acase@tulane.edu / Self-assembly driven by the hydrophobic effect is the fascinating phenomenon by which non-polar moieties in aqueous solution form unique structures. Perhaps the best known of these assembly processes is the creation of a micelle in water, where hydrophobic tail groups are forced inward while hydrophilic head groups are attracted to aqueous solvent. Beyond micellization, the hydrophobic effect has a strong effect on supramolecular assemblies where guest and host are driven together through the hydrophobic effect. One such supramolecular host is the deep cavity cavitand Octa-Acid (OA), which can encapsulate a hydrophobic guest. This encapsulation has potential applications in drug delivery, chemical catalysis and smart material polymer hydrogel synthesis. Molecular Dynamics simulations (MD) of this system have also been shown to demonstrate the curious phenomenon of cononsolvency, where addition of organic co- solvent causes non-monotonic changes in thermodynamic trends. Cononsolvency has been studied most notably in the literature through examining poly(n- isopropylacrylamide) (PNIPAM), which features a coil-globule-coil transition as methanol is added to aqueous solution. While current research into cononsolvency centers on structural characteristics of the solute, this research focuses on cononsolvency driving effects of the solvent itself by focusing on attributes such as the speed of sound in mixed solutions, the partial molar volume of a co-solvent and the excess chemical potential of argon in solvent mixtures. A solvent-based approach to understanding cononsolvency can reveal trends applicable to all systems, not simply characteristics of one system at a time. Through this research, we uncover structural signatures correlating with cononsolvency. These new insights not only give a more thorough understanding of hydrophobic guest-host assembly, but into the hydrophobic effect and the nature of solvation. / 1 / Alexander Saltzman