Department of Chemistry, Université de Montréal, C.P. 6128, Succursale Centre-ville, Montréal, QC H3C 3J7, Canada.
Langmuir. 2011 Sep 6;27(17):11174-9. doi: 10.1021/la2021929. Epub 2011 Aug 12.
Poly(allyl glycidyl ether) (PAGE) and poly(ethylene glycol) (PEG) blocks were sequentially grown via anionic polymerization to form four block copolymer arms on a cholic acid (CA) core, yielding star block copolymers (CA(AGE(8)-b-EG(n))(4)) with low polydispersities (ca. 1.05). The introduction of PAGE segments into CA(PEG)(4) significantly reduced their crystallinity. The polymers can aggregate in water at room temperature above their critical aggregation concentration. The copolymers are thermoresponsive; their behavior in aqueous solutions was studied by the use of UV-visible spectroscopy, dynamic light scattering, and transmission electron microscopy. Their cloud points vary from 13 to 55 °C with increasing length of the PEG segments. Double thermoresponsive behavior was observed with short PEG segments because of a two-step transition process: small micelles are formed upon heating and then further aggregate into micellar clusters through the association of PEG chains.
聚（烯丙基缩水甘油醚）（PAGE）和聚乙二醇（PEG）链段通过阴离子聚合顺序生长，在胆酸（CA）核心上形成四个嵌段共聚物臂，得到星型嵌段共聚物（CA（AGE（8）-b-EG（n））（4）），具有较低的多分散性（约 1.05）。PAGE 段的引入显著降低了 CA（PEG）（4）的结晶度。聚合物在室温下高于其临界聚集浓度时在水中聚集。共聚物具有温敏性；通过使用紫外-可见光谱、动态光散射和透射电子显微镜研究了它们在水溶液中的行为。随着 PEG 段长度的增加，其浊点从 13°C 变化到 55°C。由于两步转变过程，短 PEG 段表现出双重温敏性：加热时形成小胶束，然后通过 PEG 链的缔合进一步聚集形成胶束簇。
