초록 |
Monosubstituted polyacetylenes having a very high stereoregularity can be obtained through the polymerization with rhodium-based transition metal catalyst. Among them, poly(N-propargylamide)s are known to maintain a very stable cis-transoid helical structure in a solution by intramolecular hydrogen bonding between the side chain amide groups. Previously, in our laboratory, the intramolecular hydrogen bonding of a monosubstituted poly(phenylacetylene) having the similar helical-spring structure has been precisely controlled in solution state by solvent and temperature, and the polymer showed a reversible helix-coil phase transition accompanied with significant changes of color and viscosity. In a similar way, poly(N-propargylamide)s were also examined in this study for the effects of solvent and temperature on the phase transition on the basis of the ultraviolet-visible absorption and circular dichroism spectroscopies, and the results were discussed from the thermodynamic perspectives. |