Abstract
Free radical polymerization of divinyl benzene (DVB) and styrene (St) was performed within reverse hexagonal phases of the anionic surfactant bis(2-ethylhexyl) sulfosuccinate sodium salt (AOT). The morphologies before and after polymerization were studied by small-angle X-ray scattering (SAXS), polarized light microscopy, and scanning and transmission electron microscopy. Polarized light microscopy and SAXS show no significant changes in textures and order during polymerization. A detailed investigation of the polymer matrix after polymerization and removal of the template reveals the formation of regular micrometersized layerlike morphologies. The polymer layers have a hierarchical structure, as they consist of aligned strings of polymer beads with diameters of about 100 nm. Structure formation is directed by the lyotropic phase during polymerization-induced phase separation on a nanometer scale. A mechanism of morphosynthesis is discussed on the basis of characteristic distortions within liquid crystals that are induced by the polymer phase. Parameters such as cross-linking degree and initiator or monomer concentration have a strong influence on the morphologies formed due to a kinetically controlled nucleation and growth mechanism. Finally, the structures formed by polymerization within reverse hexagonal phases are compared to those obtained from lamellar phases of the same surfactant.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 708-713 |
| Number of pages | 6 |
| Journal | Chemistry of Materials |
| Volume | 15 |
| Issue number | 3 |
| DOIs | |
| State | Published - Feb 11 2003 |