| 초록 |
We have investigated the surface ordering of an amphiphilic asymmetric fan-shaped molecule containing a carboxyl core and fluorinated tails was studied by π-A isotherm, BAM, AFM and TEM. The strong incompatibility between two segments may make stable monolayer and occupy small molecular area compared to the case of conventional dendritic molecules with alkyl chain. Because of fluorinated chains, surface π-A isotherm and BAM measurements show that the molecule forms a dense stable monolayer on a water surface with one phase transition. Atomic force microscopy (AFM) images of the condensed monolayers clearly reveal that the molecules form edge-on-oriented monolayer on the water surface. Upon further compression, the condensed monolayer is transformed into a multilayer, and the irregular islands with terrace morphology appear. The interfacial and internal structure of every terrace shows planar columnar morphology. From these results, we discuss the origin of the surface structure of per-fluorinated self-assembled dendrimers on water surface as well as how to generate terrace morphology at the bulk state, compared with polymeric materials. |
