(286b) Predicting Perturbations to Water Structure By Chemically Heterogeneous Self-Assembled Monolayers to Understand Context-Dependent Hydrophobicity
- Conference: AIChE Annual Meeting
- Year: 2020
- Proceeding: 2020 Virtual AIChE Annual Meeting
- Group: Computational Molecular Science and Engineering Forum
- Time: Tuesday, November 17, 2020 - 8:15am-8:30am
In this study, we utilized classical molecular dynamics (MD) simulations to investigate how amine, amide and hydroxyl functional groups influence the hydrophobicity of mixed SAMs. We used umbrella sampling to directly measure hydrophobic forces between mixed SAMs with compositions that mimic the experiments. Using this technique, we reproduced the qualitative trends of the AFM experiments. We further applied indirect umbrella sampling to measure the hydrophobicity of mixed SAMs with the same functional groups but different surface patterns. We then leveraged the atomistic resolution of MD to relate the changes in hydrophobicity to perturbations in interfacial water structure caused by the specific chemical groups decorating the SAMs. We were able to relate changes in the tetrahedral behavior and hydrogen bond network of the water molecules at the SAM interface to changes of hydrophobicity. This new understanding describing how specific chemical groups perturb interfacial water structure provides important information about how materials tune hydrophobic interactions and could be used to inform the design of new materials.