(193y) Investigating the Impacts of Microdomain Morphology on Reverse Micelle Mobility within Organogels

Organogels loaded with reverse micelles have potential for use in transdermal drug delivery applications. The mobile reverse micelles act as payload aggregates for the encapsulation and transport of hydrophilic drug molecules. For such an application, characterization and control of the mobility of the reverse micelles is critical. In this work the organogel is comprised of a selectively solvated poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) triblock copolymer network and the mobile micelles of an amphiphilic surfactant (AOT) capable of forming spherical revere micelles. Transport of reverse micelles within a gel network is a complex process in which the mobility of the micelles is hindered by the tortuosity and hydrodynamic drag of the network. The extent of these effects are primarily dependent on the structural geometry of the system, which can be tuned by changes to the molecular parameters and composition of the network forming components. To illustrate the role of microdomain geometry for diffusion in gels, pulsed field gradient nuclear magnetic resonance (PFG-NMR) and bulk elution methods are employed for organogels of varying molecular parameters. These techniques probe mobility over different length scales providing comprehensive insight into the impact of morphology on diffusion. Correlating structure and morphology with transport behavior in reverse micelle loaded organogels will help to inform the development and design of such systems for drug delivery applications.