Large-Scale Hierarchical Self-Assembly Structures from Gold Nanoparticles

2007 ◽  
Vol 1059 ◽  
Author(s):  
Nam-Jung Kim ◽  
Hao Li
Keyword(s):  
Self Assembly ◽  
Metallic Nanoparticles ◽  
Large Scale ◽  
Room Temperature ◽  
Solid Substrate ◽  
Ionic Surfactant ◽  
Particle Nucleation ◽  
Low Density ◽  
Density Region ◽  
Sem Image

ABSTRACTMetallic nanoparticles may form hierarchical dendrites in the presence of ionic surfactant through self-assembly upon solvent drying at room temperature. With nanoparticle density varying in the drying area on the supporting solid substrate, the morphology and relevant size of the dendrites evolve in different structures. At the region where the nanoparticle density is high, the large dendrite can develop with manifest crystal symmetry. At the low density region, many small sizes of compact crystals can be found, indicating that particle nucleation dominates over the long-range crystal growth. SEM image reveals the ordered stacking of gold nanoplates over the long dendrite branches, resembling the liquid crystal array. We present the possible physical origins to explain the various structures of the assembled dendrites during the solvent evaporation at the interface of solid and air.

Green synthesis of mixed metallic nanoparticles using room temperature self-assembly

2017 ◽  
Vol 13 (2) ◽  
pp. 4671-4677 ◽  
Author(s):  
A. M. Abdelghany ◽  
A.H. Oraby ◽  
Awatif A Hindi ◽  
Doaa M El-Nagar ◽  
Fathia S Alhakami
Keyword(s):  
Self Assembly ◽  
Metallic Nanoparticles ◽  
Room Temperature ◽  
Bimetallic Nanoparticles ◽  
Reduction Process ◽  
Nano Particles ◽  
Nano Structure ◽  
Small Shift ◽  
Molar Ratios ◽  
Vis Spectroscopy

Bimetallic nanoparticles of silver (Ag) and gold (Au) were synthesized at room temperature using Curcumin. Reduction process of silver and gold ions with different molar ratios leads to production of different nanostructures including alloys and core-shells. Produced nanoparticles were characterized simultaneously with FTIR, UV/vis. spectroscopy, transmission electron microscopy (TEM), and Energy-dispersive X-ray (EDAX). UV/vis. optical absorption spectra of as synthesized nanoparticles reveals presence of surface palsmon resonance (SPR) of both silver at (425 nm) and gold at (540 nm) with small shift and broadness of gold band after mixing with resucing and capping agent in natural extract which suggest presence of bimetallic nano structure (Au/Ag). FTIR and EDAX data approve the presence of bimetallic nano structure combined with curcumin extract. TEM micrographs shows that silver and gold can be synthesized separately in the form of nano particles using curcumin extract. Synthesis of gold nano particles in presence of silver effectively enhance and control formation of bi-metallic structure.

scholarly journals Kinked Bisamides as Efficient Supramolecular Foam Cell Nucleating Agents for Low-Density Polystyrene Foams with Homogeneous Microcellular Morphology

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1094
Author(s):  
Bastian Klose ◽  
Daniel Kremer ◽  
Merve Aksit ◽  
Kasper P. van der Zwan ◽  
Klaus Kreger ◽  
...  
Keyword(s):  
Cell Size ◽  
Self Assembly ◽  
Large Scale ◽  
Elevated Temperatures ◽  
Foam Cell ◽  
Cell Structure ◽  
Expansion Ratio ◽  
Low Density ◽  
Nucleating Agents ◽  
Foam Density

Polystyrene foams have become more and more important owing to their lightweight potential and their insulation properties. Progress in this field is expected to be realized by foams featuring a microcellular morphology. However, large-scale processing of low-density foams with a closed-cell structure and volume expansion ratio of larger than 10, exhibiting a homogenous morphology with a mean cell size of approximately 10 µm, remains challenging. Here, we report on a series of 4,4′-diphenylmethane substituted bisamides, which we refer to as kinked bisamides, acting as efficient supramolecular foam cell nucleating agents for polystyrene. Self-assembly experiments from solution showed that these bisamides form supramolecular fibrillary or ribbon-like nanoobjects. These kinked bisamides can be dissolved at elevated temperatures in a large concentration range, forming dispersed nano-objects upon cooling. Batch foaming experiments using 1.0 wt.% of a selected kinked bisamide revealed that the mean cell size can be as low as 3.5 µm. To demonstrate the applicability of kinked bisamides in a high-throughput continuous foam process, we performed foam extrusion. Using 0.5 wt.% of a kinked bisamide yielded polymer foams with a foam density of 71 kg/m3 and a homogeneous microcellular morphology with cell sizes of ≈10 µm, which is two orders of magnitude lower compared to the neat polystyrene reference foam with a comparable foam density.

