Emulsions Stabilized with Alumina-Functionalized Mesoporous Silica Particles.

Alumina-functionalized ordered mesoporous silica SBA-15 particles have been proposed to stabilize Pickering emulsions. Functionalization of SBA-15 particles have been performed by depositing alumina using a two-step synthesis (first, silica condensation, followed by alumina precipitation). Three different Al to Si ratios have been prepared.

Hybrid Core-Shell Nanoparticles by "Plug and Play" Self-Assembly.

Supramolecular hybrid functional nanoparticles (NPs) can be obtained via the colloidal tectonics approach provided that multiple interactive molecular tectons are used. Herein, the programmable synthesis of novel hybrid core-shell nanoparticles via the following sequential steps is reported: (i) complexation of 1-decanol by the β-cyclodextrin (β-CD), (ii) spontaneous self-assembly into CD NPs, (iii) adsorption of polyoxometalate anions, PW O , on the polar neutral interface of the CD NPs. Such an approach paves the way for the design of novel and original materials and systems.

Dense covalent attachment of magnetic iron oxide nanoparticles onto silica particles using a diazonium salt chemistry approach.

We demonstrate that the reaction of amino modified particles with tert-butylnitrite can provide diazonium surface functionality which itself is highly reactive with iron oxide nanoparticles in basic media. Using this strategy we synthesize a magnetic hybrid material with dense covalent attachment of magnetic iron oxide nanoparticles on the silica surface. This simple and versatile functionalization procedure has a wide variety of potential applications in surface science and materials research.

Fine tuning of emission through the engineering of colloidal crystals.

We describe the preparation and characterization of photonic colloidal crystals from silica spheres with incorporated luminescent [Mo(6)Br(14)](2-) cluster units. These structures exhibit strong angle-dependent luminescent properties. The incorporation of one or several planar defects in the periodic structures gives rise to the creation of a passband in the stopband.

Nonaqueous sol-gel chemistry applied to atomic layer deposition: tuning of photonic band gap properties of silica opals.

Combining both electromagnetic simulations and experiments, it is shown that the photonic pseudo band gap (PPBG) exhibited by a silica opal can be fully controlled by Atomic Layer Deposition (ALD) of titania into the pores of the silica spheres constituting the opal. Different types of opals were assembled by the Langmuir-Blodgett technique: homogeneous closed packed structures set up of, respectively, 260 and 285 nm silica spheres, as well as opal heterostructures consisting of a monolayer of 430 nm silica spheres embedded within 10 layers of 280 nm silica spheres. For the stepwise infiltration of the opals with titania, titanium isopropoxide and acetic acid were used as metal and oxygen sources, in accordance with a recently published non-aqueous approach to ALD.

Multiresponsive hybrid microgels and hollow capsules with a layered structure.

Various stimuli-responsive composite particles with a high control of their internal structure and their corresponding hollow capsules are synthesized and characterized by photon correlation spectroscopy, TEM, and AFM. Core-shell particles with a silica core and a thermoresponsive shell are obtained by polymerization of N-isopropylacrylamide (NIPAM) in the presence of silica seeds grafted with a high density of gamma-methacryloxypropyltrimethoxysilane (MPS). The influence of the synthesis conditions is studied.

Pickering emulsions with stimulable particles: from highly- to weakly-covered interfaces.

We study oil-in-water emulsions stabilised by pH-sensitive colloidal silica or latex particles. Depending on the composition of the continuous phase, the same type of particles and the same emulsification process lead to emulsions characterised either by large drops densely covered by the particles, or to small droplets which are weakly covered. The two kinetically stable states can be tuned reversibly by using pH or salinity as compositional stimuli.