Synthesis and Solution Properties of a Rigid Helical Star Polymer: Three-Arm Star Poly(quinoxaline-2,3-diyl)

Six semiflexible helical three-arm
star poly­[5,8-dimethyl-6,7-bis­(propoxy­methyl)­quinoxaline-2,3-diyl]
(A3PQ) samples which have different arm lengths ranging in the weight-average
molar mass Mw from 1.5 × 104 to 2.5 × 105 g mol–1 were synthesized
via the living polymerization of the corresponding 1,2-diisocyanobenzene
using a trifunctional palladium initiator. The particle scattering
function P(q), the z-average mean-square radius of gyration ⟨S2⟩z, and the intrinsic
viscosity [η] for the A3PQ samples were determined from light
and small-angle X-ray scattering and viscosity measurements in tetrahydrofuran
at 25 °C. The obtained data were compared with modern theories
for the wormlike star. The experimental P(q) data were represented by the wormlike star model connected
with a universal joint. The other data were comparably explained by
the same model.