Investigation of the C16(EO)10/decane/water system for the design of porous silica materials

We have investigated the phase behavior of the C16(EO)10/decane/water system. Micellar phase (L1), direct hexagonal (H1), cubic (I1) and lamellar liquid crystals were identified. Phase behavior proved that only a weak fraction of oil can be incorporated into the hydrophobic core of micelles (L1). Results also show that whatever the liquid crystal phases both the swelling and the penetration effects take place upon addition of decane. Moreover, at high oil amount, oil-in-water emulsions are formulated. The stability of the emulsion is enhanced from few hours to several months with the addition of oil. ng from this system, porous silica materials were then synthesized. The present work shows that as long as the decane loading is lower than 7 wt.%, decane is an effective expander to enlarge the pore size of mesoporous materials obtained through a CTM-type mechanism. The pore size expansion occurs via the swelling of the surfactant-silica hybrid mesophase. If the concentration of oil is further increased no mesoporous material is recovered anymore, but hollow silica spheres, templated by the oil droplet, are obtained. However, if the amount of oil is too high (>70 wt.%) the structure of the hollow spheres collapses and only their fingerprints is still observed.