scholarly journals Preparation of Cage Nanoporous Silica and Its Application in Chromatographic Fillers

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Liang Hongyan
Keyword(s):  
Polyethylene Oxide ◽  
Self Assembly ◽  
Pore Volume ◽  
Hydrothermal Reaction ◽  
Synthesis Method ◽  
Hydrothermal Condition ◽  
Nanoporous Silica ◽  
X Ray ◽  
Silicon Source ◽  
Poly Propylene

In this paper, the cage nanoporous silica is composed of ethyl orthosilicate as silicon source, triblock copolymerpoly (ethylene oxide) -poly (propylene oxide) -polyethylene oxide (F127) as structure guide agent and additive, whilethe Fm3m cubic structure of cage type nanoporous silica was prepared by hydrothermal synthesis method. It is easyto control the self-assembly of the silica triblock copolymer intermediates thermally. In addition, the change in samplepore size and pore volume can be achieved by a hydrothermal reaction at a temperature of 100 ° C to 150 °C. Smallangle X-ray diff raction shows that these samples have ordered pores, while adsorption studies show that they havehigh porosity, uniform distribution of bimodal pores and large pore volume. Use separation of p-methylbenzene borate,iodobenzene and biphenyl by using three kinds of cage-type nanoporous silica materials as chromatographic fi llers. Theresults showed that the material prepared at 130 ℃ under hydrothermal condition had the best eff ect on the separationof three organic compounds.

Defining Structure in Electrospun Polymer Fibres

2008 ◽  
Vol 55-57 ◽  
pp. 33-36
Author(s):  
G.R. Mitchell ◽  
M. Belal ◽  
F.J. Davis ◽  
D.E. Elliott ◽  
M. Kariduraganavar ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Polyethylene Oxide ◽  
Self Assembly ◽  
Vinyl Alcohol ◽  
Poly Vinyl Alcohol ◽  
X Ray ◽  
Amorphous System ◽  
Composite Systems ◽  
X Ray Scattering ◽  
Nano Size

We use a combination of microscopy, x-ray scattering and neutron scattering to show how structure develops in micro and nano-size polymer fibres prepared by electrospinning. The technique has been applied to a range of different polymers, an amorphous system (polystyrene), a crystallisable polymer (poly-ε-caprolactone), a composite systems (polyethylene oxide or poly vinyl alcohol containing polypyrrole) and consider the possibility of self assembly (gelatin).

scholarly journals Garcinia Mangostana Peel Extract as Sustainable Fuel Source on Ceria Synthesis under Hydrothermal Condition

2019 ◽  
Vol 8 (3) ◽  
pp. 255-261
Author(s):  
Salprima Yudha S ◽  
◽  
Morina Adfa ◽  
Aswin Falahudin ◽  
Deni Agus Triawan ◽  
...  
Keyword(s):  
Crystal Size ◽  
Hydrothermal Reaction ◽  
Hydrothermal Condition ◽  
Fluorite Structure ◽  
X Ray Diffraction ◽  
Garcinia Mangostana ◽  
Reaction Conditions ◽  
Xrd Pattern ◽  
X Ray ◽  
Fuel Source

Cerium (IV) oxide or ceria (CeO2) was fabricated by heating an aqueous extract of Garcinia mangostana and cerium (III) nitrate in hydrothermal autoclave reactor at 200 °C for 3 hours, followed by calcination at 600 °C for 5 hours. The powder X-ray diffraction (XRD) pattern of the precipitate from cerium(III) nitrate under hydrothermal reaction conditions shows no clear XRD peaks, indicating its amorphous nature. In contrast, the products from the calcinated samples exhibit XRD peaks, which correspond to cubic fluorite structure with an average crystal size of 7.55 nm. The elemental mapping using the energy-dispersive X-ray (EDX) analysis reveals the main elements present were cerium and oxygen, with minor impurities in low amounts. The presence of Garcinia mangostana extract is predicted to be the key component and fuel source to obtain CeO2 particles with narrow crystal size.

