Star-Shaped Polymers with Helical Polyacetylene Arms. Comparison of Solution- and Solid-State Properties with Linear Helical Polyacetylenes

Star-shaped polymers have attracted attention due to their unique solution properties and viscosities. These effects are attributed to their hydrodynamic radii that differ significantly from those of linear polymers. The present study reports the synthesis of star-shaped helical polyacetylenes substituted with l-valine- and l-threonine-based optically active groups. The formation of star-shaped polymers was confirmed by size exclusion chromatography, solution viscosity, dynamic light scattering, and small-angle X-ray scattering measurements. The chiroptical intensities of the star-shaped polymers tended to be smaller than those of the corresponding linear polymers in solution but larger in the film state. The water contact angles and refractive indices of the star-shaped polymers were smaller than those of the linear polymers.