Emulsions containing 95 wt.% water were prepared of a fragrance oil (limonene, the mixture of limonene and phenethyl alcohol in different ratios, and benzaldehyde), using a commercial tetraethyleneglycol lauryl ether (Laureth 4) as the stabilizer. The emulsion stability was observed both visually and with the aid of a microscope. The variation of emulsion stability with the fragrance/surfactant ratio is related to the phase changes in the system.

In this study, chitosan (CS)-sodium sodium tripolyphosphate (STPP) (CS-STPP) nanoparticles were fabricated via reverse microemulsion-ionic gelation method. A series of experiments were conducted to optimize the constitution of reverse microemulsion system and the obtained CS-STPP nanoparticles were then characterized by Fourier transform infrared spectrum (FT-IR) and scanning electron microscope (SEM). The concentration of Tween-80 and Span-80 were 6% and 2% respectively when the ratio of water phase to oil phase was 1/7. A narrow size distribution and good dispersion of the obtained CS-STPP nanoparticles were obtained when the stirring speed was 400 rpm/min, with diameter being 552 ± 14 nm. The FT-IR results for the CS-STPP nanoparticles also indicated that the CS was cross-linked with the STPP. These results are very important for the CS-STPP nanoparticles when used as drug carriers.