Phase Transition of Layer Structure of Poly(1,4-benzenedithiol-co-l,4-diethynylbenzene) by Photon Mode

The effect of light wavelength on the phase transition of the layer structure of poly(1,4-benzenedithiol-co-1,4-diethynylbenzene) was studied under an air atmosphere at 18-22 degrees C. The thin layer polymer crystals were prepared by solid state polymerization, and the amount of the layer structure was evaluated by an X-ray diagram. A monochromatic light with a wavelength in the region of ca. 500-600 nm was used as a light source. The amount of the layer structure was found to be altered by light. There were three characteristic wavelengths at 545.6, 567.8 and 590.1 nm, inducing pronounced peak intensities in the X-ray diagram. On the other hand, at 501.1, 539.6, 571.8 and 588.1 nm the light made the peak intensity decrease steeply. The phase transition was induced by a photon mode, but not by a heat mode. The amount of the layer structure was altered linearly with increasing irradiation time up to 60 min. However, over 60 min the change became dull. The total energy given to the polymers during the irradiation was about 24 x 10(-3) J / cm(2). Accordingly, the phase transition occurs with a high sensitivity to the light. The polymers were irradiated alternately by the light of 545.6 nm and 571.8 nm at intervals of 60 min, respectively. The amount of the layer structure was controlled reversibly by the light.