Search results for "mesoporous"

Functionalization of mesoporous silica nanoparticles through one-pot co-condensation in w/o emulsion

2022

In this work, three different functionalized mesoporous silica nanoparticles (MSNs) were synthesized through the co-condensation synthesis in oil/water emulsion. Hexadecyltrimethoxysilane, triethoxy-3-(2-imidazolin-1-yl)propylsilane and (3-mercaptopropyl)triethoxysilane were used as organo-substituted silica precursors with variable molar ratio with respect to tetraethylorthosilicate (TEOS, 1:4, 1:9, 1:19). The occurred functionalization was investigated by Infrared Spectroscopy and FT-Raman and 29Si {1H} CP-MAS-NMR spectroscopy. Results show that the three materials were successfully functionalized. The influence of the different pendant groups and their concentration on the mesostructured…

Generalized “one-pot” preparative strategy to obtain highly functionalized silica-based mesoporous spherical particles

2022

In this work we present a synthesis strategy for the preparation of Stöber-type mesoporous particles functionalized with inorganic species. The procedure is based on a combination of the Atrane and the Stöber methods. Both as a source of silicon and of the incorporated heteroelements (Fe, Zn, Al, Ti) the corresponding atrane complexes are used as hydrolytic reagents. These complexes are easily formed by reaction with triethanolamine. Mesoporosity is achieved using surfactant micelles as templates. Obtaining uniform spherical particles is achieved by optimizing the amount of water-ethanol in the reaction medium. The particle sizes have been modulated by controlling simple parameters such as …

Biocompatibility and internalization assessment of bare and functionalised mesoporous silica nanoparticles

2021

[EN] We report herein an evaluation of the effect of several mesoporous silica nanoparticles (MSNs) on the cellular uptake and in vitro cytotoxicity in human cells. Bare MSNs and MSNs functionalized with polyethylene glycol or hyaluronic acid are employed to evaluate uptake efficiency and mechanisms of endocytosis in cancer (MDA-MB-231) and non-cancer (MCF10A) cells. Moreover, changes in viability, cell cycle, oxidative stress, and mitochondrial membrane potential are evaluated. Our results confirm that MSNs are internalized efficiently by human cells and that uptake mechanisms differ for cell types and particles. We also confirm that MSNs are biocompatible materials that do not induce ROS/…

Frontispiece: Self-Immolative Linkers as Caps for the Design of Gated Silica Mesoporous Supports

2016

Electrochemistry of Mesoporous Organosilica of MCM-41 Type Containing 4,4′-Bipyridinium Units: Voltammetric Response and Electrocatalytic Effect on 1…

2003

The electrochemistry of a novel organic−inorganic material in which 4,4‘-bipyridinium units (BP) are covalently attached to the walls of a periodic mesoporous organisilica (PMO) of the MCM-41 type is described. The pristine material (BP@PMO), having its internal space completely filled by the cetyltrimethylammonium structure-directing agent, is almost electrochemically silent. In contrast, the extracted material obtained after removal of the structure-directing agent (BP@PMO-ex) exhibits two reduction peaks at −0.36 and −0.75 V vs AgCl/Ag in contact with aqueous electrolytes. BP@PMO-ex shows a remarkable electrocatalytic effect on the oxidation of 1,4-dihydrobenzoquinone (H2Q) that is studi…

Chromogenic Discrimination of Primary Aliphatic Amines in Water with Functionalized Mesoporous Silica

2004

Ordered mesoporous materials: composition and topology control through chemistry

2001

Abstract The atrane route constitutes a very versatile technique to obtain ordered mesoporous materials. A wide diversity of silica and silica-doped materials can be prepared by bringing into play fundamental synthesis parameters (like temperature, concentration and pH) which, in turn, allow modulation of the resulting material topology.

Effect of preparation method on the properties of poly(methyl methacrylate)/mesoporous silica composites

2019

The preparation method of a polymer composite and the filler loading are amongst the factors that influence the properties of the final composites. This article studies the effect of these factors on the thermal stability and thermal degradation kinetics of poly(methyl methacrylate) (PMMA)/mesoporous silica (MCM-41) composites filled with small amounts of MCM-41. The PMMA/MCM-41 composites were prepared through in situ polymerisation and melt mixing methods, with MCM-41 loadings of 0.1, 0.3, and 0.5 wt.%. The presence of MCM-41 increased the thermal stability of PMMA/MCM-41 composites prepared by melt mixing, but in the case of the in situ polymerised samples, the MCM-41 accelerated the deg…

Use of Silica Based Materials as Modulators of the Lipase Catalyzed Hydrolysis of Fats under Simulated Duodenal Conditions

2020

[EN] The effect of silica materials and their functionalization in the lipase catalyzed fat hydrolysis has been scarcely studied. Fifteen silica materials were prepared and their effect on the fat hydrolysis was measured, under simulated duodenal conditions, using the pH-stat method. The materials are composed of the combination of three supports (Stober massive silica nanoparticles, Stober mesoporous nanoparticles and UVM-7) and four surface functionalizations (methyl, trimethyl, propyl and octyl). In addition, the non-functionalized materials were tested. The functional groups were selected to offer a hydrophobic character to the material improving the interaction with the fat globules an…

Catalytic and photocatalytic epoxidation of limonene: Using mesoporous silica nanoparticles as functional support for a Janus-like approach

2020

Abstract Mesoporous silica nanoparticles (MSN) were used as a platform to design novel active materials for the catalytic and photocatalytic epoxidation of limonene. Binary systems comprised of TiO2 and MSN were used for the catalytic reaction when doped with manganese, and for the photocatalytic reaction when functionalised with hexadecyl chains or imidazolinyl groups. All of the MSN based systems were synthesized by condensation in emulsion. A thorough characterization of the powders has been performed by means of Inductively Coupled Plasma – Optical Emission Spectroscopy (ICP-OES), X-ray diffraction (XRD), FT-IR, Raman and EPR Spectroscopy, Fluorescence and diffuse reflectance UV–vis (DR…