A novel amphiphilic poly(butylene succinate) PBS copolymer bearing sulfonate pendent groups was synthesized via a two-step synthetic strategy.First

unsaturated copolyester poly(butylene succinate-co-butylene fumarate)

P(BS-co-BF) was prepared via the solution polymerization of the succinic acid

fumaric acid and 1

4-butanediol in the presence of titanium tetraisopropoxide as the catalyst.Second

sulfonation of P(BS-co-BF) was carried out by the reaction with slight excess of NaHSO3 in 2-methoxyethanol/water mixture (120℃ for 12~26 h)

resulting in 100% sulfonation

and PBS copolymers bearing sulfonate groups

P(BS-co-SBS)s

were obtained.To establish structure-function relationships

three copolymers

P(BS-co-SBS)s with different SBS molar contents were synthesized

and the SBS molar content in the P(BS-co-SBF)s was 18%

27% and 40%

respectively.The chemical structures of copolymers were characterized by 1H-NMR

FTIR and gel permeation chromatography (GPC).Moreover

self-assemblies behavior of these amphiphilic copolymers P(BS-co-SBS)s in water was investigated by means of UV spectrometer

and the sizes and morphologies of them were examined by dynamic light scattering (DLS) and transmission electron microscopy (TEM)

respectively.The results showed that the copolymers P(BS-co-SBS)s can self-assembly into stable

core-shell spherical

small-sized (103~165 nm

PDI:0.187~0.264) nanomicelles with negative surface charges (-35~-51 mV).In vitro drug release showed that copolymers P(BS-co-SBS)s have certain pH-responsive function.