Interfacial Langmuir-Blodgett assembly of straight and parallel aligned nanoribbons

The fabrication of one-dimensional nanomaterials is currently an important issue in nanoscience and nanotechnology. Herein, we report the construction of long, straight, and parallel aligned nanoribbons, by the in situ assembly of a novel, triangular amphiphilic molecule at an air-water interface. The 1,3,5-trimesyl-tri-L-glutamic acid hexaester, which has an aromatic core with three hydrophilic arms bearing three amide units and ending with six ester groups, was spread on a water surface, forming a stable, ultrathin film with a plateau region in its isotherm. When the film was compressed to a surface pressures, which exceeded the plateau region, nanoribbons were formed. Atomic force microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy, electron diffraction, and circular dichroism were used to characterize the film and the nanoribbons. The nanoribbons were formed due to the in situ transformation of a two-dimensional monolayer into a three-dimensional nanoarchitecture at the air-water interface. When the compound was spread onto the water surface, it first formed a monolayer. Compressing the film led to the overlap of the second layer on the monomolecular sublayer. This second layer formed nanoribbons in which the triangular molecules stood vertically (using two corners) on the sublayer. The nanoribbons were stabilized by the ordered packing of the triangular molecules, which were held together by intermolecular hydrogen bonding. The results present a facile procedure for constructing three-dimensional, regular nanoarchitectures in a two-dimensional environment.