Investigation of the Damage to Hydrophobic Self-Assembled Monolayers by Aqueous Salt Solutions

When water is forced into contact with a hydrophobic surface, a depletion layer, or a low-density region of water, is formed. To study the depletion layer in more natural applications, we look at how aqueous salt solutions interact with hydrophobic surfaces made from self-assembled monolayers (SAMs) of octadecanethiol. In order to investigate this interaction we need smooth, homogeneous SAMs. Aqueous solutions can corrode the SAM, so we experiment salt molarity and cation size to eliminate this problem. The experimental methods include contact angle measurements, scanning electron microscopy, surface plasmon resonance.