scholarly journals Pourous nanoparticles formation using a dendrimer template

2010 ◽  
Vol 24 (3-4) ◽  
pp. 427-431
Author(s):  
L. Bonaccorsi ◽  
D. Lombardo ◽  
A. Longo ◽  
E. Proverbio ◽  
P. Calandra
Keyword(s):  
Self Assembly ◽  
Particle Interaction ◽  
Pamam Dendrimer ◽  
The Self ◽  
Assembly Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
X Ray Scattering ◽  
Zeolite Lta ◽  
Scanning Electron

We describe the synthesis of porous spherical nanoaggregates derived by the controlled growth of zeolite LTA on a poliamidoamine (Pamam) dendrimer acting as nano-template. The presence of a strong condensed cationic Na+charge all around the dendrimers, which is responsible for the intense electrostatic inter-particle interaction potential, stimulate the condensed growth of the zeolitic phase onto the dendrimer substrate. Moreover, the screening produced by the zeolite grown on the dendrimer surface promote the entanglement process between the primary units with the formation of large porous clusters. The main features of the self-assembly process has been characterised by means of different techniques such as Small Angle X-ray Scattering (SAXS), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD) and Energy Dispersive X-ray (EDX) microprobe spectroscopy. The finding of our results may open new perspectives in the synthesis of organic–inorganic nanostructured materials based on mesoporous frameworks with new characteristics and properties.

Controlled Growth and Self-Assembly of CaCO3 Superstructures between the Organic-Water Interfaces

2010 ◽  
Vol 434-435 ◽  
pp. 597-600
Author(s):  
Xiao Hong Liang ◽  
Jun Hui Xiang ◽  
Fu Shi Zhang ◽  
Li Xing ◽  
Bo Song ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Calcium Carbonate ◽  
Self Assembly ◽  
Crystallization Behavior ◽  
Gas Diffusion ◽  
The Self ◽  
Assembly Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Scanning Electron

In this paper, the crystallization behavior of calcium carbonate between the organic-water interfaces using a slow gas-diffusion procedure is studied. The organic-water interfaces can control the crystallization of calcium carbonate to form a flower-shaped superstructure. The precipitates of calcium carbonate were identified by X-ray diffraction (XRD) and scanning electron microscopy (SEM). A possible mechanism about the self-assembly process of CaCO3 crystals has been analyzed. It is found that the morphology of CaCO3 superstructure depends on the properties of organic solvent. This paper also presents the influence of surfactant monolayer, between the biphase interfaces, on the CaCO3 superstructure. This study suggests that it is possible to control morphogenesis of calcium carbonate by a combination of a surfactant monolayer with the organic-water interfaces.

Formation of CaCO3 Superstructures in the Presence of Polyvinylpyrrolidone

2014 ◽  
Vol 912-914 ◽  
pp. 145-148
Author(s):  
Yin Xia Chen ◽  
Xian Bing Ji ◽  
Li Jing Yang
Keyword(s):  
Electron Microscopy ◽  
Calcium Carbonate ◽  
Self Assembly ◽  
Mixed Solvent ◽  
Calcium Acetate ◽  
Assembly Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Carbonate Precursor ◽  
Scanning Electron

The crystallization of calcium carbonate was conducted by the reaction of calcium acetate with urea in the presence of polyvinylpyrrolidone (PVP). The morphology and polymorphism of these products were characterized with field emission scanning electron microscopy (FESEM) and X-ray diffraction (XRD). The results showed that hierarchical CaCO3spheres were prepared in the presence of PVP. Varying the amount of PVP can prominently regulate the aggregation and self-assembly process of calcium carbonate precursor formed in mixed solvent.

Fabrication of Nanosheets and Micro-Spheres from the Self-Assembly and Polymerization of N-Octadecyltrichlorosilane

2011 ◽  
Vol 311-313 ◽  
pp. 485-488 ◽  
Author(s):  
Shuai Zhang ◽  
Qing Ping Ke ◽  
Lei Zhang ◽  
Tian Di Tang
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Self Assembly ◽  
Micelle Formation ◽  
The Self ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Hydrolysis Process ◽  
Scanning Electron

Formation of layered nanosheets and micro-spheres from a simple self-assembly and polycondensation of n-octadecylsilane (PODS) in water and toluene is demonstrated, respectively. The structure of the micro-spheres was characterized by Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM) and X-ray Diffraction (XRD). According to the TEM images, it was firstly confirmed that the micro-spheres consist of stacks of bilayered polymerized n-octadecylsilane with head-to-head arrangements. The co-effects of water and solvent were proposed to control the octadecyltrichlsilane hydrolysis process and eventually the morphology of the micro-spheres. A micelle formation mechanism for the formation of the PODS micro-spheres under the co-effects of water and solvent were firstly proposed.

scholarly journals SAXS/WAXS Investigation of Amyloid-β(16-22) Peptide Nanotubes

2021 ◽  
Vol 9 ◽  
Author(s):  
Theyencheri Narayanan ◽  
Axel Rüter ◽  
Ulf Olsson
Keyword(s):  
Self Assembly ◽  
Amyloid Β ◽  
Structural Elucidation ◽  
The Self ◽  
Assembly Process ◽  
Peptide Nanotubes ◽  
Short Peptide ◽  
X Ray ◽  
X Ray Scattering ◽  
Ray Scattering

