A Helical Poly(macromonomer) Consisting of a Polyacetylene Main Chain and Polystyrene Side Chains

A novel helical poly(macromonomer) [poly(M‐PS): absolute $\overline M _{\rm w} $  = 82 800–252 000, determined by GPC/RALLS] with a polyacetylene main chain and polystyrene (PS) side chains was synthesized by the polymerization of acetylene‐terminated M‐PS [ $\overline M _{\rm n} $  = 2 000, $\overline M _{\rm w} $ / $\overline M _{\rm n} $  = 1.20, $\overline {DP} _{\rm n} $  = 18] with an Rh catalyst. M‐PS was prepared by ATRP of styrene using the acetylene‐containing initiator 2‐bromo‐2‐methylpropionic acid ( S )‐1‐methylpropargyl ester ( l ). In solutions, poly(M‐PS) exhibited an intense CD signal at 345–355 nm, indicating that it possessed a predominantly one‐handed helical conformation. Poly(M‐PS) had a stable helical conformation irrespective of solvents and temperature.