Preparation and Characterization of MoS2 Microsphere by Hydrothermal Method

2013 ◽  
Vol 631-632 ◽  
pp. 306-309 ◽  
Author(s):  
Ya Ru Cui ◽  
Jiang Shan He ◽  
Xiao Ming Li ◽  
Jun Xue Zhao ◽  
Ao Li Chen ◽  
...  
Keyword(s):  
Self Assembly ◽  
Hydrothermal Reaction ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Sem Images ◽  
Ammonium Heptamolybdate ◽  
X Ray ◽  
Influence Mechanism ◽  
Dispersing Agent

In this work, MoS2 microsphere was synthesized by hydrothermal reaction, in which thiourea (CS(NH2)2) was used as S-source and reducing agent, ammonium heptamolybdate ((NH4)6Mo7O24.4H2O) was used as Mo-source. The influence of temperature, as well as different dispersing agents, on the reaction product’s morphology, structure and phase composition was discussed. X-ray diffraction results show that all the as-synthesized products are the hexagonal 2H-MoS2 without impurity. SEM images of the as-prepared MoS2 samples without adding any dispersing agent present spherical morphology with sheet-like structures shaped on the surface. A possible formation mechanism of the MoS2 microsphere is that of self-assembly growth process; In addition, for the samples adding surfactant CTAB, SDBS or PVP in the reactants, the MoS2 is confined to layered structure. Compared with SDBS and PVP, CTAB has the best dispersion effect which ensure the as-synthesized microsphere with about 300nm average diameter, and the influence mechanism of which can be deduced as electrostatic interaction and stereo-hindrance effect.

In situ Time-Resolved Small-Angle X-ray Scattering Reveals the Formation Kinetics of Polyelectrolyte Complex Micelles

2019 ◽  
Author(s):  
Hao Wu ◽  
Jeffrey Ting ◽  
Siqi Meng ◽  
Matthew Tirrell
Keyword(s):  
Small Angle ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Polyelectrolyte Complex ◽  
Time Resolved ◽  
X Ray ◽  
X Ray Scattering ◽  
Kinetics Of ◽  
Ray Scattering

We have directly observed the <i>in situ</i> self-assembly kinetics of polyelectrolyte complex (PEC) micelles by synchrotron time-resolved small-angle X-ray scattering, equipped with a stopped-flow device that provides millisecond temporal resolution. This work has elucidated one general kinetic pathway for the process of PEC micelle formation, which provides useful physical insights for increasing our fundamental understanding of complexation and self-assembly dynamics driven by electrostatic interactions that occur on ultrafast timescales.

scholarly journals Self-Assembled Bimetallic Aluminum-Salen Catalyst for the Cyclic Carbonates Synthesis

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 4097
Author(s):  
Wooyong Seong ◽  
Hyungwoo Hahm ◽  
Seyong Kim ◽  
Jongwoo Park ◽  
Khalil A. Abboud ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Self Assembly ◽  
Reaction Pathway ◽  
Kinetic Studies ◽  
Cyclic Carbonate ◽  
Reaction Conditions ◽  
Formation Reaction ◽  
X Ray ◽  
Carbonate Formation ◽  
Salen Aluminum

Bimetallic bis-urea functionalized salen-aluminum catalysts have been developed for cyclic carbonate synthesis from epoxides and CO2. The urea moiety provides a bimetallic scaffold through hydrogen bonding, which expedites the cyclic carbonate formation reaction under mild reaction conditions. The turnover frequency (TOF) of the bis-urea salen Al catalyst is three times higher than that of a μ-oxo-bridged catalyst, and 13 times higher than that of a monomeric salen aluminum catalyst. The bimetallic reaction pathway is suggested based on urea additive studies and kinetic studies. Additionally, the X-ray crystal structure of a bis-urea salen Ni complex supports the self-assembly of the bis-urea salen metal complex through hydrogen bonding.

scholarly journals Thermoelectric Generator Using Polyaniline-Coated Sb2Se3/β-Cu2Se Flexible Thermoelectric Films

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1518
Author(s):  
Minsu Kim ◽  
Dabin Park ◽  
Jooheon Kim
Keyword(s):  
Electron Microscopy ◽  
Electrical Conductivity ◽  
Field Emission ◽  
Photoelectron Spectroscopy ◽  
Thermoelectric Generator ◽  
Hydrothermal Reaction ◽  
Water Evaporation ◽  
Pani Film ◽  
Portable Devices ◽  
X Ray

Herein, Sb2Se3 and β-Cu2Se nanowires are synthesized via hydrothermal reaction and water evaporation-induced self-assembly methods, respectively. The successful syntheses and morphologies of the Sb2Se3 and β-Cu2Se nanowires are confirmed via X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, field emission scanning electron microscopy (FE-SEM), and field emission transmission electron microscopy (FE-TEM). Sb2Se3 materials have low electrical conductivity which limits application to the thermoelectric generator. To improve the electrical conductivity of the Sb2Se3 and β-Cu2Se nanowires, polyaniline (PANI) is coated onto the surface and confirmed via Fourier-transform infrared spectroscopy (FT-IR), FE-TEM, and XPS analysis. After coating PANI, the electrical conductivities of Sb2Se3/β-Cu2Se/PANI composites were increased. The thermoelectric performance of the flexible Sb2Se3/β-Cu2Se/PANI films is then measured, and the 70%-Sb2Se3/30%-β-Cu2Se/PANI film is shown to provide the highest power factor of 181.61 μW/m·K2 at 473 K. In addition, a thermoelectric generator consisting of five legs of the 70%-Sb2Se3/30%-β-Cu2Se/PANI film is constructed and shown to provide an open-circuit voltage of 7.9 mV and an output power of 80.1 nW at ΔT = 30 K. This study demonstrates that the combination of inorganic thermoelectric materials and flexible polymers can generate power in wearable or portable devices.

