Assessing the Impact of Block-Selective Homopolymers on the Diffusion of Payloads Through Polymeric Gels
The goal of this project is to investigate the impact of a gel-miscible polymer additive on gel nanostructure, gel mechanical behavior, and sodium bis(2-ethylhexyl) sulfosuccinate (AOT) release rate. Characterizing gels’ mechanical behavior and release of AOT through these gels will benefit future applications like transdermal drug delivery through informed structure-property (i.e., nanostructure-diffusion) relationships. Previous work in our group has shown that gel nanostructure is tuned by varying the amount of gel-forming SEBS copolymer. The purpose of this project is to further investigate methods of gel nanostructure tuning by identifying the impact of a discrete phase-selective polymer on organogel properties. Specifically, the impact of additive polymer concentration of gel nanostructure, mechanical response, and diffusivity will be studied. The current work uses Fourier-transform infrared spectroscopy (FTIR) to track changes in gel AOT concentration over time for gels with ranging homopolymer concentrations. The acquired data is modeled using Fick’s laws to yield a diffusion coefficient for each gel formulation. We hypothesize that the aforementioned nanostructure trends are the culprit for our observation that diffusion of AOT decreases with increasing polystyrene additive polymer concentration. Understanding these relationships will provide key insight for biomedical and agricultural payload delivery applications.