The effect of photopolymerization on the structure, stability and encapsulation properties of polydiacetylene micelles containing nitrilotriacetic acid head groups are investigated. Micellar nanostructures of 7–10 nm diameter are identified that are invariant after polymerization. In the micelles, the polymerized ene‐yne chains are much shorter than in planar lipid membranes. SANS confirmed the presence of a monodisperse population of small particles before and after polymerization. It is shown that the CMC decreases manifold after micelle photopolymerization, indicating that it stabilizes the micellar structure. After photopolymerization, these micelles preserved their strong ability to solubilize a hydrophobic pigment, which makes them potentially interesting as drug delivery vehicles. magnified image

The effect of fumed silica particles on water-in-crude oil emulsions was analyzed by stability tests, interfacial tension measurements, dilatational rheology of the interface, rheology of the particles dispersions, and Cryo-SEM analysis. The crude oil studied is a paraffinic one and was separated by distillation in three fractions containing mainly saturate, aromatic, and resin compounds. The stability of emulsions formed from these oil fractions was also studied with or without silica particles. Experiments without particles performed with oil or its fractions underline that the most stable emulsion is formed with the heavy fraction which corresponds to the highest elastic modulus of the interface. Different mechanisms of emulsion stability in the presence of particles were discussed according to the particle wettability. Whatever the oil phase composition, it is obviously noticed that hydrophilic particles destabilize water-in-oil emulsions, whereas hydrophobic particles stabilize them. For hydrophilic particles, the ″solid-like″ behavior of the interfacial film revealed by the high value of the elastic modulus, IFT measurements and the observations by Cryo-SEM, supports the presence of A200 particles at the oil/water interface. The highest stability of the emulsions in the presence of hydrophobic particles results from the addition of several effects: the tendency to form a structured organization in the oil continuous phase and the influence of the attached particles at the interface. This study underlined that no direct relation is observed between the stability of water-in-oil petroleum emulsions and the interfacial tension measurements particularly in the presence of particles. Otherwise the viscoelastic measurements by the dilatational drop technique corroborate the relation between a high emulsion stability and a high viscoelastic modulus in the case of emulsions without particles. In the presence of particles, the elastic behavior of the interface is less affected by the hydrophobic than by the hydrophilic particles.

A series of polydiacetylene (PDA) - based micelles were prepared from diacetylenic surfactant bearing polyethylene glycol, by increasing UV-irradiation times. These polymeric lipid micelles were analyzed by physicochemical methods, electron microscopy and NMR analysis. Cellular delivery of fluorescent dye suggests that adjusting the polymerization state is vital to reach the full in vitro potential of PDA-based delivery systems.