Martin Luther University Halle-Wittenberg, Department of Chemistry, D-06099 Halle (Saale), Germany.
Biomacromolecules. 2010 Dec 13;11(12):3660-7. doi: 10.1021/bm1011085. Epub 2010 Nov 18.
Aliphatic polyesters having pendant azide groups were prepared by enzymatic polycondensation in the presence of lipase from Candida antarctica type B (CAL-B). The grafting reaction to the N(3)-functional polyester was carried out quantitatively at room temperature using copper-catalyzed azide-alkyne cycloaddition (CuAAC, "click" reaction) with monoalkyne-functional poly(ethylene oxide) (alkyne-PEO, M(n) = 750 g/mol). Furthermore, both enzymatic polycondensation and "click" reaction were carried out successfully in sequential one-pot reaction. The graft copolymer was surface-active and self-assembled in water. The graft copolymer had a critical aggregation concentration (cac) of 3 × 10(-2) μM in water determined by surface tension measurements. Above cac, the graft copolymer formed single chains and aggregates having a hydrodynamic radius of ∼75 nm. Furthermore, the surface activity of the polymers at the air-water interface was studied by Langmuir trough measurements. The Langmuir isotherm of the graft polymer showed a pseudoplateau resulting from desorption of PEO chains into the subphase upon compression.
脂肪族聚酯带有侧链叠氮基团，是通过脂肪酶（南极假丝酵母脂肪酶 B，CAL-B）存在下的酶促缩聚反应制备的。使用铜催化的叠氮-炔环加成反应（CuAAC，“点击”反应），可以在室温下定量地进行到 N(3)-官能聚酯的接枝反应，该反应使用单炔基官能聚（氧化乙烯）（炔基-PEO，M(n) = 750 g/mol）。此外，酶促缩聚反应和“点击”反应都可以在连续一锅反应中成功进行。接枝共聚物在水中具有表面活性并自组装。通过表面张力测量，接枝共聚物在水中的临界聚集浓度（cac）为 3 × 10(-2) μM。在 cac 以上，接枝共聚物形成具有约 75nm 水动力半径的单链和聚集体。此外，通过 Langmuir 槽测量研究了聚合物在气-水界面的表面活性。接枝聚合物的 Langmuir 等温线显示出由于 PEO 链在压缩时解吸到亚相中而产生的伪平台。
