alpha Cyclodextrin/polyethylene glycolpolyrotaxane: A study of the threading process

被引：185

作者：

Ceccato, M ^{[1
]}

LoNostro, P ^{[1
]}

Baglioni, P ^{[1
]}

机构：

[1] UNIV FLORENCE,DEPT CHEM,I-50121 FLORENCE,ITALY

来源：

LANGMUIR | 1997年 / 13卷 / 09期

关键词：

D O I：

10.1021/la9609231

中图分类号：

O6 [化学];

学科分类号：

0703 ;

摘要：

Aqueous solutions of alpha-cyclodextrin (alpha-CD) and polyethylene glycol (PEG) form interesting complexes, where several alpha-CD units are penetrated by the linear polymeric PEG chain and produce a so-called ''polyrotaxane''. This supramolecular structure is stabilized by strong interactions between the alpha-CD hydrophobic internal cavity and the -CH2OCH2- moieties of PEG. When cyclodextrins have occupied the whole PEG chain, the polyrotaxanes aggregate and precipitate, forming a thick solid gel. Turbidity measurements at lambda = 400 nm were used to study the threading phenomenon. The temperature of the solution and the composition of the solvent affect the formation of polyrotaxanes in a significant way. We propose a molecular model to explain the experimental findings in terms of a multistep threading process. The Gibbs free energy related to the formation of polyrotaxanes is calculated according to the transition state theory.

引用

页码：2436 / 2439

页数：4

共 18 条

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