自组装基化二维共价有机框架的增强水解稳定性
Laura M Lanni1, R William Tilford, Muktha Bharathy
1Department of Chemistry and Biochemistry, University of South Carolina, Columbia, 29208, United States.
Journal of the American Chemical Society
|August 3, 2011
概括
在共价有机框架 (COF) 的孔隙中化显著提高了它们在水环境中的稳定性. 与非基化框架相比,基化COF显示出更好的结构完整性和孔隙性保留,显示出稳定性增加了50倍.
科学领域:
- 材料科学 材料科学 材料科学
- 聚合物化学 聚合物化学
- 纳米技术 纳米技术
背景情况:
- 聚合有机框架 (COF) 是具有可调节性质的晶体多孔聚合物.
- 酸 Ester-linked COFs 在水性环境中容易发生水解,这限制了它们的应用.
- 了解影响COF稳定性的因素对于开发坚固材料至关重要.
研究的目的:
- 调查孔口化对水性介质中二维酸 Ester-linked COFs 的稳定性的影响.
- 为了比较化COF与非化 (裸孔) COF的水解稳定性.
- 量化化对水解和多孔性损失的保护作用.
主要方法:
- 裸孔COFs (COF-18Å,COF-5) 和化孔COFs (COF-16Å (甲基),COF-14Å (乙基),COF-11Å (基)) 的合成和表征.
- 用BET分析对COF暴露于水性环境 (中性,酸性,基性) 和孔隙性的评估.
- 通过SEM,吸收光谱和1H NMR监测结构完整性和单体释放.
- 使用X射线衍射评估结晶性变化.
主要成果:
- 非化COFs (COF-18Å,COF-5) 在水性介质中快速化,几乎完全失去孔隙性和结晶性.
- 化COF (COF-16Å,COF-14Å,COF-11Å) 的稳定性显著提高,孔隙性仅下降约25%,结晶性下降约40%.
- 水解速率取决于pH值,在基本水性介质中是最快的.
- 与COF-18Å (非基化) 相比,COF-11Å (基化) 的稳定性增加了多达50倍.
结论:
- 孔口化是一种有效的策略,可以提高酸 Ester-linked COFs 的水解稳定性.
- 基化COF在水性环境中保持了显著的多孔性和结构完整性,与它们的非基化对应物不同.
- 这些发现允许设计更耐用的COF,用于需要暴露在水或潮湿条件下的应用.
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