The crucial role of solubilization and crystallization steps in the vibrational and optical properties of {Ta6Bri12} cluster core containing systems.

International audienceA general method to generate hybrid hollow capsules is reported. The process is based on the stabilization of solvent droplets by nanoparticles, in macroscopically miscible mixtures of tetrahydrofuran (THF) and water. After addition of a crosslinking polymer and removal of the solvent core, capsules of diameter ca 100 nm are obtained. This novel strategy does not require the use of block copolymers. In contrast, most methods reporting the formation of hybrid nanocapsules incorporate nanoparticles into block-copolymer polymersomes or use nanoparticles tethered with block-copolymers. The nanocapsules were characterized using a full set of techniques including nanoparticle tracking analysis, electron microscopy and liquid phase atomic force microscopy. Our results show that the vesicular shape of the nanocapsules is templated by the liquid droplets. Nanocapsules were prepared from quantum dots, gold nanoparticles, superparamagnetic iron oxide nanoparticles and mixtures of particles. The entrapment of a fluorescent dye was also demonstrated. Thus, nanocapsules with dual properties (e.g., magnetic and fluorescent) are easily obtained. Interestingly, the magnetic nanocapsules enable magnetic resonance imaging contrast enhancement of tumors in vivo

Thin films of polyethyleneimine-stabilized Sb2S3 are prepared via electrophoretic deposition (EPD), showing strong adhesion between deposited layers and underlying substrate, with the films being crystallized via annealing. For amorphous films, thicknesses can be freely tuned from 0.2-1 μm, shrinking to 0.1-0.5 μm when crystallized, whilst retaining a crack-and defect-free surface, thus not impacting on their good stability, and maintaining their optical properties. Through UV-Vis spectroscopy and subsequent modelling of the obtained spectra, it was concluded that the materials after annealing showed a reduced band gap and a demonstrably increased refractive index (n) and carrier concentration. The use of EPD for this material shows the viability of rapidly creating stable thin films of phase-change materials.

Chromophores that generate singlet oxygen ( 1 O 2 ) in water are essential to developing noninvasive disease treatments using photodynamic therapy (PDT). A facile approach for formation of stable colloidal nanoparticles of 1 O 2 photosensitizers, which exhibit aggregation enhanced 1 O 2 generation in water toward applications as PDT agents, is reported. Chromophore encryption within a fuchsonarene macrocyclic scaffold insulates the photosensitizer from aggregation induced deactivation pathways, enabling a higher chromophore density than typical 1 O 2 generating nanoparticles. Aggregation enhanced 1 O 2 generation in water is observed, and variation in molecular structure allows for regulation of the physical properties of the nanoparticles which ultimately affects the 1 O 2 generation. In vitro activity and the ability of the particles to pass through the cell membrane into the cytoplasm is demonstrated using confocal fluorescence microscopy with HeLa cells. Photosensitizer encryption in rigid macrocycles, such as fuchsonarenes, offers new prospects for the production of biocompatible nanoarchitectures for applications involving 1 O 2 generation.

Ultrathin 2D nanoporous materials offer enhanced sensitivity and high spatial resolution in sensing applications making them important for the selective discrimination of guest molecules. Here bottom‐up fabrication is reported of a novel molecularly‐thin nitrogen‐doped 2D fullerphene. Thermal annealing at 700 °C of a bottom‐up assembled fullerene C60‐ethylenediamine (EDA) thin film results in formation of a nitrogen‐doped ultrathin carbon film, fullerphene, which exhibits a hierarchically micro/mesoporous structure at its surfaces. N‐doping of fullerphene is dominated by pyrrolic and quaternary nitrogen atoms, which allow selective and repetitive adsorption and desorption of low‐molecular‐weight carboxylic acid vapors through noncovalent interactions. The large surface area (655.2 m2 g–1) and pore volume (0.659 cc g–1) offered by the hierarchical micro/mesoporous architecture leads to superior sensitivity of fullerphene to formic acid over acetic acid in the vapor phase demonstrating that novel 2D fullerphene provides an attractive platform for the discrimination of carboxylic acids at the single‐carbon‐atom level.

Molybdenum clusters assemble spontaneously into nanocapsules or nanomarbles depending on their solubility in a water/THF mixture.

Nanomaterials with hollow structures are expected to exhibit new functionalities for materials engineering. Here we report the fabrication of fullerene (C60) spheres having different hollow structures by using a kinetically controlled liquid‐liquid interfacial precipitation (KC‐LLIP) method. For this purpose, 1,2‐ethylenediamine (EDA) was used as a covalent cross‐linker of C60 molecules to form C60‐EDA shells, while in‐situ generated EDA‐sulfur (EDA‐S) droplets were applied as ‘yolks’ being eliminated by washing following formation of the yolk‐shell structure, leading to hollow structures. Porous spheres, string hollow spheres, hollow spheres, and open hollow spheres have been synthesized by controlling the kinetics of nucleation of C60‐EDA and the template EDA‐S growth. Isopropanol was used as an additive to control the discrepancy in growth rates of C60‐EDA and EDA‐S. This simple KC‐LLIP preparation method is expected to facilitate the large‐scale fabrication and application of structured C60 spheres in materials science and technology.

Our group recently introduced a new process to synthesize nanoparticle shells of about 100 nm, named "hybridosomes®". Here, the structure and mechanical properties of hybridosomes® made from iron oxide nanoparticles and poly(acrylic acid) are characterized using TEM, AFM and an osmotic compression technique. For the latter, the size distribution of the hybridosomes is monitored by nanoparticle tracking analysis (NTA) in the presence of poly(ethylene glycol)s of different molecular weights. It is found that the size of the hybridosomes® can be tuned from ca. 80 nm to over 110 nm by adjusting the amount of nanoparticles and that their shell consists of a single layer of nanoparticles, with a porous structure. The size of the pores is estimated from osmotic compression experiments at ca. 4000 g mol. The mechanical properties are measured both at the ensemble level using size measurements under osmotic pressure and at the single nanoparticle level by atomic force microscopy nanoindentation. Both osmotic and AFM experiments are analyzed in the framework of the continuum elastic theory of thin shells and yield a value of Young's modulus of the order of MPa.