Recognition of Stereoregularity of Poly(methacrylic acid)s with 纬-Cyclodextrin
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- 作者：Takashi Miura ; Toshiyuki Kida ; Mitsuru Akashi
- 刊名：Macromolecules
- 出版年：2011
- 出版时间：May 24, 2011
- 年：2011
- 卷：44
- 期：10
- 页码：3723-3729
- 全文大小：861K
- 年卷期：v.44,no.10(May 24, 2011)
- ISSN：1520-5835
文摘
The formation behavior of inclusion complexes between 纬-cyclodextrin (纬-CD) and poly(methacrylic acid)s (PMAAs) of different stereoregularities in water was examined by analyzing the precipitate formed by mixing 纬-CD with each PMAA in water. When syndiotactic (st-) PMAA was used as a guest, a much larger amount of precipitate was formed as compared to isotactic (it-) and atactic (at-) PMAAs. X-ray diffraction, FT-IR, and 1H NMR measurements of the precipitate indicated that 纬-CD effectively formed an inclusion complex with st-PMAA. Upon increasing the syndiotacticity of PMAA, the yield and the coverage ratio of the resulting inclusion complexes increased, suggesting that 纬-CD more effectively includes PMAA of a higher syndiotacticity. This is the first example of selective inclusion complex formation between CDs and a syndiotactic polymer. By adding 纬-CD into a mixture of st- and at-PMAAs, the selective extraction of st-PMAA was successfully achieved through 纬-CD鈥?i>st-PMAA inclusion complex formation. Additionally, the formation of a 纬-CD鈥?i>st-PMAA inclusion complex in the aqueous solution was confirmed by 1H NMR, NOESY, and dynamic light scattering measurements. By changing the pH of the solution, the formation and dissociation of the 纬-CD鈥?i>st-PMAA inclusion complex were reversibly controlled. This pH-controllable inclusion complex can be useful as a novel building block for pH-responsive materials.