Toward Distinguishing between the Superchaotropic and Hydrophobic Characters of Nanometric-Sized Ions in Interaction with PEGylated Surfaces.

In this study, we explore the superchaotropic effect of various polyoxometalate or boron cluster nano-ions on hydrophilic neutral surfaces. Nano-ions, characterized by low charge densities, exhibit strong adsorption on non-ionic hydrophilic surfaces like PEGylated micelles. This adsorption phenomenon was attributed to the enthalpically favorable dehydration of nano-ions, the so-called superchaotropic effect.

Mesoporous organosilicas with thiol functionalised pores: multifunctional dendrimers as sacrificial building block and template.

The synthesis of multifunctional poly(amidoamine) (PAMAM)-based dendrimers containing a cleavable disulfide linker within each arm of the dendrimer, together with condensable triethoxysilyl groups on the periphery of the dendrimer, is described. The dendrimers were mixed with 1,4-bis(triethoxysilyl)benzene and subsequently transformed into silsesquioxane gels or periodic mesoporous organosilicas (PMOs) to generate materials with dendrimers covalently embedded within the interior of the silsesquioxane networks. Subsequent treatment of the gels with dithiothreitol enabled the core of the dendrimers to be selectively cleaved at the disulfide site, thus generating thiol functions localised within the pores.

Large-Pore Periodic Mesoporous Organosilicas as Advanced Bactericide Platforms.

Despite the versatility of periodic mesoporous organosilicas (PMOs), the bactericide capacity of these hybrid platforms has seldom been explored. Herein, we describe the synthesis of large-pore phenylene-bridged PMOs, mesostructured by polyion complex (PIC) micelles (PICPMOs) incorporating an antibiotic, neomycin B. A key feature of this approach is that the bioactive molecules are directly encapsulated within the PICPMOs during their formation.

Sorption pH dependance of strontium/calcium by sodium nonatitanate.

Sodium nonatitanate powder is a layered material containing some potential exchangeable sodium ions between layers. In this work, sorption mechanism of this material has been studied and modeled at the solid-liquid interface. In particular, the ion-exchange mechanism is up to now not entirely known and especially the role of the pH on sorption properties.

Novel Highly Luminescent Amine-Functionalized Bridged Silsesquioxanes.

Amine-functionalized bridged silsesquioxanes (BSs) were synthesized from bis[(3-trimethoxysilyl)propyl] amine via a solvent-mediated route. BS-1 and BS-2 were obtained at neutral pH with sub- and stoichiometric amounts of water, respectively, and high tetrahydrofuran content. BS-3 was prepared with hyperstoichiometric water concentration, high tetrahydrofuran content, and hydrochloric acid.

Strontium selectivity in sodium nonatitanate Na ₄Ti₉O₂₀·xH₂O.

We study the extraction of strontium by sodium nonatitanate powder from nitrate strontium and acetate sodium mixture. Experiments show that adsorption is quantitative. The excess Gibbs free energy has been modeled by various models (ideal, 2D Coulomb, regular solution model) for the solid phase.

Tailoring the hydrophilic/lipophilic balance of clickable mesoporous organosilicas by the copper-catalyzed azide-alkyne cycloaddition click-functionalization.

We have designed and synthesized a clickable bridged silsesquioxane material featuring pendant alkyne chains as an aggregate of golf-ball-like nanoparticles, as evidenced by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and small- and wide-angle X-ray scattering (SWAXS). Using the copper-catalyzed azide-alkyne cycloaddition reaction with a range of organic azides of variable characteristics, we transformed this parent bridged silsesquioxane into new materials with tunable hydrophilic/lipophilic balance in high conversions while preserving the original morphology. N2, cyclohexane, and water sorption experiments were used to quantify the affinity of these materials toward the sorbates through the determination of their Henry's constants.

A general method for preparing bridged organosilanes with pendant functional groups and functional mesoporous organosilicas.

New organosilica precursors containing two triethoxysilyl groups suitable for the organosilica material formation through the sol-gel process were designed and synthesised. These precursors display alkyne or azide groups for attaching targeted functional groups by copper-catalysed azide-alkyne cycloaddition (CuAAC) and can be used for the preparation of functional organosilicas following two strategies: 1) the functional group is first appended by CuAAC under anhydrous conditions, then the functional material is prepared by the sol-gel process; 2) the precursor is first subjected to the sol-gel process, producing porous, clickable bridged silsesquioxanes or periodic mesoporous organosilicas (PMOs), then the desired functional groups are attached by means of CuAAC. Herein, we show the feasibility of both approaches.

Ionic physisorption on bubbles induced by pulsed ultra-sound.

Ion flotation processes involve the use of bubbles in order to separate ionic species from a mixed solution. Due to bubble interfaces we may assume null curvature at the molecular scale, where selective ion adsorption might be more easily investigated than with liquid-liquid extraction. In contrast to a classical flotation set-up, where bubbles are introduced via a glass frit, we use here a controlled sono-device generating cavitation bubbles which are initially absolutely clean.

Colloidal shape controlled by molecular adsorption at liquid crystal interfaces.

The ability to control finely the structure of materials remains a central issue in colloidal science. Due to their elastic properties, liquid crystals (LC) are increasingly used to organize matter at the micrometer scale in soft composites. Textures and shapes of LC droplets are currently controlled by the competition between elasticity and anchoring, hydrodynamic flows, or external fields.

Lyotropic structures in a thermotropic liquid crystal.

We have investigated the nature of didodecyldimethylammonium bromide (DDAB)/water aggregates dispersed in 4-n-pentyl-4'-cyanobiphenyl thermotropic liquid crystal (5CB). The structure of this microemulsion has been probed by small-angle neutron and X-ray scattering experiments far above the nematic-to-isotropic phase transition temperature of the solvent. Our data show that the stability of this system is controlled by strong attractive van der Waals interactions between spherical inverted micelles.