Rheological Properties of Self-Assembled Monolayers Formed by Modified Oligo(ethylene oxide) Molecules using a Quartz Crystal Microbalance.

Investigating the relationship betw een molecular structure and the physical properties of self-assembled monolayers (SAMs) is essential for developing strategies to prevent nonspecific adsorption. In this study, we used a quartz crystal microbalance to examine this relationship from a rheological perspective, focusing on SAMs formed from oligo(ethylene oxide) molecules in which a single oxygen atom was substituted with either carbon or nitrogen. The results showed that replacing one oxygen atom with carbon increased the shear modulus of the SAMs, whereas substitution with nitrogen decreased it. In contrast, the shear viscosity remained unchanged regardless of the type of substitution.