Hybrid gold-silica nanoparticles for plasmonic applications: A comparison study of synthesis methods for increasing gold coverage.

The current work focuses on the synthesis of hybrid nanoparticles (NPs) made of a silica core (Si NPs) coated with discrete gold nanoparticles (Au NPs), which exhibit localized surface plasmon resonance (LSPR) properties. This plasmonic effect is directly related to the nanoparticles size and arrangement. In this paper, we explore a wide range of size for the silica cores (80, 150, 400, and 600 nm) and for the gold NPs (8, 10, and 30 nm).

Study of the aggregation behavior of Janus particles by coupling experiments and Brownian dynamics simulations.

Hypothesis: New colloids such as inverse patchy particles or Janus particles are considered as smart building blocks in the development of innovative and performant materials. For example, the control of the self-assembly of oxide-based charged Janus particles is interesting for ceramic shaping. Thus, the synthesis of silica based Janus particles as well as a detailed study of their behavior in suspension are presented in this paper.

Brownian dynamics simulations of one-patch inverse patchy particles.

Inverse patchy particles are promising colloids to develop new architectures in ceramic materials based on their self-assembly. Nonetheless, a good understanding of their aggregation is required. Several previous studies have shown that the behavior of ceramic colloids can be well described by the DLVO interaction potential.

Role of Electrostatic Interactions in Oil-in-Water Emulsions Stabilized by Heteroaggregation: An Experimental and Simulation Study.

Oil-in-water emulsion stabilization by heteroaggregation of hydrophilic particles without a surfactant is of importance in a wide range of applications; however, the stabilization mechanism is little described. To shed light on the early stage of the stabilization mechanism, a model system composed of an oil wax phase dispersed in water with oppositely charged colloidal particles is studied experimentally and numerically. Experiments show that the colloids do not penetrate deeply in the oil phase, suggesting that adsorption of the colloidal particles on the wax droplets is mainly due to electrostatic interactions.

Influence of different surfactants on Pickering emulsions stabilized by submicronic silica particles.

Hypothesis: Pickering emulsions were prepared using wax and silica submicronic particles (650 nm), as a first step towards the synthesis of Janus particles. Surfactants added to silica particles control the emulsion stability and particles arrangement, i.e.

Synthesis of fluorinated ceramic Janus particles via a Pickering emulsion method.

Hypothesis: Dispersion or aggregation of ceramic nanoparticles in suspension is mainly influenced by their surface properties. The preparation of hydrophobic/hydrophilic nanoparticles was studied by synthesizing for the first time fluorinated Janus particles via a Pickering emulsion method.

Experiments: Fluorinated silica Janus particles were synthesized with a "grafting to" method using silica/wax emulsions.

Contribution of aggregation to the growth mechanism of seeded calcium carbonate precipitation in the presence of polyacrylic acid.

Our work investigates the precipitation mechanism of a seeded calcium carbonate reaction, by using cryogenic TEM to observe the early stages of the reaction. The early precipitation of a hydrated phase is proposed as an intermediate phase before transformation into calcite. Thermodynamic modeling in conjunction with pH, surface potential measurements, and colloidal stability modeling demonstrate that calcite growth is dominated by agglomeration.