EPITAXIAL-GROWTH OF DIACETYLENE VAPOR-DEPOSITION FILM ON AN ORIENTED LANGMUIR MONOLAYER

Polydiacetylene thin films are prepared by vapor deposition of diacetylene monomer on the oriented polydiacetylene Langmuir monolayer and by photopolymerization. Structural and morphological investigations of the polydiacetylene thin film are carried out by using polarized absorption spectroscopy, X-ray diffraction, and optical and electron microscopy. As this is distinct from random-oriented polydiacetylene thin film on the glass substrate treated hydrophobically, there is evidence of uniaxial oriented overgrowth "epitaxy", i.e., the pi-conjugated backbone of the overgrown polydiacetylene thin film is aligned in the same direction as that of the underlying oriented polydiacetylene monolayer. Epitaxial growth in the present case is thought to result from two-dimensional lattice matching.