Organogels containing both fixed and mobile micelles comprise multiple unique structures each with a corresponding material property ‘responsibility’. In the present case, the fixed micelles function as network points in a physically-crosslinked system and therefore provide gels their physical state and mechanical properties. They are composed of symmetric triblock copolymers wherein the molecular weight and composition are important considerations. The mobile micelles, which have the potential to diffuse within and elute from the gels, provide a mass transport characteristic. These micelles are composed of amphiphilic surfactants capable of forming reverse micelles (i.e., micelle formation in nonpolar solvent) of relatively small size. The organogels also, by definition, include a nonpolar organic solvent with low-volatility. Finally, the preparation of dual (fixed and mobile) micelle organogels via solvent casting requires the use of a fourth component, the casting solvent, which must solubilize the gel components and have sufficiently high vapor pressure. The chemical identity of the casting solvent also has important implications on the final structure of gels. Here, we will discuss specific materials selection and processing considerations for the fabrication of fixed/mobile micelle organogels and consequential gel properties such as optical clarity, physical state (i.e., gel vs. fluid), and mechanical behavior. Successful creation and understanding of dual micelle organogels will enable them to be implemented in applications such as transdermal drug delivery where the fixed micelles hold products in their desired shape/size and the mobile micelles transport therapeutics to the skin.

Fabrication of organogels containing fixed and mobile micelles

255th National Meeting (2018)

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