分析型超速离心用于不同拓扑结构的聚合物的表征

Macromolecules with different topologies have received much attention due to their unique properties that are fundamentally different from linear polymers. Accurate characterization of these macromolecules can help us to understand the relationship between structure and properties. Size exclusion chromatography is most widely used method to characterize polymers, however this method separates regarding hydrodynamic volume of polymer samples, that is, polymer chains with different molar masses can co-elute due to differences in their topological structures, so that absolute molar mass and distribution characterization of some macromolecules with different topologies such as hyperbranched polymers is still an unresolved issue. We propose to use analytical ultracentrifuge and size exclusion chromatography to characterize the absolute molar mass and distribution of macromolecules with different topologies and the relationship between absolute molar mass and thermodynamic parameters such as size and sedimentation coefficient. The outcome of the research is that an experimental method will be developed to characterize macromolecules with different topologies and we will have a better understanding of the relationship between molar mass and the thermodynamic parameters which will help us to understand the relationship between structure and properties.

不同拓扑结构的高分子因具有与线型高分子不同的独特性质而受到人们的广泛关注。准确表征这类高分子可使我们深入了解其结构与性能之间的关系。由于表征方法的局限，如按分子流体力学体积分离的尺寸排除色谱方法中，分离出来的某级分可能含有相同流体力学体积，但具有不同分子量的组分，导致某些拓扑结构高分子如超支化高分子的绝对分子量及分布还不能准确测量。针对以上关键问题，我们在本项目中提出，利用分析型超速离心结合尺寸排除色谱研究不同拓扑结构高分子的绝对分子量及分布，分子量与尺寸及沉降系数等热力学参数的关系。通过该项目的完成，我们不仅可以发展一种表征不同拓扑结构高分子的实验方法，而且可以测得并深入认识分子量对各热力学参数的影响，为深入了解这类高分子的结构与性能之间的关系提供依据。

不同拓扑结构的高分子因具有与线型高分子不同的独特性质而受到人们的广泛关注。由于表征方法的局限，如按分子流体力学体积分离的尺寸排除色谱方法中，分离出来的某级分可能含有相同流体力学体积，但具有不同分子量的组分，导致不能准确测量某些具有拓扑结构高分子的绝对分子量。通过本基金的资助，我们发展了将尺寸排除色谱和分析型超速离心联用的方法，并用该方法用于分离和表征超支化和线型聚苯乙烯的混合溶液，获得了不同拓扑结构聚合物的绝对分子量。同时，我们发展了一种合成环型聚苯乙烯磺酸钠的方法，通过合成的一系列线型和环型的聚苯乙烯磺酸钠样品，利用分析型超速离心方法，获得了环型聚苯乙烯磺酸钠的沉降系数与重复单元数目之间的标度关系。另外，我们还利用分析型超速离心等方法研究了DNA与配体之间的相互作用以及大豆蛋白的结构等。依托本项目的资助，共发表包括Macromolecules, ACS Macro Letters和Journal of Physical Chemistry B在内的SCI论文12篇，指导2名博士和5名硕士。