This brief report presents an X-ray scattering investigation of self-assembled nanotubes formed by a short peptide. X-ray scattering methods enable multiscale structural elucidation of these nanotubes in solution under the same conditions involved in the self-assembly process. In particular, the dimensions of nanotubes and the crystalline organization within their walls can be determined quantitatively. This is illustrated in the case of amyloid-β(16-22) peptide nanotubes.

scholarly journals Self-assembly of metallosupramolecular rhombi from chiral concave 9,9’-spirobifluorene-derived bis(pyridine) ligands

2014 ◽  
Vol 10 ◽  
pp. 432-441 ◽  
Author(s):  
Rainer Hovorka ◽  
Sophie Hytteballe ◽  
Torsten Piehler ◽  
Georg Meyer-Eppler ◽  
Filip Topić ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nmr Spectroscopy ◽  
Single Crystal ◽  
Self Assembly ◽  
The Self ◽  
Assembly Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Pyridine Ligands ◽  
Racemic Form

Two new 9,9’-spirobifluorene-based bis(4-pyridines) were synthesised in enantiopure and one also in racemic form. These ligands act as concave templates and form metallosupramolecular [(dppp)2M2L2] rhombi with cis-protected [(dppp)Pd]2+ and [(dppp)Pt]2+ ions. The self-assembly process of the racemic ligand preferably occurs in a narcissistic self-recognising manner. Hence, a mixture of all three possible stereoisomers [(dppp)2M2{(R)-L}2](OTf)4, [(dppp)2M2{(S)-L}2](OTf)4, and [(dppp)2M2{(R)-L}{(S)-L}](OTf)4 was obtained in an approximate 1.5:1.5:1 ratio which corresponds to an amplification of the homochiral assemblies by a factor of approximately three as evidenced by NMR spectroscopy and mass spectrometry. The racemic homochiral assemblies could also be characterised by single crystal X-ray diffraction.

Ordered Melanin Film Fabricated by the Self-Assembly Technique

2013 ◽  
Vol 300-301 ◽  
pp. 1385-1388
Author(s):  
Fei Lu
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Self Assembly ◽  
The Self ◽  
Infrared Spectrometry ◽  
X Ray Diffraction ◽  
Si Substrate ◽  
X Ray ◽  
Assembly Technique ◽  
Scanning Electron

In the present article, we obtained uniform and rather flat melanin films with the dendrites structure using self-assembly technique on Si substrate. The structure of film was confirmed by Fourier-transformed infrared spectrometry (FTIR), X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Experimental results showed that the grown on the Si substrate, self-assembly film had oriented quality. Furthermore, according to the results, a model of the secondary structure in the melanin films was also proposed.

Mineralizer Mediated Self-Assembly of PbTiO3 Crystals

2012 ◽  
Vol 184-185 ◽  
pp. 1076-1079
Author(s):  
Hai Yan Lin ◽  
Yong Gang Wang ◽  
Zhan Ying Zhang ◽  
Wei Jun Zhang ◽  
Yu Jiang Wang
Keyword(s):  
Electron Microscopy ◽  
Self Assembly ◽  
Hydrothermal Process ◽  
Spherical Shape ◽  
Xrd Analysis ◽  
The Self ◽  
X Ray Diffraction ◽  
X Ray ◽  
Addition Amount ◽  
Scanning Electron

PbTiO3 crystals with different morphologies, such as flower-like and spherical shape, which was constructed by oriented nanoparticles have been obtained by a simple surfactant-free hydrothermal process assisted by K2CO3 as a mineralizer. Powder X-ray diffraction (XRD) analysis was applied to examine the purity and crystallinity of the as-prepared samples. The morphologies have been characterized by scanning electron microscopy (SEM). The results indicated that the self-assembly structures of PbTiO3 crystals were dependent on the addition amount of K2CO3 and the formation mechanism of the products was briefly discussed.

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 Improving the reactivity of phenylacetylene macrocycles toward topochemical polymerization by side chains modification

2014 ◽  
Vol 10 ◽  
pp. 1613-1619 ◽  
Author(s):  
Simon Rondeau-Gagné ◽  
Jules Roméo Néabo ◽  
Maxime Daigle ◽  
Katy Cantin ◽  
Jean-François Morin
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Raman Spectroscopy ◽  
Self Assembly ◽  
Significant Enhancement ◽  
Side Chains ◽  
X Ray Diffraction ◽  
X Ray ◽  
Topochemical Polymerization ◽  
Scanning Electron

The synthesis and self-assembly of two new phenylacetylene macrocycle (PAM) organogelators were performed. Polar 2-hydroxyethoxy side chains were incorporated in the inner part of the macrocycles to modify the assembly mode in the gel state. With this modification, it was possible to increase the reactivity of the macrocycles in the xerogel state to form polydiacetylenes (PDAs), leading to a significant enhancement of the polymerization yields. The organogels and the PDAs were characterized using Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM).

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