多酸团簇基遥爪型聚合物的流变学研究：一种簇际相互作用的定量测试方法

充分认识簇际相互作用对于理解团簇的形成机制、揭示构效关系、构造高性能的团簇材料与器件极为重要。但据我们所知，尚未有研究报道定量表征簇际相互作用的方法。本申请项目拟通过多酸团簇基遥爪型聚合物的流变学研究，回答团簇领域中的一个基本科学问题：如何定量表征簇际相互作用。一、精准合成以多酸团簇为端基的，非缠结的遥爪型聚苯乙烯。其中，多酸团簇和聚合物之间是通过共价连接的。二、研究该类簇基遥爪型聚合物在溶液、熔体和固态中的自组装行为，揭示这些自组装行为与多酸团簇结构、抗衡阳离子、桥连的聚苯乙烯分子量之间的关联性，定性分析其簇际相互作用机制。三、研究该类簇基离聚物的流变学性质，并结合分子流变学理论解析得到团簇解离特征时间τs。簇际相互作用能，也就是缔合能Ea与τs、热运动特征能量kT、热运动特征时间τ0应满足如下关系：Ea = kTln(τs/τ0)。进而，建立定量测试簇际相互作用的流变学方法。

Full understanding inter-cluster interactions are fundamentally important for elucidating formation mechanism and structure-property relationship of clusters and constructing high-performance cluster based materials and devices. However, to the best of our knowledge, there has been no method for quantifying the inter-cluster interactions. This proposal will answer the fundamental scientific question of how to quantitatively characterize inter-cluster interactions, by investigating rheology of polyoxometalate (POM) based telechelic polymers. (i) We will precisely synthesize a series of POM based telechelic polymers, wherein the central polystyrene chains are nonentangled, and covalently linked with end-functionalized POM clusters. (ii) Their self-assembled behaviors in solution, melting and solid states are studied in detail. Moreover, we will build a substantial relationship of the self-assembled behaviors with POM structures, countercations, and molecular weights of the central polystyrene chains. Therefore, the corresponding inter-cluster interactions are qualitatively analyzed. (iii) The rheological properties of the POM based telechelic polymers are investigated in detail. The resulting rheological data are quantitatively fitted by the molecular theory for the ion-containing polymer rheology. Therefore, the ratio of the characteristic time of POM dissociation, τs, to an attempt time of segmental motion, τ0, can be related to the association energy of the inter-POM interaction: Ea = kTln(τs/τ0), where k is the Boltzmann constant and T is the absolute temperature. Accordingly, the ratio of the temperature dependences enables us to precisely determine Ea that is consistent with Ea determined directly from the value of τs/τ0 at given T. Therefore, a rheological protocol is constructed for quantitatively measuring inter-cluster interactions on the basis of POM based telechelic polymers.