THE AMPHIPHILIC MULTIARM COPOLYMERS BASED ON HYPERBRANCHED POLYESTER AND LYSINE: SYNTHESIS AND SELF-ASSEMBLY |
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Authors: | Jing Wang Yuan Yao Bing Ji Wei Huang Yong-feng Zhou De-yue Yan |
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Affiliation: | 1. School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites,Shanghai Jiao Tong University, Shanghai 200240, China 2. Huzhou Teachers College, Huzhou 313000, China |
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Abstract: | The amphiphilic multiarm copolymers were synthesized through the modification of commercially available hyperbranched polyesters (Boltorn H40) with N-ε-carbobenzoxy-L-Lysine N-carboxyanhydride (ZLys-NCA). After being condensed with N-Boc-phenylalanine (Boc-Nphe) and deprotected the Boc-groups in trifluoroacetic acid (TFA), the original terminal hydroxyl groups were transformed into the amino groups and then initiated the ring-opening polymerization of ZLys-NCA. The hydrophilic poly(L-lysine) was grafted to the surface of Boltorn H40 successfully after the protecting benzyl groups were removed by the HBr solution in glacial acetic acid (33 wt%). The resulting multiarm copolymers were characterized by the 1H-NMR, GPC and FTIR. The arm length calculated by NMR and GPC analysis was about 3 and 13 lysine-units for H40-Phe-PLys1 and H40-Phe-PLys2 respectively. Due to the amphiphilic molecular structure, they displayed ability to self-assemble into spherical micelles in aqueous solution with the average diameter in the range from 70 nm to 250 nm. The CMC of H40-Phe-PLys1 and H40-Phe-PLys2 was 0.013 mg/mL and 0.028 mg/mL, respectively,indicating that H40-Phe-PLysl with shorter ann length is easier to self-assemble than H40-Phe-PLys2 with longer arm length. |
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Keywords: | N-ε-carbobenzoxy-L-Lysine N-carboxyanhydride Amphiphilic multiarm copolymer Hyperbranched polyester Modification Self-assembly |
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