Ethyl cellulose-graft-poly(-caprolactone) (EC-g-PCL) graft copolymers with controllable EC content as drug delivery material were synthesized via ring-opening polymerization in ionic liquid.The maximum molar ratio of [-CL] and [EC] glucose units calculated by 1H-NMR spectrum was 7∶1.The resutls of atomic force microscope (AFM) showed that the surface of EC-g-PCL graft copolymer membrane became rougher with increasing PCL content.The PCL segments in EC-g-PCL graft copolymers could crystallize and the crystallinity gradually decreased with decreasing PCL content.The clear spherulites structure of PCL segments could not be observed in the graft copolymers with PCL content lower than 20% from polarized optical micrographs.However

the banded spherulites of PCL were formed in the graft copolymers with higher PCL contents.The weight losses of copolymer films were all greater than that of pure PCL after degradation for 30 days in PBS solution.Moreover

the weight loss increased from 2.52% to 8.31% with increasing EC content.The introduction of EC chain to PCL promotes the degradation of PCL.The drug release results show that copolymer films with diclofenac have higher values of burst release and cumulative release than PCL.The drug release kinetics for copolymer films could be described by Ritger-Pappas equation:lnQ=0.3846lnt- 1.8538.The mechanism of drug release was Fickian diffusion.However

PCL film shows non-Fickian diffusion or the combination of diffusion and erosion mechanism.