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Size-tunable polymeric nanoparticles have been successfully produced by a microfluidic-assisted nanoprecipitation process. A multilamination micromixer has been chosen to fabricate continuously nanoparticles of methacrylic polymers. Various operating conditions, such as the polymer concentration, the amount of non-solvent and the characteristics of the raw polymer (molecular weight and architecture: linear vs. branched) have been investigated. Their influences on the final particle size, ranging from 76 to 217 nm, have been correlated to the mechanisms leading to the formation of nanoparticles. In this type of microfluidic device, mixing mainly operates by diffusion mass transfer, helped by hydrodynamic focusing. The effect of micromixing on the size of particles has also been shown experimentally and supported by a computational fluid dynamics (CFD) study. A mixing criterion has been defined and numerically calculated to corroborate the effect of the flow rate of polymer solution on the particles size. An increase in the polymer solution flow rate increases the value of this mixing criterion, resulting in smaller nanoparticles.

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Organic/inorganic hybrid composite materials with the dispersed phases in sizes down to a few tens of nanometers raised very great interest. In this paper, it is shown that silica/epoxy nanocomposites with a silica content of 6 wt % may be obtained with an “ in situ ” sol–gel procedure starting from two precursors: tetraethyl orthosilicate (TEOS) and 3-aminopropyl-triethoxysilane (APTES). APTES also played the role of a coupling agent. The use of advanced techniques (bright-field high-resolution transmission electron microscopy, HRTEM, and combined small- and wide-angle X-ray scattering (SAXS/WAXS) performed by means of a multirange device Ganesha 300 XL+) allowed us to evidence a multisheet structure of the nanoparticles instead of the gel one typically obtained through a sol–gel route. A mechanism combining in a new manner well-assessed knowledge regarding sol–gel chemistry, emulsion formation, and Ostwald ripening allowed us to give an explanation for the formation of the observed lamellar nanoparticles.