and its electrical conductivity was tested. In this method, the nanocomposite was prepared in a good amount via a very simple methodology. The characterization revealed the presence of gold in the nanocomposite, which confirms that this method can be used for the preparation of the (Au-NPs/BC) nanocomposite.

scholarly journals Synthesis and biological activities of alcohol extract of black cumin seeds (Bunium persicum)-based gold nanoparticles and their catalytic applications

2021 ◽  
Vol 10 (1) ◽  
pp. 440-455
Author(s):  
Omar Bahattab ◽  
Ibrahim Khan ◽  
Sami Bawazeer ◽  
Abdur Rauf ◽  
Muhammad Nasimullah Qureshi ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Biological Activities ◽  
Seed Extract ◽  
Alcohol Extract ◽  
Au Nps ◽  
X Ray ◽  
Black Cumin ◽  
Bunium Persicum ◽  
Vis Spectroscopy ◽  
Pharmaceutical Industries

Abstract Fast, simple, and environmentally friendly gold nanoparticles (Au-NPs) capped and stabilized with black cumin (Bunium persicum) seed alcohol extract are reported. The aqueous gold ions (Au3+) were treated with B. persicum (BP) seed extract, which resulted in a rapid color change to red, indicating the synthesis of Au-NPs. UV-Vis spectroscopy, FTIR, SEM, energy dispersive X-ray (EDX), and X-ray diffraction (XRD) techniques were used to further characterize the Au-NPs. Its stability was assessed against various pH levels and sodium chloride levels (NaCl), different salts of same concentration as well as at a range of temperature (30–100°C). The UV-Vis spectrum in the Au-NPs produced a 540 nm plasmon surface resonance, and a 25–50 nm range of particulates was shown in the SEM analysis. In addition, the FTIR spectra confirmed the inclusion in the capping and decrease of Au-NPs of amines, amide groups, and alcohols. The EDX analysis confirmed the presence of element Au. Furthermore, Au-NPs were tested for enzyme inhibition and antibacterial and antifungal activities and showed remarkable response. These findings have concluded that BP seed extract is an effective bio-reductant of gold nanoparticle synthesis, which can be further applied in different biomedical and pharmaceutical industries.

The Evaluation of TiTe2 as a Diffusion Barrier in the Formation of Low Thermal Conductivity Nanolaminates with Bi2Te3 and Sb2Te3

2010 ◽  
Vol 74 ◽  
pp. 38-47
Author(s):  
Clay Mortensen ◽  
Paul Zschack ◽  
David C. Johnson
Keyword(s):  
Thermal Conductivity ◽  
Diffusion Barrier ◽  
Self Assembly ◽  
Low Temperatures ◽  
Annealing Temperature ◽  
The Self ◽  
High Angle ◽  
X Ray Diffraction ◽  
Amorphous Precursor ◽  
X Ray

The evolution of designed [(Ti-Te)]x[(Sb-Te)]y, [(Bi-Te)]x[(Sb-Te)]y, [(Ti-Te)]w[(Bi-Te)]x[(Sb-Te)]y and [(Ti-Te)]w[(Bi-Te)]x[(Ti-Te)]y[(Sb-Te)]z precursors were followed as a function of annealing temperature and time using both low and high angle x-ray diffraction techniques to probe the self assembly into nanolaminate materials. The [(Bi-Te)]x[(Sb-Te)]y precursors were found to interdiffuse at low temperatures to form a (BixSb1-x)2Te3 alloy. The [(Ti-Te)]x[(Bi-Te)]y and [(Ti-Te)]x[(Sb-Te)]y precursors formed ordered nanolaminates [{(TiTe2)}1.35]x[Bi2Te3]y and [{(TiTe2)}1.35]x[Sb2Te3]y respectively. The [(Ti-Te)]w[(Bi-Te)]x[(Sb-Te)]x precursors formed [{(TiTe2)}1.35]w[(Bi0.5Sb0.5)2Te3]2x nanolaminates on annealing, as the bismuth and antimony layers interdiffused. Over the range of TiTe2 thicknesses used in [(Ti-Te)]w[(Bi-Te)]x[(Ti-Te)]y[(Sb-Te)]z precursors, Bi and Sb were found to interdiffuse through the 2-4 nm thick Ti-Te layers, resulting in the formation of (BixSb1-x)2Te3 alloy layers as part of the final nanolaminated products. When the Bi-Te and Sb-Te thicknesses were equal in the amorphous precursors, symmetric [{(TiTe2)}1.35]m[(Bi0.5Sb0.5)2Te3]n nanolamiantes were formed. When the thicknesses of Bi-Te and Sb-Te layers were not equal in the amorphous precursor, asymmetric [(TiTe2)1.35]m[(BixSb1-x)2Te3]n[(TiTe2)1.35]m[(BixSb1-x)2Te3]p nanolaminates were formed. These results imply that to form (A)w(B)x(C)y nanolaminates using designed layered precursors all three components must be immiscible. To form (A)x(B)y(A)x(C)z nanolaminates, the components must be immiscible or the precursor to the A component and the A component itself must be an effective interdiffusion barrier preventing B and C from mixing.

