Self-Assembled Supramolecular Architecture of a Bolaamphiphilic Diacid on the Subphases Containing Ag(I) and Eu(III) Metal Ions

The self-assembled supramolecular nanostructures of a bolaamphiphilic diacid, 1,20-octadecanedicarboxylic acid (ODA), on the subphase containing various metal ions have been investigated. Different from the bolaamphiphilic acid on pure water surface, exotic nanostructures were observed for the spreading Langmuir film of ODA on the subphase containing Ag(I) or Eu(III) ions. In the case of the Ag(I) subphase, a stripe morphology was observed, while a disk morphology was observed for a one-layer LB film of ODA deposited from the Eu(III) subphase. All of these architectures consisted of nanodisks with a diameter of 50-70 nm. A series of methods such as atomic force microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectra were used to characterize the deposited Langmuir-Blodgett films. It was suggested that the complex formation between ODA and Ag(I) or Eu(III) caused the selfassembled nanostructure. A possible mechanism for the formation of the reported nanoarchitectures was proposed.