Using the primary amino-ended polystyrene(PS-NH2) as the macroinitiator

diblock copolymers of polystyrene-b-poly(-benzyl L-glutamate)(PS-b-PBLG) polypeptide hybrids were synthesized by the ring opening polymerization of N-carbonyl anhydride(NCA) method.The molecular weight and its distribution(Mw/Mn=1.4~1.8) were characterized by GPC.Comparing with the first segment

the molar ratios of the compound could be confirmed by 1H-NMR.The thermoproperties characterized by differential scanning calorimetry(DSC) indicate two temperature step changes at 10~20 ℃ and 70~80 ℃

corresponding to the two glass transitions of PBLG and PS

respectively.The texture of PS-b-PBLG in 1

1

2

2-tetrachloroethane(TCE) under a polarizing microscope(POM) shows relatively weak birefringence comparing with that of the PBLG homopolymer

but it still maintains some cholestericliquid crystalline properties.In structure of the shear-oriented solid film

-helical segments were arranged in hexagonal packing

while another larger period parallel to the helical axis was found in small-angle X-ray scattering(SAXS) pattern

indicating a phase-separated structure of alternative lamellar.The morphologies were observed through the transmission scanning electron microscope(TEM).Unlike the zigzag-lamellar texture of films from TCE

the texture of films dried from 1

2-dichloroethane(EDC) is stripe-shaped.The different morphology is due to the solvent effects on the rigidity of -helix

which means the shorter cycle length should be attributed to the -helical folding.It is therefore concluded the self-assembled structure of PS-b-PBLG is changed by the solvents.