scholarly journals Effects of Different Surfactant Charges on the Formation of Gold Nanoparticles by the LASiS Method

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2937
Author(s):  
Muhammad Zulfajri ◽  
Wei-Jie Huang ◽  
Genin-Gary Huang ◽  
Hui-Fen Chen
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Gold Nanoparticles ◽  
Laser System ◽  
Synthesis Process ◽  
Au Nps ◽  
Laser Fluences ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
532 Nm

The laser ablation synthesis in solution (LASiS) method has been widely utilized due to its significant prospects in laser microprocessing of nanomaterials. In this study, the LASiS method with the addition of different surfactant charges (cationic CTAB, nonionic TX-100, and anionic SDS) was used to produce Au NPs. An Nd:YAG laser system at 532 nm excitation with some synthetic parameters, including different laser fluences, ablation times, and surfactant concentrations was performed. The obtained Au NPs were characterized by UV-Vis spectroscopy, transmission electron microscopy, and zeta potential analyzer. The Au NPs exhibited the maximum absorption peak at around 520 nm for all samples. The color of Au NPs was changed from red to reddish by increasing the laser fluence. The surfactant charges also played different roles in the Au NPs’ growth during the synthesis process. The average sizes of Au NPs were found to be 8.5 nm, 5.5 nm, and 15.5 nm with the medium containing CTAB, TX-100, and SDS, respectively. Besides, the different surfactant charges induced different performances to protect Au NPs from agglomeration. Overall, the SDS and CTAB surfactants exhibited higher stability of the Au NPs compared to the Au NPs with TX-100 surfactant.

scholarly journals Cylindrical Micelles by the Self-Assembly of Crystalline-b-Coil Polyphosphazene-b-P2VP Block Copolymers. Stabilization of Gold Nanoparticles

Molecules ◽  
2019 ◽  
Vol 24 (9) ◽  
pp. 1772 ◽  
Author(s):  
Maria de los Angeles Cortes ◽  
Raquel de la Campa ◽  
Maria Luisa Valenzuela ◽  
Carlos Díaz ◽  
Gabino A. Carriedo ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Block Copolymers ◽  
Self Assembly ◽  
Cationic Polymerization ◽  
The Self ◽  
The Novel ◽  
Selective Solvent ◽  
The Core ◽  
Cylindrical Micelles ◽  
Main Factor

During the last number of years a variety of crystallization-driven self-assembly (CDSA) processes based on semicrystalline block copolymers have been developed to prepare a number of different nanomorphologies in solution (micelles). We herein present a convenient synthetic methodology combining: (i) The anionic polymerization of 2-vinylpyridine initiated by organolithium functionalized phosphane initiators; (ii) the cationic polymerization of iminophosphoranes initiated by –PR2Cl2; and (iii) a macromolecular nucleophilic substitution step, to prepare the novel block copolymers poly(bistrifluoroethoxy phosphazene)-b-poly(2-vinylpyridine) (PTFEP-b-P2VP), having semicrystalline PTFEP core forming blocks. The self-assembly of these materials in mixtures of THF (tetrahydrofuran) and 2-propanol (selective solvent to P2VP), lead to a variety of cylindrical micelles of different lengths depending on the amount of 2-propanol added. We demonstrated that the crystallization of the PTFEP at the core of the micelles is the main factor controlling the self-assembly processes. The presence of pyridinyl moieties at the corona of the micelles was exploited to stabilize gold nanoparticles (AuNPs).

Sign in / Sign up

Export Citation Format

Share Document