Surfactants are used for versatile applications, like laundry detergents, personal care products and as new solutions for agricultural applications. However, they are also essential to formulate microemulsions which can serve as templates for nanoparticle materials due to their multifarious structures [1,2]. Up to date, it is not possible to copy the microemulsion-structure to the desired microstructure of polymer particles on a one-to-one scale. Recently Co et al. [3,4] used a new class of highly viscous microemulsions that comprise surfactant, polymerizable oil, and sugar to maintain the microstructure. The addition of sugar enables the kinetics of the phase behavior to be slowed down compared to the changing monomer/polymer ratio during polymerization. In this study we systematically investigated the phase behavior of highly viscous sucrose-microemulsions. Starting from the sugar-free nonionic system H2O – n octane – C10E6 the amount of sucrose within the water phase was increased up to 75%. It is found that the addition of sucrose shifts the phase boundaries to low temperatures. By replacing the surfactant C10E6 by a more hydrophilic surfactant the temperature drop can be compensated. Pure surfactants as well as technical-grade non-ionic surfactants are investigated. Having prepared a highly viscous, polymerizable microemulsion using hexyl and dodecyl methacrylate, we found that the droplet structure is polymerized and depends on the amount of monomer and cross-linker in the oil phase. The structures were investigated by dynamic light scattering and transmission electron microscopy (TEM) and show for the first time that the sizes of the polymeric nanoparticle strongly correlateto the sizes of the microemulsions used. Systematic variations in composition and temperature provide radii between 10 to 50 nm. The polymerized bicontinuous structure is investigated by TEM and scanning electron microscopy.

References

1.M. P. Pileni, Langmuir, 13 (13), 3266 (1997).

2.M. P. Pileni, J. Phys. Chem., 97 (27), 6961 (1993).

3.F. Gao, C.-C. Ho, and C. C. Co, J. Am. Chem. Soc., 126, 12746 (2004).

4.F. Gao, C.-C. Ho, and C. C. Co, Macromolecules, 39, 9467 (2006).