Gelation Originated from Growth of Wormlike “Living Polymer” of Symmetrically Dendronized Large-Ring Crown Ether in Dilute Solutions
Gelation Originated from Growth of Wormlike “Living Polymer” of Symmetrically Dendronized Large-Ring Crown Ether in Dilute Solutions
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DOI：
10.1021/ma901494z
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发表时间：
2009-09
期刊：
影响因子：
5.5
通讯作者：
Jingjing Yan;Rupei Tang;Ben Zhang;Xingqi Zhu;F. Xi;Zi‐Chen Li;E. Chen
中科院分区：
文献类型：
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作者：
Jingjing Yan;Rupei Tang;Ben Zhang;Xingqi Zhu;F. Xi;Zi‐Chen Li;E. Chen
差示扫描量热法 (DSC)、小角 X 射线散射 (SAXS) 和荧光各向异性方法跟踪了在正十二烷中被四个第一代 Percec 型树枝 (1) 对称取代的大环冠醚从均匀溶液到凝胶的分层途径。 1/n-十二烷混合物在室温下需要相当低的凝胶浓度，约为 0.1% (w/v)。主要基于原位热SAXS测量，我们发现1/n-十二烷均相溶液冷却后，1分子首先进行溶液自组装，形成以冠醚为核、烷基尾为壳的蠕虫状胶束，这是每个横截面重复单元仅包含一个1的盘状分子的“活性聚合物”。组装的驱动力主要归因于具有不同化学性质的分子的不同区域之间的微相分离过程中自由能的减少以及亲脂性-唇...
The hierarchical pathway from homogeneous solution to gel of a large-ring crown ether symmetrically substituted with four first-generation Percec-type dendrons (1) in n-dodecane has been followed by differential scanning calorimetry (DSC), small-angle X-ray scattering (SAXS), and fluorescence anisotropy methods. The 1/n-dodecane mixture requires a rather low gelation concentration of ∼0.1% (w/v) at room temperature. Mainly on the basis of in situ thermal SAXS measurements, we have found that upon cooling from the homogeneous solutions of 1/n-dodecane the 1 molecule first undergoes a solution self-assembly to form wormlike micelle with the core of crown ether and the shell of alkyl tails, which is “living polymers” containing only one disklike molecule of 1 per cross-sectional repeating unit. The driving force of the assembly can be mainly attributed to the reduction of free energy during microphase separation among the different regions of molecules with distinct chemical properties and the lipophilic−lip...