Vesicle-to-spherical micelle-to-tubular nanostructure transition of monomethoxy-poly(ethylene glycol)-poly(trimethylene carbonate) diblock copolymer.
Vesicle-to-spherical micelle-to-tubular nanostructure transition of monomethoxy-poly(ethylene glycol)-poly(trimethylene carbonate) diblock copolymer.
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DOI：
10.1021/jp711291x
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发表时间：
2008-06
期刊：
影响因子：
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通讯作者：
So Young Kim;K. Lee;S. Han;B. Jeong
中科院分区：
文献类型：
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作者：
So Young Kim;K. Lee;S. Han;B. Jeong
最近，我们报道了一种温度敏感的可生物降解的单甲氧基聚乙二醇b-聚三亚甲基碳酸酯嵌段共聚物(mpeg-ptmc；大分子2007，40,5519-5525)。在本文中，我们报告了聚合物在水中随聚合物浓度和温度的变化而发生的详细形态转变，并用低温透射电子显微镜(Cryo-TEM)进行了研究。当聚合物浓度较低时(0.05wt%)，mpeg-ptmc两嵌段共聚物在水中形成囊泡。另一方面，随着聚合物浓度的增加，发生了从囊泡到胶束的转变。聚合物在2.0wt%以上主要形成胶束。在2.0wt%的聚合物溶液中，当温度从10℃升高到40℃时，mpeg-PTMC经历了从球形胶束到管状纳米结构的转变，并且随着聚合物聚集体表观尺寸的增大，聚合物水溶液的浊度也随之增加。在这里，我们报道了囊泡、球形胶束和管状纳米结构的形态是由热敏聚合物mpeg-ptmc可逆控制的，并且可以用低温透射电子显微镜仔细地跟踪形态的变化。这不仅为控制两亲性聚合物的形态提供了重要的方法，而且有助于我们对聚合物的温度敏感转变机理的理解。
Recently, we reported a temperature-sensitive biodegradable diblock copolymer of monomethoxy-poly(ethylene glycol)-b-poly(trimethylene carbonate) (mPEG-PTMC; Macromolecules 2007, 40, 5519-5525). In this paper, we report the detailed morphological transition of the polymer in water as a function of polymer concentration and temperature, using cryo-transmission electron microscopy (cryo-TEM). At a low polymer concentration (0.05 wt %), the mPEG-PTMC diblock copolymers formed vesicles in water. On the other hand, vesicle-to-micelle transition was observed as the polymer concentration increased. The polymer predominantly formed micelles above 2.0 wt %. In the 2.0 wt % polymer solution, the mPEG-PTMC underwent spherical micelle-to-tubular nanostructure transition as the temperature increased from 10 to 40 degrees C, and the transition accompanied an increase in turbidity of the polymer aqueous solution due to the increase in the apparent size of the polymer aggregates. Here, we report that the morphology of vesicles, spherical micelles, and tubular nanostructures is reversibly controlled by a thermosensitive polymer of mPEG-PTMC and the variation of the morphology can be carefully traced by using cryo-TEM. This paper will not only provide an important method for morphological control of an amphiphilic polymer but also improve our understanding of a temperature-sensitive transition mechanism of the polymer.