scholarly journals Efficient Adsorption of Methylene Blue by Porous Biochar Derived from Soybean Dreg Using a One-Pot Synthesis Method

Molecules ◽  
2021 ◽  
Vol 26 (3) ◽  
pp. 661
Author(s):  
Zhiwei Ying ◽  
Xinwei Chen ◽  
He Li ◽  
Xinqi Liu ◽  
Chi Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Methylene Blue ◽  
Photoelectron Spectroscopy ◽  
Synthesis Method ◽  
Urban Pollution ◽  
Maximum Adsorption Capacity ◽  
One Pot ◽  
Average Pore ◽  
X Ray ◽  
Isotherm Equation

Soybean dreg is a by-product of soybean products production, with a large consumption in China. Low utilization value leads to random discarding, which is one of the important sources of urban pollution. In this work, porous biochar was synthesized using a one-pot method and potassium bicarbonate (KHCO3) with low-cost soybean dreg (SD) powder as the carbon precursor to investigating the adsorption of methylene blue (MB). The prepared samples were characterized with scanning electron microscopy (SEM), transmission electron microscopy (TEM), elemental analyzer (EA), Brunauer-Emmett-Teller (BET), X-ray diffractometer (XRD), Raman spectroscopy (Raman), Fourier transform infrared spectrometer (FTIR), and X-ray photoelectron spectroscopy (XPS). The obtained SDB-K-3 showed a high specific surface area of 1620 m2 g−1, a large pore volume of 0.7509 cm3 g−1, and an average pore diameter of 1.859 nm. The results indicated that the maximum adsorption capacity of SDB-K-3 to MB could reach 1273.51 mg g−1 at 318 K. The kinetic data were most consistent with the pseudo-second-order model and the adsorption behavior was more suitable for the Langmuir isotherm equation. This study demonstrated that the porous biochar adsorbent can be prepared from soybean dreg by high value utilization, and it could hold significant potential for dye wastewater treatment in the future.

Invariant and Variable Supramolecular Self-Assembly in 6-Substituted Uracil Derivatives: Insights from X-ray Structures and Quantum Chemical Study

2021 ◽  
Author(s):  
Lamya H. Al-Wahaibi ◽  
Sai Ramya Sree Bysani ◽  
Samar S. Tawfik ◽  
Mohammed S. M. Abdelbaky ◽  
Santiago Garcia-Granda ◽  
...  
Keyword(s):  
Self Assembly ◽  
Quantum Chemical ◽  
Quantum Chemical Study ◽  
Chemical Study ◽  
X Ray ◽  
Uracil Derivatives

scholarly journals Improvement of the thermal stability of dendritic silver-coated copper microparticles by surface modification based on molecular self-assembly

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Tae Hyeong Kim ◽  
Hyeji Kim ◽  
Hyo Jun Jang ◽  
Nara Lee ◽  
Kwang Hyun Nam ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Electrically Conductive ◽  
X Ray ◽  
Alkyl Chains ◽  
Conductive Film ◽  
Initial Resistance ◽  
Thermal Stability Of ◽  
Scanning Electron

AbstractIn the study reported herein, silver-coated copper (Ag/Cu) powder was modified with alkanethiols featuring alkyl chains of different lengths, namely butyl, octyl, and dodecyl, to improve its thermal stability. The modification of the Ag/Cu powders with adsorbed alkanethiols was confirmed by scanning electron microscopy with energy dispersive spectroscopy, X-ray photoelectron spectroscopy, and thermogravimetric analysis. Each powder was combined with an epoxy resin to prepare an electrically conductive film. The results confirmed that the thermal stability of the films containing alkanethiol-modified Ag/Cu powders is superior to that of the film containing untreated Ag/Cu powder. The longer the alkyl group in the alkanethiol-modified Ag/Cu powder, the higher the initial resistance of the corresponding electrically conductive film and the lower the increase in resistance induced by heat treatment.

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