scholarly journals Kinetic Influence of Siliceous Reactions on Structure Formation of Mesoporous Silica Formed via the Co-Structure Directing Agent Route

2016 ◽  
Vol 120 (7) ◽  
pp. 3814-3821 ◽  
Author(s):  
Ruiyu Lin ◽  
Göran Carlström ◽  
Quoc Dat Pham ◽  
Michael W. Anderson ◽  
Daniel Topgaard ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Structure Formation ◽  
Structure Directing Agent

Preparation of Organized Mesoporous Silica from Sodium Metasilicate Solutions in Alkaline Medium Using Nonionic Surfactants

2003 ◽  
Vol 68 (10) ◽  
pp. 2019-2031 ◽  
Author(s):  
Markéta Zukalová ◽  
Jiří Rathouský ◽  
Arnošt Zukal
Keyword(s):  
Mesoporous Silica ◽  
Ethylene Oxide ◽  
Sodium Metasilicate ◽  
Spherical Particles ◽  
Structure Directing Agent ◽  
Inorganic Species ◽  
Poly Ethylene Oxide ◽  
Acidic Conditions ◽  
Poly Ethylene ◽  
Hydrolysis Of

A new procedure has been developed, which is based on homogeneous precipitation of organized mesoporous silica from an aqueous solution of sodium metasilicate and a nonionic poly(ethylene oxide) surfactant serving as a structure-directing agent. The decrease in pH, which induces the polycondensation of silica, is achieved by hydrolysis of ethyl acetate. Owing to the complexation of Na+ cations by poly(ethylene oxide) segments, assembling of the mesostructure appears to occur under electrostatic control by the S0Na+I- pathway, where S0 and I- are surfactant and inorganic species, respectively. As the complexation of Na+ cations causes extended conformation of poly(ethylene oxide) segments, the pore size and pore volume of organized mesoporous silica increase in comparison with materials prepared under neutral or acidic conditions. The assembling of particles can be fully separated from their solidification, which results in the formation of highly regular spherical particles of mesoporous silica.

Monolithic Macroporous-Mesoporous Carbon Using Ionic Liquids as Carbon Source

2014 ◽  
Vol 988 ◽  
pp. 23-26
Author(s):  
Ai Bing Chen ◽  
Yun Hong Yu ◽  
Yi Feng Yu ◽  
Hai Jun Lv ◽  
Ting Ting Xing ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Carbon Source ◽  
Mesoporous Silica ◽  
Mesoporous Carbon ◽  
Structure Directing Agent ◽  
Silica Source ◽  
Pu Foam ◽  
Silica Materials ◽  
Mesoporous Silica Materials ◽  
Ordered Macroporous

A facile approach is employed for the preparation of hierarchically porous structures monolithic ordered macroporous-mesoporous silica materials (OMS) using the commercially available and cheap polyurethane (PU) foam as monolithic template, triblock copolymer P123 (EO20PO70EO20) as structure-directing agent and tetraethyl orthosilicate (TEOS) as silica source, then monolithic ordered macro porous-mesoporous carbon materials (OMC) is synthesized by using monolithic ordered macroporous-mesoporous silica materials as hard template and ionic liquids as the carbon source. The silica and carbon monoliths possess uniform pore sizes (3.74-3.84 nm) and ordered mesostructure.

Efficient Removal of Cd2+ by the Mesoporous Silica Functionalized by APTES

2013 ◽  
Vol 726-731 ◽  
pp. 2409-2412
Author(s):  
Xiao Feng Cai ◽  
Kang Wei Ji ◽  
Wan Hao Wu ◽  
Jie Hou ◽  
Shi You Hao
Keyword(s):  
Aqueous Solution ◽  
Mesoporous Silica ◽  
Ph Value ◽  
High Surface ◽  
High Surface Area ◽  
Efficient Removal ◽  
Structure Directing Agent ◽  
Functionalized Mesoporous Silica ◽  
Adsorption Desorption ◽  
Large Pore Size

Amino-functionalized mesoporous silica (AFMS) with high amino loading, high surface area, and large pore size was synthesized using the anionic surfactant N-lauroylsarcosine sodium (Sar-Na) as template and 3-aminopropyltriethoxysilane (APTES) as co-structure directing agent (CSDA). The synthesized AFMS was characterized by N2adsorption-desorption, TEM and elemental analyzer. The results of the removal of Cd2+from aqueous solution showed that the pH value of aqueous solution affected the removal efficiency of Cd2+greatly, and that unary adsorption isotherm of Cd2+on the AFMS was well described by the Sips isotherm model, in which the adsorption capacity was 2.43 mmol/g for Cd2+, much higher than the literature data.

