摘要
以C60和聚氧乙烯(PEO)复合物为研究对象,系统地研究了交叉极化时间对分子间交叉极化实验的影响.结果表明,在使用分子间交叉极化方法研究复合体系相结构和界面结构时,必须考虑交叉极化时间的影响才能获得更可靠的结论.同时,系统地改变交叉极化时间也能为分子间交叉极化实验的设计引入一个新的维度,从而可能得出一些在单个交叉极化时间下难以获得的结论.例如,本实验发现C60的分布并不完全局限于PEO的非晶区,至少部分C60和PEO的晶区在空间上比较接近.
A composite of poly （ethylene oxide） （PEO） and fullerene （C60） was prepared by lyophilization, and studied by high-resolution solid-state NMR spectroscopy. The ^1H spin-spin relaxation time （T2） of the composite was measured by ^1H-^13C cross-polarization experiments with different contact times. It was found that the choice of contact time influence the results of intermolecular cross-polarization experiments, implying that extra care should be taken to select appropriate contact time when applying the intermolecular cross-polarization method to study the phase structures of composites. On the other hand, variation of contact time may provide a new dimension for experimental design and be used to gain information that is not obtainable in conventional experiments with fixed contact time. For example, the results of our experiments showed that in the PEO/C60 composite not all the fullerene molecules are confined in the noncrystalline region of PEO, at least a portion of the C60 molecules are located close to the crystalline region.
出处
《波谱学杂志》
CAS
CSCD
北大核心
2005年第3期245-251,共7页
Chinese Journal of Magnetic Resonance
基金
上海市科委重大项目(04DZ14002)资助项目.
