Two-phase channel structures based on α-cyclodextrin-polyethylene glycol inclusion complexes
Two-phase channel structures based on α-cyclodextrin-polyethylene glycol inclusion complexes
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DOI：
10.1021/la048970d
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发表时间：
2004-10-12
期刊：
影响因子：
3.9
通讯作者：
Hunt, MA
中科院分区：
文献类型：
--
作者：
Topchieva, IN;Tonelli, AE;Hunt, MA
α-环糊精(CD)-聚乙二醇(PEG)包合物(IC)的广角X射线散射观察首次表明，在其形成过程中产生了两个晶型柱状修饰(I和II)。这是通过对定向IC样品进行精确的方位X射线衍射扫描而实现的。形式I的特征在于，Cd以头到头/尾到尾的顺序穿在聚乙二醇链上并沿着通道排列，而形式II由也以头到尾以及也可能是头到头/尾到尾的方式排列成列的未结合的Cd形成，这可能是由于IIC形式晶体上的模板结晶的结果。结果表明，用大分子量范围的聚乙二醇制得的离子通道结构具有相似的结构特性。以聚乙二醇8000为基础的集成电路的特征是，在复合体的组成中存在未结合的聚合物。未结合的聚乙二醇量随着聚乙二醇相对分子质量的增加而增加，从而导致IC晶体结构的更大缺陷。在此基础上提出了基于α-CD和聚乙二醇组分的集成电路多块结构。
Wide-angle X-ray scattering observations of a-cyclodextrin (CD)-poly(ethylene glycol) (PEG) inclusion complexes (ICs) have shown for the first time that two crystalline columnar modifications (forms I and II) are produced in the process of their formation. This was made possible by precise azimuthal X-ray diffraction scanning of oriented IC samples. Form I is characterized by CDs threaded onto PEG chains and arranged along channels in the order head-to-head/tail-to-tail, while form II is formed by unbound CDs also arranged into columns in a head-to-tail and also possibly a head-to-head/tail-to-tail manner, probably as a result of template crystallization on the form IIC crystals. It was shown that similar structural peculiarities are inherent for channel structures based on ICs obtained with PEG with a wide range of molecular weights (MWs). The characteristic feature of ICs based on PEG, especially with MW > 8000, is the presence of unbound polymer in the composition of the complex. The amount of unbound PEG was shown to rise with increasing MW of PEG, resulting in greater imperfections in the IC crystalline structure. The polyblock structure of ICs based on alpha-CD and PEG was therefore proposed.