scholarly journals Hybrid mesoporous silica with controlled drug release

2019 ◽  
Vol 84 (9) ◽  
pp. 1027-1039 ◽  
Author(s):  
László Almásy ◽  
Ana-Maria Putz ◽  
Qiang Tian ◽  
Gennady Kopitsa ◽  
Tamara Khamova ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Drug Release ◽  
Mesoporous Silica ◽  
Drug Loading ◽  
Sol Gel ◽  
Nitrogen Adsorption ◽  
Controlled Drug Release ◽  
Ammonium Bromide ◽  
Structure Directing Agent ◽  
One Step

The mesoporous silica particles were prepared by the sol?gel method in one-step synthesis, in acidic conditions, from tetraethoxysilane (TEOS) and methyltriethoxysilane (MTES), varying the mole ratio of the silica precursors. Nitric acid was used as catalyst at room temperature and hexadecyltrimethyl ammonium bromide (CTAB) as structure directing agent. Optical properties, porosity and microstructure of the materials in function of the MTES/TEOS ratio were evaluated using infrared spectroscopy, nitrogen adsorption and small angle X-ray scattering. All materials showed the ordered pore structure and the high specific surfaces, making them suitable as the drug delivery systems. Drug loading and release tests using ketoprofen were performed to assess their performance for drug delivery applications. The amount of the methylated precursor used in the synthesis had little effect on the drug loading capacity, but had a strong influence on the initial rate of the drug release.

Synthesis of SBA-15/MCM-41 bimodal mesoporous silica

2016 ◽  
Vol 1817 ◽  
Author(s):  
Leyla Y. Jaramillo ◽  
Wilson A. Henao ◽  
Elizabeth Pabón-Gelves
Keyword(s):  
Mesoporous Silica ◽  
Textural Properties ◽  
New Materials ◽  
X Ray Diffraction ◽  
Main Interest ◽  
Structure Directing Agent ◽  
X Ray ◽  
Synthesis Parameters ◽  
Nanostructured Silica ◽  
Mcm 41

ABSTRACTNanostructured silica materials with different morphologies and adjustable pore size have been studied by researches worldwide for several applications such as catalysis, separation, adsorption, and templates for new materials. The main interest in the development of these materials is to obtain a structure with a specific combination of pore sizes for a particular application. The morphology and textural properties of pores can be easily changed with the modification of the synthesis parameters, among these, the choice of surfactant or structure directing agent (SDA).Accordingly, in this work, three types of nanostructured silica with different mesoporosity were synthesized by using of CTAB and Pluronic 123 as structure directing agents: SBA-15 and MCM-41 unimodal mesoporous silica and SBA-15/MCM-41 bimodal mesoporous silica.To evaluate the effect of surfactant on the morphology and textural properties of pores, the materials were characterized by scanning electron microscopy (SEM), X-ray Diffraction (XRD) and nitrogen sorption (BET).

Synthesis and Characterization of New Mesoporous Silica Film Materials for Explosive Detection

2013 ◽  
Vol 652-654 ◽  
pp. 1912-1915 ◽  
Author(s):  
Li Ma ◽  
Yu Quan Wen ◽  
Nan Yan
Keyword(s):  
Mesoporous Silica ◽  
Sol Gel ◽  
High Sensitivity ◽  
Silica Film ◽  
Hexagonal Structure ◽  
Structure Directing Agent ◽  
Silica Films ◽  
State Terrorism ◽  
Quenching Efficiency ◽  
Fluorescence Dye

Trace explosives detection plays a more and more important role in military, civilian and opposition to state terrorism application. Through sol-gel technique and spin coating technology, three different types of surfactants as structure-directing agent， a series of different pore size mesoporous silica thin films with two-dimensional hexagonal structure doped by silylated naphthol fluorescence dye were successfully fabricated. By using fluorescence spectra method, different films doping fluorescence dye were sensed toward nitro explosive vapor such as 2,4,6-trinitrotoluene (TNT), 1,3,5-trinitro-1,3,5-triazacyclohexane (RDX), octahydro -1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX), and exhibit rapid response rate and extremely high fluorescent quenching efficiency, close to 72% after 60s response to TNT. The results clearly show that mesoporous silica films, with different porous size and structure, easily to be prepared and own high sensitivity, could be used as a new alternative of trace explosive detecting material.

