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Polymeric micro- and nanoparticles receive the attention of researchers in different areas such as drug delivery, sensing, imaging, cosmetics, diagnostics, and biotechnology. However, processes with conventional equipment do not always allow precise control of their morphology, size, size distribution, and composition. On the other hand, microreaction technology offers improved control over the hydrodynamics, mass and heat transfer, allowing production of polymeric particles with better defined or new characteristics. Thus new horizons in polymer particle engineering arise from the use of microstructured or microfluidic devices. This article gives an insight into the latest developments and trends in the production of polymeric micro- and nanoparticles realized by microreaction technology directly.

Prolonged periodical variations of the surface density of a film of phospholipids adsorbed on the surface of an air bubble and in contact with a dispersion of phospholipid vesicles (orange) lead to accelerated phospholipid adsorption and lowering of the interfacial tension. The phenomenon is assigned to a coupling between the periodical variation of the surface density of the phospholipid at the interface and its dilute‐to‐condensed (LE‐to‐LC) phase transition.

A novel device is applied to produce emulsions of methyl methacrylate in water with a controllable size in the range of 30–100 nm. The process is based on the reciprocating flow of the material through an abrupt contraction which generates a strong elongational flow. This results in highly efficient dispersive mixing even at moderate pressures, thus reducing viscous dissipation and improving temperature control. The original design of the device also allows easy feeding and sampling, easy adjusting of the total volume of the emulsion, and processing volatile components owing to the liquid- and gas-tightness of the device. The influence of process parameters (like pressure drop and mixing time) and composition of the system (volume ratio of the dispersed and continuous phases, surfactant and hydrophobic agent weight percentages) on the droplet size and stability of the emulsions is investigated and discussed.

ISSN: 1862-832X; International audience; A microplant, starting from monomers to produce polymer particles, is described and integrates polymerization reaction, polymer analysis and nanoparticle formation in a single continuous-flow microprocess. Original contribution is brought by online polymer analysis and inline polymer nanoprecipitation. Multi-detection GPC of samples taken at the outlet of the microreactor actually enables the characterization of linear and branched polymers by combining a concentration- and a mass-sensitive detection technique. When the steady state of the microreactor is reached, micromixer-assisted nanoprecipitation of the polymer solution follows, leading to a colloidal suspension of nanoparticles with a narrow particle size distribution. Particle sizes, around 100?nm, can be tuned by process parameters.

The adsorption dynamics of a series of phospholipids (PLs) at the interface between an aqueous solution or dispersion of the PL and a gas phase containing the nonpolar, nonamphiphilic linear perfluorocarbon perfluorohexane (PFH) was studied by bubble profile analysis tensiometry. The PLs investigated were dioctanoylphosphatidylcholine (DiC(8)-PC), dilaurylphosphatidylcholine, dimyristoylphosphatidylcholine, and dipalmitoylphosphatidylcholine. The gas phase consisted of air or air saturated with PFH. The perfluorocarbon gas was found to have an unexpected, strong effect on both the adsorption rate and the equilibrium interfacial tension (γ(eq)) of the PLs. First, for all of the PLs, and at all concentrations investigated, the γ(eq) values were significantly lower (by up to 10 mN m(-1)) when PFH was present in the gas phase. The efficacy of PFH in decreasing γ(eq) depends on the ability of PLs to form micelles or vesicles in water. For vesicles, it also depends on the gel or fluid state of the membranes. Second, the adsorption rates of all the PLs at the interface (as assessed by the time required for the initial interfacial tension to be reduced by 30%) are significantly accelerated (by up to fivefold) by the presence of PFH for the lower PL concentrations. Both the surface-tension reducing effect and the adsorption rate increasing effect establish that PFH has a strong interaction with the PL monolayer and acts as a cosurfactant at the interface, despite the absence of any amphiphilic character. Fitting the adsorption profiles of DiC(8)-PC at the PFH-saturated air/aqueous solution interface with the modified Frumkin model indicated that the PFH molecule lay horizontally at the interface.

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Petroselinic (cis-6 18:1) and oleic (cis-9 18:1) acids that occur together in Umbelliferae seeds can be resolved by gasliquid chromatography (GLC) of their methyl or isopropyl esters on a 50 m × 0.25 mm fused-silica capillary column coated with a 100% cyanopropyl polysiloxane stationary phase (CP Sil 88). The use of isopropyl esters instead of methyl esters increases the difference between equivalent chainlengths from 0.06 carbon unit up to 0.08. This is sufficient to obtain an almost base-line resolution between the two components.cis-Vaccenic acid is completely separated from oleic acid in both derivative forms. GLC of fatty acid isopropyl esters on an appropriate capillary column thus appears to be the simplest means to simultaneously and accurately quantitate petroselinic, oleic andcis-vaccenic acids.