以色胺(Tryp)、聚(丙二醇)双(2-氨基丙醚)(D-400)、多聚甲醛为原料，简单共聚制备一系列吲哚基聚六氢三嗪(IN-PHT)聚合物薄膜材料，该聚合物薄膜经MgCl2水溶液浸泡后烘干，得到Mg2+-吲哚动态交联的聚六氢三嗪(Mg-IN-PHT)薄膜材料。元素分布图证实Mg2+在聚合物Mg-IN-PHT中存在且分布均匀。利用理论计算模拟、紫外可见吸收光谱法、荧光光谱法等手段证明了Mg-IN-PHT薄膜中Mg2+和吲哚基团间阳离子-π相互作用的形成。通过循环拉伸测试表征了Mg-IN-PHT薄膜的力学性能，测试结果表明，Mg-IN-PHT薄膜具有较强的抗拉强度(16.1 MPa)和韧性(206.2%)，明显高于IN-PHT薄膜(11.0 MPa, 117.0%)。一方面，阳离子-π动态交联增大了聚合物网络中的交联密度，从而增强了薄膜的强度；另一方面，柔性聚合物网络受到外部刺激时易发生分子链的滑移，“点-面”阳离子-π相互作用可以更容易地形成和解除，能量耗散效果较好，从而提高了材料的韧性。同时研究了薄膜材料的热稳定性变化，结果表明Mg-IN-PHT薄膜热分解温度(280°C)和玻璃化转变温度Tg(-10°C)均高于IN-PHT薄膜热分解温度(234°C)和Tg(-16°C)。另外，动态的“点-面”阳离子-π相互作用赋予了Mg-IN-PHT膜优异的可修复和可回收性能。
A series of indole-based poly(hexahydrozine) (IN-PHT) flexible film materials were prepared by simple copolymerization of tryptamine (Tryp), poly(propylene glycol) bis(2-aminopropyl ether) (D-400), and paraformaldehyde, and the films were soaked in MgCl2 solution to prepare Mg-poly(hexahydrozine) (Mg-IN-PHT) film crosslinked by Mg2+-indole interaction. The uniform distribution of Mg2+ in Mg-IN-PHT was confirmed by EDS. The formation of cation-π interaction between Mg2+ and indole were demonstrated by UV, RF and theoretical calculation. The mechanical properties of Mg-IN-PHT films were characterized by cyclic tensile tests. The results indicated that Mg-IN-PHT films had stronger tensile strength (16.1 MPa) and toughness (206.2%), which were significantly higher than IN-PHT films (11.0 MPa, 117.0%). On the one hand, cation-π cross-linking increased the cross-linking density, thus enhancing the strength of film; On the other hand, the molecular chains of flexible polymer network slips easily when it was externally stimulated. So that the "point-surface" cation-π interactions could be formed and released more easily, and the energy dissipation effect was better, thus the toughness of film was improved. In addition, the thermal stability of Mg-IN-PHT was also investigated. The results indicated that the thermal decomposition temperature (280°C) and Tg (-10°C) of Mg-IN-PHT films were higher than that of IN-PHT films (234°C) and (-16°C). Finally, the dynamic “point-surface” cation-π interaction endowed Mg-IN-PHT films with excellent self-healing and recycling ablities.