CHED 339 |
| Understanding how surface structure of self-assembled monolayers (SAMs) change due to the various environments to which they are exposed can lead to the design of better SAMs for industrial uses. This study investigates the structural changes of an acid terminated alkanethiol, 3-mercaptopropionc acid (3-MPA), on Au (111) in various aqueous pH environments using in situ scanning tunneling microscopy. Evidence from previous studies indicate that in a low pH environment the Au vacancy islands exhibit a characteristic crater depth consistent with the thickness of 3-MPA on Au(111). We observed at high pHs the structure of the SAM undergoes significant structural changes. In theory, in low pH environments it is expected that the majority of the 3-MPA terminal groups are protonated leading to hydrogen bonding. In high pH environments the majority of the terminal groups are expected to be deprotonated and thus negatively charged leading to repulsive interactions. This evidence leads to the conclusions that there is a connection between the structure of the SAM and the pH of the environment to which it is exposed. |
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Undergraduate Research Poster Session: Nanotechnology
11:00 AM-1:00 PM, Monday, April 7, 2008 Morial Convention Center -- Hall A, Poster
Division of Chemical Education |