scholarly journals STUDY OF THE FORMATION OF MESOPOROUS TiO2 USING ISOPROPOXIDE PRECURSORS UNDER LESS WATER CONDITIONS

2010 ◽  
Vol 5 (1) ◽  
pp. 15-22 ◽  
Author(s):  
Indriana Kartini ◽  
Gao Qing Lu
Keyword(s):  
Self Assembly ◽  
Isopropyl Alcohol ◽  
Molar Ratio ◽  
Mesoporous Titania ◽  
Synthesis Parameters ◽  
Water Conditions ◽  
Evaporation Induced Self Assembly ◽  
Added Water ◽  
Templating Synthesis

The role of the synthesis parameters (the molar ratio of template, isopropyl alcohol, acetylacetone, and water with respect to titanium(IV) tetraisopropoxide) has been thoroughly investigated to understand their effects on the mesostructures and the formation of crystalline phases of mesoporous titania xerogels in less water condition (no added water) at 60 oC. The resultant mesoporous titania are more likely to have worm-hole like structure as the dominant stable structure. The template appears to play no significant role in structure directing at mesophase level. However, increasing the amount of the template delays the formation of anatase crystalline phase   Keywords: mesoporous titania, templating synthesis, anatase, evaporation-induced self-assembly

scholarly journals Synthesis of magnetic mesoporous titania colloidal crystals through evaporation induced self-assembly in emulsion as effective and recyclable photocatalysts

2015 ◽  
Vol 17 (41) ◽  
pp. 27653-27657 ◽  
Author(s):  
Jeffrey E. Chen ◽  
Hong-Yuan Lian ◽  
Saikat Dutta ◽  
Saad M. Alshehri ◽  
Yusuke Yamauchi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Self Assembly ◽  
Colloidal Crystal ◽  
Colloidal Crystals ◽  
Mesoporous Titania ◽  
Evaporation Induced Self Assembly

This study illustrates the directed self-assembly of mesoporous TiO2 with magnetic properties due to its colloidal crystal structure with Fe3O4.

Effect of Pore Size on the Hydrophilicity in Dark of TiO2 Films

2011 ◽  
Vol 130-134 ◽  
pp. 1049-1053
Author(s):  
Qi Wang ◽  
Cheng Pu Lin ◽  
Peng Cui
Keyword(s):  
Contact Angle ◽  
Organic Matter ◽  
Pore Size ◽  
Self Assembly ◽  
Dip Coating ◽  
Molar Ratio ◽  
Water Contact ◽  
Coating Method ◽  
Evaporation Induced Self Assembly ◽  
Dip Coating Method

Mesoporous TiO2 films was prepared by evaporation-induced self-assembly and dip-coating method. And the pore size of the TiO2 films is adjusted by controlling the molar ratio of H2O/TiO2 (H value). Water contact angle was chosen to represent the hydrophilic property, and XRD and AFM were carried out to characterize the films. With the increase of H value, the pore size increased firstly then decreased. And when H is 15, the pore size is the biggest, which hydrophilicity in dark is the best too. With the extention of the non-irridation time, the hydrophilicity is worse. And the reason may be ascribed to the adsorption of organic matter in air.

scholarly journals Synthesis and Characterization of Nanoporous Carbon Materials; The Effect of Surfactant Concentrations and Salts

2011 ◽  
Vol 8 (1) ◽  
pp. 196-200 ◽  
Author(s):  
Shokoofeh Geranmayeh ◽  
Alireza Abbasi ◽  
Alireza Badiei
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Self Assembly ◽  
Nanoporous Carbon ◽  
Pluronic F127 ◽  
Molar Ratio ◽  
Soft Template ◽  
Carbon Framework ◽  
Evaporation Induced Self Assembly

Nanoporous carbon framework was synthesized using phenol and formaldehyde as carbon precursors and triblock copolymer (pluronic F127) as soft templateviaevaporation induced self-assembly. Hexagonal mesoporous carbon with specific surface area of 350 m2/g through optimizing the situation was obtained. The effects of different surfactant/phenol molar ratio and presence of salts on specific surface area, pore size and pore volume for all the prepared samples were studied by means of the Brunauer-Emmett-Teller (BET) formalism, powder X-ray diffraction technique and FT-IR spectroscopy.

Directive Effect of Chain Length in Modulating Peptide Nano-assemblies

2020 ◽  
Vol 27 (9) ◽  
pp. 923-929
Author(s):  
Gaurav Pandey ◽  
Prem Prakash Das ◽  
Vibin Ramakrishnan
Keyword(s):  
Electron Microscopy ◽  
Amino Acids ◽  
Light Scattering ◽  
Chain Length ◽  
Self Assembly ◽  
The Self ◽  
Ionic Charge ◽  
Self Assembling ◽  
Biophysical Techniques

Background: RADA-4 (Ac-RADARADARADARADA-NH2) is the most extensively studied and marketed self-assembling peptide, forming hydrogel, used to create defined threedimensional microenvironments for cell culture applications. Objectives: In this work, we use various biophysical techniques to investigate the length dependency of RADA aggregation and assembly. Methods: We synthesized a series of RADA-N peptides, N ranging from 1 to 4, resulting in four peptides having 4, 8, 12, and 16 amino acids in their sequence. Through a combination of various biophysical methods including thioflavin T fluorescence assay, static right angle light scattering assay, Dynamic Light Scattering (DLS), electron microscopy, CD, and IR spectroscopy, we have examined the role of chain-length on the self-assembly of RADA peptide. Results: Our observations show that the aggregation of ionic, charge-complementary RADA motifcontaining peptides is length-dependent, with N less than 3 are not forming spontaneous selfassemblies. Conclusion: The six biophysical experiments discussed in this paper validate the significance of chain-length on the epitaxial growth of RADA peptide self-assembly.

