| 초록 |
Langmuir monolayers are the best model system to study phenomena on the 2-D domain. There were so many studies for metal adsorption to Langmuir monolayers with FTIR. In this study, fatty acid Langmuir monolayers at the air/water interface were investigated both by an in-situ near-normal external reflection and by an ex-situ transmission FTIR methods. The monolayers consist of reactive fatty acids and nonreactive fatty alcohols to cadmium ions requiring 2:1 covalent complexation. The in-situ method revealed that ion adsorption was significantly less than full coverage relative to available reactive moieties in case of the amount of nonreactive ones exceeding 20%. On the contrary, the ex-situ method showed nearly full coverage of cadmium adsorption regardless of the monolayers' composition. This discrepancy occurs most probably because the ex-situ analyses requires the sampled monolayers to be neutralized upon drying by an additional adsorption of cadmium ions, which does not reflect the state of the monolayer at the air/water interface. Therefore, we can conclude that in-situ analyses is necessary to investigate the heterogeneous effect of surface reaction. |
