Analytical Science and Technology Laboratory of Hebei Province, College of Chemistry & Environmental Science , Hebei University , Baoding , 071002 Hebei , China.
Department of Chemical Engineering , Auburn University , Auburn 36849 , United States.
ACS Appl Mater Interfaces. 2019 Jan 30;11(4):4258-4267. doi: 10.1021/acsami.8b19180. Epub 2019 Jan 17.
Three-dimensional (3D) nanostructured conducting polymer hydrogels represent a group of high-performance electrochemical energy-storage materials. Here, we demonstrate a molecular self-assembly approach toward controlled synthesis of nanostructured polypyrrole (PPy) conducting hydrogels, which was "cross-linked" by a conjugated dopant molecule trypan blue (TB) to form a 3D network with controlled morphology. The protonated TB by ion bonding aligns the free sulfonic acid groups into a certain spatial structure. The sulfonic acid group and the PPy chain are arranged by a self-sorting mechanism to form a PPy nanofiber structure by electrostatic interaction and hydrogen bonding. It is found that PPy hydrogels doped with varying dopant concentrations and changing dopant molecules exhibited controllable morphology and tunable electrochemical properties. In addition, the conjugated TB dopants promoted interchain charge transport, resulting in higher electrical conductivity (3.3 S/cm) and pseudocapacitance for the TB-doped PPy, compared with PPy synthesized without TB. When used as supercapacitor electrodes, the TB-doped PPy hydrogel reaches maximal specific capacitance of 649 F/g at the current density 1 A/g. The result shows that PPy nanostructured hydrogels can be tuned for potential applications in next-generation energy-storage materials.
三维（3D）纳米结构导电聚合物水凝胶是一组高性能电化学储能材料。在这里，我们展示了一种分子自组装方法，用于可控合成纳米结构聚吡咯（PPy）导电水凝胶，该水凝胶由共轭掺杂剂分子锥虫蓝（TB）“交联”形成具有可控形态的 3D 网络。通过离子键合质子化的 TB 将游离磺酸基团排列成特定的空间结构。磺酸基团和 PPy 链通过自排序机制排列，通过静电相互作用和氢键形成 PPy 纳米纤维结构。研究发现，掺杂不同掺杂浓度和掺杂分子的 PPy 水凝胶表现出可控的形态和可调谐的电化学性能。此外，共轭 TB 掺杂剂促进了链间电荷输运，使得 TB 掺杂的 PPy 具有更高的电导率（3.3 S/cm）和赝电容，与没有 TB 合成的 PPy 相比。当用作超级电容器电极时，TB 掺杂的 PPy 水凝胶在电流密度为 1 A/g 时达到最大比电容 649 F/g。结果表明，PPy 纳米结构水凝胶可以进行调节，以潜在应用于下一代储能材料。
