| Hydrotropes are amphiphilic molecules with hydrophobic portions too small to form micelles. Hydrotropes bind strongly to surfactant micelles, and can facilitate the formation of interesting microstructures such as elongated micelles and vesicles. The utilization of these microstructures as templates is an attractive approach for the synthesis of organic materials with well-defined morphologies and length scales. However, changes to solution conditions disrupt these structures, which limits their use in applications. Polymerization can create robust replicas of these microstructures with increased mechanical strength and stability under a variety of conditions.; In this dissertation, the formation and templating of vesicles and worm-like micelles comprised of polymerizable surfactants and hydrotropes are investigated. The use of polymerizable species allows for the production of stable structures directly from the template. Vesicles can be formed spontaneously (in the absence of shear) in mixtures of oppositely charged species. Light scattering and small-angle neutron scattering (SANS), along with direct images from cryogenic transmission electron microscopy (cryo-TEM), allowed us to quantify and confirm that the vesicle dimensions were essentially unchanged during polymerization. Conversely, the micelles elongated during the course of the reaction, although their cross-sectional radius remained unchanged. This elongation likely results from the interplay of the micelle dynamics and the degree of reactivity of the polymerizable group.; The use of water-soluble free radical initiators for these studies led to the discovery of the spontaneous formation of vesicles in mixtures of the initiator with sodium dodecylbenzenesulfonate (SDBS) surfactant alone, in the absence of polymerization. A micelle to vesicle transition was observed with increasing amount of initiator, and the characterization of these mixtures indicated that at least some initiators behave as hydrotropes. Likewise, basic amino acids displayed hydrotropic behavior. For certain values of pH, vesicles formed spontaneously in mixtures of SDBS with histidine, arginine, or lysine. On the other hand, mixtures of lysine and alkyl sulfate surfactants led to the formation of thermo reversible gels. These gels were made of fibrillar networks that were also responsive to changes on pH. |
