Solid-state complexation of poly(ethylene glycol) with α-cyclodextrin
Solid-state complexation of poly(ethylene glycol) with α-cyclodextrin
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DOI：
10.1021/ma048103f
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发表时间：
2005-01-25
期刊：
影响因子：
5.5
通讯作者：
Balik, CM
中科院分区：
文献类型：
--
作者：
Peet, J;Rusa, CC;Balik, CM
低分子量液态聚乙二醇 (PEG) 在室温下与 α-环糊精 (α-CD) 粉末结合时会自发形成包合物 (IC)。此过程可通过广角 X 射线衍射 (WAXD) 进行跟踪。 WAXD 数据显示，在 IC 形成后，α-CD 晶体在约 8 小时的时间内经历了从笼形晶体结构到通道晶体结构的固态晶体转变。 2theta=20度α-CD通道结构X射线峰的时间依赖性可以通过简单的一级动力学模型来描述。研究了改变温度、PEG:α-CD 摩尔比、PEG 分子量和真空干燥 CD 的影响。阻碍 PEG 包合诱导的 a-CD 从笼状晶体结构转变为通道晶体结构的障碍似乎主要是 α-CD 的堆积/相互作用的变化，而不是 PEG 链在包合过程中经历的构象熵的损失。
Low-molecular-weight liquid poly(ethylene glycol) (PEG) spontaneously forms an inclusion compound (IC) when combined with alpha-cyclodextrin (alpha-CD) powder at room temperature. This process can be followed with wide-angle X-ray diffraction (WAXD). The WAXD data shows that the alpha-CD crystals undergo a solid-state crystal-crystal transformation from the cage to the channel crystal structure upon IC formation over a period of about 8 h. The time dependence of the 2theta = 20degrees alpha-CD channel structure X-ray peak can be described by a simple first-order kinetic model. The effects of changing the temperature, PEG:alpha-CD molar ratio, PEG molecular weight, and vacuum-drying the CD have been studied. The barrier opposing the PEG inclusion-induced solid-state transformation of a-CD from the cage to the channel crystal structure appears to be dominated by changes in the packing/interactions of alpha-CDs, rather than the loss in the conformational entropy experienced by the PEG chains during the inclusion process.