A series of AB2-type miktoarm star azobenzene polymers carrying one polystyrene(PS)arm and two poly[6-[4-(4’-methoxyphenylazo)phenoxy]hexyl methacrylate}(PMMAZO)arms were prepared by combination of atom transfer radical polymerization(ATRP)and chemical modification of the termini of ATRP derived polymers．The synthesis involved thme steps．The first step involved the preparation of ω-bromopolystyrene(PS)chain by ATRP using ethyl 2-bromoisobutyrate as initiator．Next

the bromo end groups of the resulting PS chains were derivatized into ω．ω-bis(bromo)-PS chains．The last step consisted of growing two PMMAZO arms by ATRP in chlorobenzene These precursors and miktoarm star polymers were characterized by proton nuclear resonance (1H—NMR)

and gel permeation chramatograpy(GPC)．The information of PS(Br)2 and PS(PMMAZO)2 star pdymers confirmed the expected structure．The liquid crystailline(LC)behavior of these eopolymers was studied by DSC and POM．It was found that the miktoarm star copolymem had LC properties similar to PMMAZO those of homopdymer

and their thermal stability of the mesophases was improved

while the phase transition enthalpies were reduced.