Solution Behavior of Double-Hydrophilic Block Copolymers in Dilute Aqueous Solution
Solution Behavior of Double-Hydrophilic Block Copolymers in Dilute Aqueous Solution
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DOI：
10.1021/ma300621g
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发表时间：
2012-05
期刊：
影响因子：
5.5
通讯作者：
Olivier Casse;Andriy I. Shkilnyy;J. Linders;C. Mayer;D. Häussinger;A. Völkel;A. Thünemann;R. Dimova;H. Cölfen;W. Meier;H. Schlaad;A. Taubert
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文献类型：
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作者：
Olivier Casse;Andriy I. Shkilnyy;J. Linders;C. Mayer;D. Häussinger;A. Völkel;A. Thünemann;R. Dimova;H. Cölfen;W. Meier;H. Schlaad;A. Taubert
研究了双亲水性聚环氧乙烷-聚（2-甲基-2-恶唑啉）二嵌段共聚物在水中的自组装。等温滴定量热法，小角X-射线散射，和分析超离心表明，只有单一的聚合物链存在于溶液中。相比之下，光散射和透射电子显微镜检测聚集体的半径约。100 nm。脉冲场梯度NMR光谱证实了聚集体的存在，尽管只有2%的聚合物链发生聚集。水吸收实验表明两种嵌段的亲水性差异，这被认为是意外聚集行为的起源（根据Ke等人的早期研究[Macromolecules 2009，42，5339-5344]）。因此，数据表明，即使在双亲水性嵌段共聚物中，亲水性的差异也足以驱动聚合物聚集，这是迄今为止在很大程度上被忽视或忽略的现象。
The self-assembly of double-hydrophilic poly(ethylene oxide)–poly(2-methyl-2-oxazoline) diblock copolymers in water has been studied. Isothermal titration calorimetry, small-angle X-ray scattering, and analytical ultracentrifugation suggest that only single polymer chains are present in solution. In contrast, light scattering and transmission electron microscopy detect aggregates with radii of ca. 100 nm. Pulsed field gradient NMR spectroscopy confirms the presence of aggregates, although only 2% of the polymer chains undergo aggregation. Water uptake experiments indicate differences in the hydrophilicity of the two blocks, which is believed to be the origin of the unexpected aggregation behavior (in accordance with an earlier study by Ke et al. [Macromolecules2009, 42, 5339–5344]). The data therefore suggest that even in double-hydrophilic block copolymers, differences in hydrophilicity are sufficient to drive polymer aggregation, a phenomenon that has largely been overlooked or ignored so far.