scholarly journals Self-assembly of highly efficient, broadband plasmonic absorbers for solar steam generation

2016 ◽  
Vol 2 (4) ◽  
pp. e1501227 ◽  
Author(s):  
Lin Zhou ◽  
Yingling Tan ◽  
Dengxin Ji ◽  
Bin Zhu ◽  
Pei Zhang ◽  
...  
Keyword(s):  
Light Absorption ◽  
Self Assembly ◽  
Metallic Nanoparticles ◽  
Large Scale ◽  
Strong Field ◽  
Local Heating ◽  
Field Enhancement ◽  
Solar Irradiation ◽  
Steam Generation ◽  
Solar Steam Generation

The study of ideal absorbers, which can efficiently absorb light over a broad range of wavelengths, is of fundamental importance, as well as critical for many applications from solar steam generation and thermophotovoltaics to light/thermal detectors. As a result of recent advances in plasmonics, plasmonic absorbers have attracted a lot of attention. However, the performance and scalability of these absorbers, predominantly fabricated by the top-down approach, need to be further improved to enable widespread applications. We report a plasmonic absorber which can enable an average measured absorbance of ~99% across the wavelengths from 400 nm to 10 μm, the most efficient and broadband plasmonic absorber reported to date. The absorber is fabricated through self-assembly of metallic nanoparticles onto a nanoporous template by a one-step deposition process. Because of its efficient light absorption, strong field enhancement, and porous structures, which together enable not only efficient solar absorption but also significant local heating and continuous stream flow, plasmonic absorber–based solar steam generation has over 90% efficiency under solar irradiation of only 4-sun intensity (4 kW m−2). The pronounced light absorption effect coupled with the high-throughput self-assembly process could lead toward large-scale manufacturing of other nanophotonic structures and devices.

Self-Assembly of a Novel Cationic Porphyrin-Anthraquione Hybrid Investigated by Scanning Tunneling Microscopy

2010 ◽  
Vol 148-149 ◽  
pp. 1273-1276 ◽  
Author(s):  
Ai Mei Gao ◽  
Wen Li Deng ◽  
Hong Yu Chen
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Self Assembly ◽  
Large Scale ◽  
Room Temperature ◽  
Pyrolytic Graphite ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Hybrid Compound ◽  
Cationic Porphyrin ◽  
Stm Images

The self-assembly behaviour of a novel cationic porphyrin-anthraquione (Por-AQ) hybrid ([AQATMPyP]I3) on highly oriented pyrolytic graphite (HOPG) was studied at room temperature in air by scanning tunneling microscopy(STM). According to theoretical calculation, it is testified that [AQATMPyP]I3 molecule mainly exists in the closed structure. The STM results reveal the presence of large-scale domains of ordered adlayer of this hybrid compound on HOPG. The STM images show a structure constituted by parallel rows. The width of each row is approximately 2.5nm.

scholarly journals Radar observations in the vicinity of pre-noon auroral arcs

2005 ◽  
Vol 23 (5) ◽  
pp. 1785-1796 ◽  
Author(s):  
H. Nilsson ◽  
A. Kozlovsky ◽  
T. Sergienko ◽  
A. Kotikov
Keyword(s):  
Electric Fields ◽  
Formation Process ◽  
Large Scale ◽  
Average Energy ◽  
Energy Spectra ◽  
Low Density ◽  
Plasma Convection ◽  
Density Region ◽  
Incoherent Scatter ◽  
Auroral Arcs

Abstract. A combination of EISCAT incoherent scatter radar measurements, optical and magnetometer data is used to study the plasma in and around pre-noon structured precipitation and auroral arcs. Particular attention is paid to regions of comparatively low E-region density observed adjacent to arcs or structured precipitation in the EISCAT Svalbard radar field-aligned measurements. Comparison between luminosity and incoherent scatter electron density measurements shows that the low-density regions occur primarily due to the absence of diffuse precipitation rather than to a cavity formation process. Two cases of arcs and low density/luminosity regions are identified. The first is related to a strong Pc5 pulsation event, and the absence of diffuse precipitation is due to a large-scale modulation of the diffuse precipitation. In the second case the equatormost arc is on a shielding boundary and the low-density region coincides with a strong flow region just poleward of this arc. Regions of high electric field and low luminosity and conductance are observed prior to intensification of the structured precipitation in both cases. The ionospheric current is enhanced in the low conductance region, indicating that the strong electric fields do not result solely from ionospheric polarization electric fields, and thus are mainly driven by magnetospheric processes. The average energy of the precipitating electrons in the arcs and structured precipitation is, according to EISCAT measurements, 500eV and the energy spectra are similar for the pulsation and shielding cases. The average energy is thus significantly less than in the diffuse precipitation region which shows central CPS-like energy spectra. We suggest that the low ionospheric conductance of 0.7S in the low density regions is favorable for the arc formation process. This is in quantitative agreement with recent simulations of the ionospheric feedback instability. Keywords. Magnetospheric physics (Auroral phenomena; Magnetosphere-ionosphere interactions) – Ionosphere (Plasma convection)

