(19a) Atomistic Modeling Approach to Structural Reorganization of Self-Assembled Monolayer On H-Si (111) Surface

In this talk, we present our study on amphiphilic self-assembled monolayers (SAM) on Si (111) surface which has the capability of adapting its configuration to minimize the interfacial tension for both hydrophilic and hydrophobic solvent. To simulate such amphiphilicity of SAM, we attached Y-shaped amphiphilic molecules on Si (111) surface through covalent bonds and then equilibrated the systems in the presence or absence of solvent molecules using molecular dynamics simulations. From these simulations, we found that indeed, the amphiphilic molecules attached on the Si (111) surface reorganize themselves depending on the solvent condition. This structural reorganization was also confirmed from the corresponding change of interfacial tension calculated by Kirkwood-Buff theory. We believe the importance of this study is not only because of its promising potential for various technological applications but also because of fundamental knowledge on molecular interface regarding to how it reorganizes its configuration as a function of hydrophobicity/hydrophilicity of solvent.