Role of the Structure and Electronic Properties of Fe2O3-MoO3 Catalyst on the Dehydration of Isopropyl Alcohol

1993 ◽  
Vol 58 (7) ◽  
pp. 1591-1599 ◽  
Author(s):  
Abd El-Aziz A. Said
Keyword(s):  
Active Sites ◽  
Isopropyl Alcohol ◽  
Oxide Catalyst ◽  
Flow System ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalyst Composition ◽  
Surface Active

Molybdenum oxide catalyst doped or mixed with (1 - 50) mole % Fe3+ ions were prepared. The structure of the original samples and the samples calcined at 400 °C were characterized using DTA, X-ray diffraction and IR spectra. Measurements of the electrical conductivity of calcined samples with and without isopropyl alcohol revealed that the conductance increases on increasing the content of Fe3+ ions up to 50 mole %. The activation energies of charge carriers were determined in presence and absence of the alcohol. The catalytic dehydration of isopropyl alcohol was carried out at 250 °C using a flow system. The results obtained showed that the doped or mixed catalysts are active and selective towards propene formation. However, the catalyst containing 40 mole % Fe3+ ions exhibited the highest activity and selectivity. Correlations were attempted to the catalyst composition with their electronic and catalytic properties. Probable mechanism for the dehydration process is proposed in terms of surface active sites.

Sticky ends in a self-assembling ABA triblock copolymer: the role of ureas in stimuli-responsive hydrogels

2019 ◽  
Vol 4 (1) ◽  
pp. 91-102 ◽  
Author(s):  
Ryan T. Shafranek ◽  
Joel D. Leger ◽  
Song Zhang ◽  
Munira Khalil ◽  
Xiaodan Gu ◽  
...  
Keyword(s):  
Self Assembly ◽  
Viscoelastic Properties ◽  
Triblock Copolymer ◽  
Thermal Response ◽  
Stimuli Responsive ◽  
Self Assembling ◽  
Polymeric Hydrogels ◽  
Aba Triblock Copolymer ◽  
Responsive Hydrogels

Directed self-assembly in polymeric hydrogels allows tunability of thermal response and viscoelastic properties.

scholarly journals Understanding the role of conjugation length on the self-assembly behaviour of oligophenyleneethynylenes

2021 ◽  
Author(s):  
Beatriz Matarranz ◽  
Goutam Ghosh ◽  
Ramesh Kandanelli ◽  
Angel Sampedro ◽  
Kalathil K. Kartha ◽  
...  
Keyword(s):  
Self Assembly ◽  
The Self ◽  
Conjugation Length ◽  
The Relationship

We unravel the relationship between conjugation length and self-assembly behaviour of oligophenyleneethynylenes (OPEs).

scholarly journals On the Role of Peripheral H‐bonding Directors in the Tubular Self‐assembly of Dinucleobase Monomers

ChemPlusChem ◽  
2021 ◽  
Author(s):  
Violeta Vázquez-González ◽  
María J. Mayoral ◽  
Fatima Aparicio ◽  
Paula Martínez-Arjona ◽  
David Gonzalez Rodriguez
Keyword(s):  
Self Assembly

scholarly journals Interactions between an Associative Amphiphilic Block Polyelectrolyte and Surfactants in Water: Effect of Charge Type on Solution Properties and Aggregation

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1729
Author(s):  
Patrizio Raffa
Keyword(s):  
Surface Tension ◽  
Self Assembly ◽  
Interaction Model ◽  
Industrial Applications ◽  
Molecular Organization ◽  
Different Types ◽  
Solution Rheology ◽  
Interesting Class ◽  
First Time

The study of interactions between polyelectrolytes (PE) and surfactants is of great interest for both fundamental and applied research. These mixtures can represent, for example, models of self-assembly and molecular organization in biological systems, but they are also relevant in industrial applications. Amphiphilic block polyelectrolytes represent an interesting class of PE, but their interactions with surfactants have not been extensively explored so far, most studies being restricted to non-associating PE. In this work, interactions between an anionic amphiphilic triblock polyelectrolyte and different types of surfactants bearing respectively negative, positive and no charge, are investigated via surface tension and solution rheology measurements for the first time. It is evidenced that the surfactants have different effects on viscosity and surface tension, depending on their charge type. Micellization of the surfactant is affected by the presence of the polymer in all cases; shear viscosity of polymer solutions decreases in presence of the same charge or nonionic surfactants, while the opposite charge surfactant causes precipitation. This study highlights the importance of the charge type, and the role of the associating hydrophobic block in the PE structure, on the solution behavior of the mixtures. Moreover, a possible interaction model is proposed, based on the obtained data.

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