ALCHEMI of B2-Ordered Fe50Al45Me5 alloys

1996 ◽  
Vol 54 ◽  
pp. 548-549
Author(s):  
Ian M. Anderson
Keyword(s):  
Room Temperature ◽  
Iron Aluminide ◽  
Low Density ◽  
Intermetallic Alloys ◽  
Practical Applications ◽  
Alloying Additions ◽  
Site Distribution ◽  
Good Corrosion Resistance ◽  
Room Temperature Ductility ◽  
The Matrix

B2-ordered iron aluminide intermetallic alloys exhibit a combination of attractive properties such as low density and good corrosion resistance. However, the practical applications of these alloys are limited by their poor fracture toughness and low room temperature ductility. One current strategy for overcoming these undesirable properties is to attempt to modify the basic chemistry of the materials with alloying additions. These changes in the chemistry of the material cannot be fully understood without a knowledge of the site-distribution of the alloying elements. In this paper, the site-distributions of a series of 3d-transition metal alloying additions in B2-ordered iron aluminides are studied with ALCHEMI.A series of seven alloys of stoichiometry Fe50AL45Me5, with Me = {Ti, V, Cr, Mn, Co, Ni, Cu}, were prepared with identical heating cycles. Microalloying additions of 0.2% B and 0.1% Zr were also incorporated to strengthen the grain boundaries, but these alloying additions have little influence on the matrix chemistry and are incidental to this study.

scholarly journals Self-assembly induced luminescence of Eu3+-complexes and application in bioimaging

2021 ◽  
Author(s):  
Ping-Ru Su ◽  
Tao Wang ◽  
Pan-Pan Zhou ◽  
Xiao-Xi Yang ◽  
Xiao-Xia Feng ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Rare Earth ◽  
Luminescence Intensity ◽  
Self Assembly ◽  
Room Temperature ◽  
Molecular Motion ◽  
Proof Of Concept ◽  
Room Temperature Phosphorescence ◽  
New Strategy ◽  
Size Controlled

Abstract Design and engineering of highly efficient emitting materials with assembly-induced luminescence, such as room temperature phosphorescence (RTP) and aggregation-induced emission (AIE), have stimulated extensive efforts. Here, we propose a new strategy to obtain size-controlled Eu3+-complex nanoparticles (Eu-NPs) with self-assembly induced luminescence (SAIL) characteristics without encapsulation or hybridization. Compared with previous RTP or AIE materials, the SAIL phenomena of increased luminescence intensity and lifetime in aqueous solution for the proposed Eu-NPs are due to the combined effect of self-assembly in confining the molecular motion and shielding the water quenching. As a proof of concept, we also show that this system can be further applied in bioimaging, temperature measurement and HClO sensing. The SAIL activity of the rare-earth (RE) system proposed here offers a further step forward on the roadmap for the development of RE light conversion systems and their integration in bioimaging and therapy applications.

A Novel Technique for Large-Scale Fabrication of 3D Colloidal Crystals: Suspending Self-Assembly in Water Medium (SSAM)

2021 ◽  
Author(s):  
Zhengting Zhang ◽  
Guiyun Yi ◽  
Xiaodong Wang ◽  
Peng Li ◽  
Zhuoyan Wan ◽  
...  
Keyword(s):  
Self Assembly ◽  
Large Scale ◽  
Colloidal Crystals ◽  
Water Medium ◽  
Novel Technique

In-situ construction of direct Z-scheme AgBr/α-Ag2WO4 heterojunction with promoted spatial charge migration and photocatalytic performance

2021 ◽  
Author(s):  
Xiao-Ya Zhai ◽  
Yifan Zhao ◽  
Guo-Ying Zhang ◽  
Bing-Yu Wang ◽  
Qi-Yun Mao
Keyword(s):  
Anion Exchange ◽  
Large Scale ◽  
Room Temperature ◽  
Photocatalytic Performance ◽  
Charge Migration ◽  
Time Saving ◽  
Spatial Charge ◽  
Construction Strategy ◽  
Large Scale Synthesis

In the work, a direct Z-scheme AgBr/α-Ag2WO4 heterojunction was prepared by in-situ anion exchange at room temperature. The construction strategy is energy- and time-saving for large scale synthesis. The α-Ag2WO4...

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