γ-环糊精与乙烯基嵌段共聚物非适配包结产物制备研究

In this study, a series of amphiphilic vinyl block copolymers featured by PMMA or PMAA as a central block and continuously changing lengths of the side chain of outer blocks were first synthesized using the Cu(0)/Me6TREN mediated atom transfer radical polymerization (ATRP), and then were allowed to self-assemble with γ-CDs in aqueous solution to assess the threshold value of side chain lengths of the monomers enabling to create over-fit inclusion complexes (ICs) or polypseudorotaxanes (PPRs). Thereafter γ-CDs were further used to accommodate the resulting vinyl block copolymers to prepare PPRs containing both the over-fit and matched inclusion complexation structures. Moreover, in the presence of Cu(0)/Me6TREN, these PPRs were employed as supramolecular initiators to initiate the ATRP of hydrophobic vinyl monomers having the side chain lengths longer than the threshold value for generating over-fit ICs so that they were transformed into the same configurational polyrotaxane (PR)-based block copolymers. To shed light on the self- assembly mechanism of the unmatched inclusion complexation process and to clarify the retarding effect of varying side chain lengths of vinyl block copolymers on the movement (sliding and rotating) of threaded γ-CDs along different polymeric blocks, thermodynamic parameters of the self-assembly systems were determined, changes of corresponding proton resonance peaks in 1H NMR and 2D NOESY H-H NMR were traversed as well as the occurrences of characteristic channel-like crystal structure were observed in the XRD patterns for the matched inclusion complexation of γ-CDs with the central PMMA or PMAA block of the amphiphilic vinyl block copolymers. Finally, the reversible controlling of movement of the threaded γ-CDs along the different polymeric blocks was intended by taking advantage of changing solvents and annealing temperature and time, pH, alternating stress, dielectric relaxation, etc., wherein a kind of the polyrotaxane-based smart materials showing the stimuli- and dynamic responsibility are expected.

以Cu(0)/三(2-二甲氨乙基)氨(Me6TREN)为催化剂，利用双位点引发剂引发侧链长度可连续变化的亲、疏水性(甲基)丙烯酸酯单体进行ATRP，制备PMMA或PMAA为中间嵌段的两亲性嵌段共聚物。通过将其与γ-CD自组装包结确定能够形成过紧非适配包结聚准轮烷的单体侧链长度阈值。随后，以该聚准轮烷为引发剂，引发侧链长度超过能发生过紧非适配包结阈值的疏水性(甲基)丙烯酸酯单体的ATRP，将其转化为聚轮烷嵌段共聚物。通过测定包结体系的热力学参数，分析包结过程中核磁氢谱与二维相关氢-氢核磁谱峰的变化规律，观察在XRD中是否出现γ-CD与PMMA或PMAA适配包结生成特征管道结晶衍射峰等，阐述γ-CD与两亲性嵌段共聚物非适配包结机理，确定侧基结构变化对链上γ-CD运动产生的阻滞作用。最终通过改变溶剂、热处理温度与时间、pH等外界刺激条件，实现对链上γ-CD在不同嵌段间运动与驻留状态的可逆调控。

利用Cu0-RDRP成功实现了NIPAM，HEMA和BMA单体的活性可控聚合，制备出双端基官能化PNIPAM，PHEMA和PBMA嵌段共聚物。研究了它们与β/γ-CD发生非适配包结形成聚准轮烷的可行性。进一步采用CuAAC反应对所获得的聚准轮烷进行了封端反应操作，使之转化为相应的聚轮烷嵌段共聚物。从γ-CD与PEO-2N3适配包结与封端反应中，首次制备出可分离的双链包结型γ-CD- PEO聚轮烷。这类聚轮烷是我们长期致力追求的研究目标之一。. 与此同时，为拓展CD主-客体超分子聚合物在生物材料领域的应用范围，本研究工作通过异氰酸酯反应将β-CD引入到PCL两端，得到β-CD封端的PCL，并将其与多官能度金刚烷衍生物发生无溶剂主-客体包结，获得一类具有形状记忆功能的超分子生物材料。. 还将二茂铁组分通过缩合反应引入PEG主链上形成大分子客体，再利用β-CD与二茂铁选择性包结和相应的封端反应得到具有可控穿嵌量的聚轮烷。利用该聚轮烷作为交联剂分别交联PEG和PC，得到具有超分子滑环结构的交联聚氨酯弹性体。它们所表现出的优异力学性能预示着滑环结构作为能量耗散基元可用于增韧材料的分子设计与合成中。