Sonagashira coupling reaction between 4-bromobenzyl alcohol and trimethylsilylacetylene was carried out and then the trimethylsilyl group was removed to give 4-ethynylbenzyl alcohol.Living ring-opening polymerization of lactide was performed under normal pressure and temperature by using DBU as a catalyst and 4-ethynylbenzyl alcohol as an initiator.1H-NMR spectra and GPC were employed to characterize the chemical structure of the products and analyze the molecular weight and polydispersity.The results indicated that polylactide macromonmers bearing 4-ethynylbenzyloxy end group(PA-PLLA-3k

PA-PLLA-4k

PA-PDLA-3k

and PA-PDLA-4k) were successfully synthesized

and the molecular weight of the macromonmers was controlled effectively.Homopolymerization of the macromonomers was carried out by using [Rh(nbd)Cl]2/Et3N as the catalyst to give poly(phenylacetylene)s with polylactide side chains (poly(PA-PLLA)-3k

poly-(PA-PLLA)-4k

poly(PA-PDLA)-3k and poly(PA-PDLA)-4k).The poly(phenylacetylene)s were characterized by GPC

GPC-MALLS and 1H-NMR.The results indicated that poly(PA-PLLA) and poly(PA-PDLA) possess linear flexible chain with high molecular weight.CD and UV-Vis spectra of the poly-(phenylacetylene)s showed that poly(PA-PLLA) and poly(PA-PDLA) main chains assuredly possess predominantly one-handed helical conformations

and the direction of Cotton effects was affected by the chirality of macromonomers.The direction of Cotton effects of the poly(phenylacetylene)s was the same when the chirality of macromonomers was the same

Cotton effects of the poly(phenylacetylene)s were reverse when the chirality of macromonomers was reverse.The intensity of Cotton effects was various in different solvents

this meant that the regularity of helical conformation of the poly(phenylacetylene) main chain was variable in different solvents.Moreover

the stability of helical conformation of poly(phenylacetylene) decreased with the increasing temperature.