Controlled Design of Mesostructured Titania Based Materials

2002 ◽  
Vol 726 ◽  
Author(s):  
G.J. de A.A. Soler-Illia ◽  
D. Grosso ◽  
E. L. Crepaldi ◽  
F. Cagnol ◽  
C. Sanchez
Keyword(s):  
Self Assembly ◽  
High Surface ◽  
Selective Solvent ◽  
Structured Materials ◽  
Formation Kinetics ◽  
Evaporation Induced Self Assembly ◽  
Metallic Cations ◽  
Titania Films ◽  
Hybrid Xerogels ◽  
Kinetics Of

AbstractMesostructured TiO2-surfactant hybrid xerogels and thin films are prepared by Evaporation-Induced Self Assembly (EISA). These organized structures are reproducibly formed through cooperative self-assembly between hydrophilic Ti-oxo species and a micellar template after selective solvent evaporation from ethanol/HCl/H2O media. The construction of these networks is tailored by tuning the hydrolysis-condensation of the metallic cations with the self-assembly of the organic counterparts (“hydrophilic matching” approach). The hybrids present hexagonal mesostructure (p6m). The formation kinetics of the mesophase is followed by SAXS, interferometry and mass spectrometry (MS) analysis of the vapor phase. An adequate thermal treatment of the organized hybrids leads to high surface (150-400m2 g-1) phosphorus-free mesoporous titania films or powders, with walls containing anatase nanocrystallites. This approach can be successfully extended to other non-silicate based meso-structured materials.

Monodisperse Mesoporous Microparticles Prepared by Evaporation-Induced Self Assembly Within Aerosols

2003 ◽  
Vol 775 ◽  
Author(s):  
Shailendra Rathod ◽  
G. V. Rama Rao ◽  
Brett Andrzejewski ◽  
Gabriel P. López ◽  
Timothy L. Ward ◽  
...  
Keyword(s):  
Pore Size ◽  
Self Assembly ◽  
Swelling Agent ◽  
Aerosol Generator ◽  
Amphiphilic Molecules ◽  
Brij 58 ◽  
Evaporation Induced Self Assembly ◽  
Uptake Process ◽  
Hexagonally Ordered ◽  
Kinetics Of

AbstractEvaporation induced self assembly (EISA) within microdroplets produced by a vibrating orifice aerosol generator (VOAG) has been used to produce monodisperse mesoporous silica particles. This process exploits the concentration of evaporating droplets to induce the organization of various amphiphilic molecules, effectively partitioning the silica precursor (TEOS) to the hydrophilic regions of the structure. Promotion of silica condensation, followed by removal of the surfactant, provides ordered spherical mesoporous particles. Using the VOAG we have produced highly monodisperse particles in the 5 to 10 μm diameter range. The cationic surfactant CTAB typically leads to hexagonal mesostructure with mean pore size of about 2 nm and specific surface area around 900 m2/g. We have also shown that the pore size in CTABtemplated particles can be increased to 3.8 nm by incorporating trimethylbenzene as a swelling agent. The TMB prefentially locates inside and swells the hydrophobic regions of the surfactant mesostructure. Pore size can also be varied by the choice of amphiphile. Hexagonally ordered particles have been produced using the nonionic surfactant Brij-58 and block copolymer F127. These powders possessed mean pore size 2.8 nm and 6.9 nm, respectively. The uptake of alkyl pyridinium chloride molecules have recently been measured, revealing an uptake capacity that is explained by surface adsorption (as opposed to simple pore infiltration). Kinetics of the uptake process are still be analyzed.

scholarly journals Extremely fast electrochromic supercapacitors based on mesoporous WO3 prepared by an evaporation-induced self-assembly

2020 ◽  
Vol 12 (1) ◽  
Author(s):  
Keon-Woo Kim ◽  
Tae Yong Yun ◽  
Sang-Hoon You ◽  
Xiaowu Tang ◽  
Jaeyong Lee ◽  
...  
Keyword(s):  
Energy Storage ◽  
Metal Oxides ◽  
Self Assembly ◽  
High Current Density ◽  
High Surface ◽  
Sol Gel ◽  
Energy Storage Devices ◽  
Mesoporous Metal Oxides ◽  
Evaporation Induced Self Assembly ◽  
Mesoporous Metal

