<p>The first two chapters make use of simple, simulated model systems to break down the unique solvation thermodynamics of solutes at the vapor-liquid interface of water and of aggregation processes in the bulk. In particular, attention is paid to the direct solute-solvent energetic and entropic components that dictate the chemical potential. This proves a fruitful approach to understanding the counter-intuitive adsorbtion of ions to the interface. Additionally, the validity of linear response theory is tested in the interfacial region. Further, the contribution of ion surface pinning to the total adsorbtion thermodynamics is explored.</p> <p><br></p> <p>The third chapter studies the solvent-solvent interaction energy in response to changes in solute-solvent interactions. A solvent-solvent coupling scheme is developed to the relationship of solute-solvent interactions and solvent-solvent interactions and allows for more statistically stable access to solvent restructuring energies</p> <p><br></p> <p>The fourth chapter looks at ions of a range of sizes, but with a focus on those smaller than sodium. There smaller cations show a counter-intuitive trend of showing more attraction to the interface, when they are predicted to be more repelled than the larger ions. This is investigated with thermodynamic and hydration structure tools.</p> <p><br></p>