| This thesis contains some of the most recent research topics on polydiacetylenes (PDAs) and phthalocyanines (Pcs). Multilayers of the polymerized bis-(p-toluene sulphonate) of 2,4-hexadiyne-1,6-diol (PTS) were fabricated using the Langmuir-Blodgett (LB) technique, and it was found that there is isotherm curve which is similar to that of stearic acid. PTS LB thin films' topography and morphology were studied by atomic force microscopy (AFM) and scanning electron microscope (SEM), and the optical anisotropy of PTS LB thin films was evaluated by the polarized UV/Vis spectroscope. The resulting PTS LB thin film had an anisotropic orientation and their crystal domain sizes were approximately several square microns.; Micron, submicron, and nano sized crystals of PDAs of bis(ethyl)-urethanes of 5,7-dodecadiyne-1,12-diol (ETCD), bis(n-propylurethane)-5,7-dodecadiyne-1,12-diol (PUDO) were fabricated via reprecipitation followed by ultrasonication method, quenching, surfactant addition and vapor phase processing techniques, respectively. The size and shape of microcrystals were characterized by dynamic light scattering (DLS), SEM, field emission scanning electron microscopy (FESEM), and the transmission electron microscopy (TEM). The PDA crystals' structures were studied by X-ray powder diffraction and electronic diffraction (ED). UV/Vis/NIR spectroscopy, differential scanning calorimetry (DSC), and FT-IR spectrometry are applied to study the related properties. For the first time, it was found that there is an unusual electronic absorption maximum red shifting while poly(ETCD) and poly(PUDO) crystals' size decrease down to micron and smaller scale. It is suggested that red shifting involves the strain increase along the PDAs conjugated main chains.; Threshold solid-state ionization energies determined from ultraviolet photoelectron spectra (UPS) are reported for the thermochromic PDAs from ETCD and PUDO, respectively, and the nonthermochromic PTS at temperatures above and below the thermochromic phase transition. PTS has an ionization energy of 5.66 eV which does not change significantly as the temperature is raised above 140°C. At 25°C, poly(ETCD) and poly(PUDO) have threshold ionization energies of 5.65 eV and 5.51 eV, respectively. The ionization energies of these urethane substituted PDAs increase by approximately 0.34 eV as temperature is raised above 140°C and return to the lower values as temperature is returned to 25°C. The magnitude of the increase in ionization energy on heating to temperatures above the thermochromic transition is very close to the shift in energy of the electronic spectrum over the same temperature range. These observations suggest that the structural changes that take place in the course of the thermochromic transition are primarily associated with the valence band and are consistent with partial relief of mechanical strains.; Micro- and nanosized crystals of 1, 4, 8, 11, 15, 18, 22, 25--octabutoxy--29H, 31H--phthalocyanine (Pc) were successfully fabricated through the reprecipitation approach followed by ultrasonication treatment from acetone solution. Phthalocyanine thin films were prepared by vacuum sublimation, spin-coating and drop cast methods, respectively. FESEM, UV/Vis/NIR spectroscopy, polarizing optical microscopy and luminescence spectrometer were applied to study phthalocyanine crystal's surface morphology, electronic absorption, birefringence and light emission properties accordingly. The electronic absorption maximum of Pc nanocrystals shifts to longer wavelength compared to that in acetone solution. Birefringence phenomena exist for Pc crystals with different sizes. Fluorescence is observed for both the Pc in acetone solution and thin film. |