AbstractMesoporous metal oxides consisting of fully interconnected network structures with small pores (20–50 nm) have high surface areas and decreased ion intercalation distances, making them ideal for use in high-performance electrochromic supercapacitors (ECSs). Evaporation-induced self-assembly (EISA), which combines sol–gel chemistry and molecular self-assembly, is a powerful method for the fabrication of mesoporous metal oxides through a solution phase synthesis. Herein, we introduce ultrafast sub-1 s ECSs based on an amorphous mesoporous tungsten trioxide (WO3) that is prepared by EISA. Compared to that of a compact-WO3 film-based device, the performances of an ECS with mesoporous WO3 exhibits a large optical modulation (76% at 700 nm), ultrafast switching speeds (0.8 s for coloration and 0.4 s for bleaching), and a high areal capacitance (2.57 mF/cm2), even at a high current density (1.0 mA/cm2). In addition, the excellent device stability during the coloration/bleaching and charging/discharging cycles is observed under fast response conditions. Moreover, we fabricated a patterned mesoporous WO3 for ECS displays (ECSDs) via printing-assisted EISA (PEISA). The resulting ECSDs can be used as portable energy-storage devices, and their electrochromic reflective displays change color according to their stored energy level. The ECSDs in this work have enormous potential for use in next-generation smart windows for buildings and as portable energy storage displays.

High temperature and water-based evaporation-induced self-assembly approach for facile and rapid synthesis of nanocrystalline mesoporous TiO2

2014 ◽  
Vol 2 (38) ◽  
pp. 15912-15920 ◽  
Author(s):  
Wei Wang ◽  
Dongthanh Nguyen ◽  
Haibo Long ◽  
Guoqiang Liu ◽  
Song Li ◽  
...  
Keyword(s):  
High Temperature ◽  
Self Assembly ◽  
High Surface ◽  
Mesoporous Tio2 ◽  
Rapid Synthesis ◽  
Surface Areas ◽  
Water Based ◽  
Evaporation Induced Self Assembly ◽  
Large Mesopores

Through a high-temperature and water-based EISA (HW-EISA) approach, mesoporous TiO2 with high surface areas, ultra-large mesopores/pore volumes and tuneable bi-crystallinity (anatase plus rutile) can be facilely prepared in a ternary templating system (peroxotitanic acid/P123/H2O).

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 Structure and Formation Kinetics of Millimeter‐Size Single Domain Supercrystals

2021 ◽  
pp. 2101869
Author(s):  
Daniel García‐Lojo ◽  
Evgeny Modin ◽  
Sergio Gómez‐Graña ◽  
Marianne Impéror‐Clerc ◽  
Andrey Chuvilin ◽  
...  
Keyword(s):  
Single Domain ◽  
Formation Kinetics ◽  
Kinetics Of

scholarly journals Controlling the Kinetics of an Enzymatic Reaction through Enzyme or Substrate Confinement into Lipid Mesophases with Tunable Structural Parameters

2020 ◽  
Vol 21 (14) ◽  
pp. 5116
Author(s):  
Marco Mendozza ◽  
Arianna Balestri ◽  
Costanza Montis ◽  
Debora Berti
Keyword(s):  
Reaction Kinetics ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Structural Parameters ◽  
Enzymatic Reaction ◽  
X Ray Scattering ◽  
Nitrophenyl Phosphate ◽  
Vis Spectroscopy ◽  
Kinetics Of ◽  
Enzyme Alkaline Phosphatase

Lipid liquid crystalline mesophases, resulting from the self-assembly of polymorphic lipids in water, have been widely explored as biocompatible drug delivery systems. In this respect, non-lamellar structures are particularly attractive: they are characterized by complex 3D architectures, with the coexistence of hydrophobic and hydrophilic regions that can conveniently host drugs of different polarities. The fine tunability of the structural parameters is nontrivial, but of paramount relevance, in order to control the diffusive properties of encapsulated active principles and, ultimately, their pharmacokinetics and release. In this work, we investigate the reaction kinetics of p-nitrophenyl phosphate conversion into p-nitrophenol, catalysed by the enzyme Alkaline Phosphatase, upon alternative confinement of the substrate and of the enzyme into liquid crystalline mesophases of phytantriol/H2O containing variable amounts of an additive, sucrose stearate, able to swell the mesophase. A structural investigation through Small-Angle X-ray Scattering, revealed the possibility to finely control the structure/size of the mesophases with the amount of the included additive. A UV–vis spectroscopy study highlighted that the enzymatic reaction kinetics could be controlled by tuning the structural parameters of the mesophase, opening new perspectives for the exploitation of non-lamellar mesophases for confinement and controlled release of therapeutics.

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