Charge Inversion at the Surface by Adsorption of Trivalent Cations on Langmuir Monolayer

Infrared-visible sum-frequency generation spectroscopy was used to study cation adsorption and charge inversion behavior at the lipid/water interface of dimyristoylphosphatidic acid (DMPA) monolayer. The alignment of interfacial water molecules was inferred by electric field produced from the adsorbed surface charges at the lipid/water interface, which suggested charge inversion behavior.