scholarly journals Proton Transport in Mesoporous Silica SBA-16 Thin Films With Three-Dimensional Cubic Structures

2013 ◽  
Author(s):  
Junho Hwang ◽  
Hirofumi Daiguji
Keyword(s):  
Thin Films ◽  
Mesoporous Silica ◽  
Aqueous Solutions ◽  
Surface Charge ◽  
Electric Fields ◽  
Proton Transport ◽  
Ionic Current ◽  
Dip Coating ◽  
Structure Directing Agent ◽  
Assembly Method

Mesoporous silica SBA-16 thin films with highly ordered 3D cubic structures were synthesized by evaporation-induced self-assembly method, using an F127 triblock copolymer as the structure-directing agent via dip coating, to investigate proton transport of aqueous solutions confined in mesopores. Using electrochemical measurements of ionic current under DC electric fields, we elucidated proton transport phenomena through mesopores of SBA-16 thin films. At low concentrations, ranging from 10−7 to 10−5 M, the I–V curves of KCl and HCl aqueous solutions were nonlinear. However, at 10−4 and 10−3 M, while I–V curves of KCl aqueous solutions displayed nonlinear behavior, those of HCl aqueous solutions were almost linear. The linear behavior can be attributed to a decrease in the electric potential barrier owing to a reduction in the surface charge density, which is caused by the protonation of silanol groups on the inner surface of mesopores. At high concentrations, ranging from 10−2 to 1 M, the I–V curves of KCl and HCl aqueous solutions were almost linear because the effect of surface charge of mesopores on ion transport was marginal.

scholarly journals The Design of Anionic Surfactant-Based Amino-Functionalized Mesoporous Silica Nanoparticles and their Application in Transdermal Drug Delivery

Pharmaceutics ◽  
2020 ◽  
Vol 12 (11) ◽  
pp. 1035
Author(s):  
Aliyah Almomen ◽  
Ahmed M. El-Toni ◽  
Mohammed Badran ◽  
Adel Alhowyan ◽  
Mohd Abul Kalam ◽  
...  
Keyword(s):  
Mesoporous Silica ◽  
Silica Nanoparticles ◽  
Anionic Surfactant ◽  
Mesoporous Silica Nanoparticles ◽  
Synergetic Effect ◽  
Melanoma Cells ◽  
Skin Permeability ◽  
Loading Capacity ◽  
Structure Directing Agent ◽  
Functionalized Mesoporous Silica

Melanoma remains the most lethal form of skin cancer and most challenging to treat despite advances in the oncology field. Our work describes the utilization of nanotechnology to target melanoma locally in an attempt to provide an advanced and efficient quality of therapy. Amino-functionalized mesoporous silica nanoparticles (MSN-NH2) were developed in situ through the utilization of anionic surfactant and different volumes of 3-aminopropyltriethoxysilane (APTES) as a co-structure directing agent (CSDA). Prepared particles were characterized for their morphology, particles size, 5-flurouracol (5-FU) and dexamethasone (DEX) loading capacity and release, skin penetration, and cytotoxicity in vitro in HT-144 melanoma cells. Results of transmission electron microscopy (TEM) and nitrogen adsorption–desorption isotherm showed that using different volumes of APTES during the functionalization process had an impact on the internal and external morphology of the particles, as well as particle size. However, changing the volume of APTES did not affect the diameter of formed mesochannels, which was about 4 nm. MSN-NH2 showed a relatively high loading capacity of 5-FU (12.6 ± 5.5) and DEX (44.72 ± 4.21) when using drug: MSN-NH2 ratios of 5:1 for both drugs. The release profile showed that around 83% of 5-FU and 21% of DEX were released over 48 h in pH 7.4. The skin permeability study revealed that enhancement ratio of 5-Fu and DEX using MSN-NH2 were 4.67 and 5.68, respectively, relative to their free drugs counterparts. In addition, the accumulation of drugs in skin layers where melanoma cells usually reside were enhanced approximately 10 times with 5-FU and 5 times with DEX when delivering drugs using MSN-NH2 compared to control. MSN-NH2 alone was nontoxic to melanoma cells when incubated for 48 h in the range of 0 to 468 µg/mL. The combination of 5-FU MSN-NH2 and DEX MSN-NH2 showed significant increase in toxicity compared to their free dug counterparts and exhibited a synergetic effect as well as the ability to circumvent DEX induced 5-FU resistance in melanoma cells.

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