Nanostructured Macromolecules and Carbon-based Materials

本研究旨在研究共轭聚合物与单壁碳纳米管之间的选择性相互作用。目前，由于难以提纯、分离和分散特定类型的纳米管，单壁碳纳米管在许多应用中的巨大技术前景无法在商业规模上实现，从柔性触摸屏到用于爆炸物或毒素痕迹的传感器。最近的研究表明，共轭聚合物可以结合到单壁碳纳米管的表面，生成的络合物具有良好的溶解性和较高的纯度。这种提纯纳米管的方法很有前途，因为它可以轻松且经济有效地扩大到工业水平。我们最近发现，共轭聚合物的电子性质可以决定它们与半导体(S)单壁碳纳米管相互作用的偏好，而不是金属(M)单壁碳纳米管。富电子聚合物偏好S-单壁碳纳米管，而贫电子聚合物偏好m-单壁碳纳米管。现在的挑战是通过制造尽可能少电子的共轭聚合物来提高分散的m-SWNTs的纯度，这是本提案的目标之一。这将通过用吸电子基团装饰聚合物主链来实现。我们还将研究在发生选择性相互作用和分离/纯化纳米管后，将共轭聚合物从单壁碳纳米管表面移除的方法。这将通过制备结合到单壁碳纳米管表面的可降解聚合物来实现，然后可以解聚回其原始单体组分(可以回收)。此外，我们还将探讨与单壁碳纳米管最佳相互作用所需的聚合物结构类型的基本问题，特别关注共轭聚合物是否确实是必需的。我们将制备包含由非共轭链段分隔的共轭单元的新结构，并将优化这些聚合物与单壁碳纳米管的相互作用。最后，我们将通过与共轭聚合物的超分子相互作用将分子识别元件连接到单壁碳纳米管表面，以便将感官特性赋予最终的组装件。将准备传感器设备，并测量它们对国防和执法应用中感兴趣的特定分析物的反应。

This proposal aims to investigate the selective interactions between conjugated polymers and single-walled carbon nanotubes (SWNTs). Currently, the enormous technological promise of SWNTs in numerous applications, ranging from flexible touch screens to sensors for traces of explosives or toxins, cannot be realized on commercial scale because of difficulty in purifying, isolating, and dispersing specific nanotube types. Recently, it has been demonstrated that conjugated polymers can bind to the surface of SWNTs, producing complexes that exhibit solubility and enhanced purity. This approach to nanotube purification is promising as it can be easily and cost-effectively scaled up to industrial levels. We have recently shown that the electronic properties of conjugated polymers can dictate their preference for interacting with semiconducting (s) versus metallic (m) SWNTs. While electron-rich polymers prefer s-SWNTs, electron-poor polymers show a preference for m-SWNTs. Now the challenge is to increase the purity of m-SWNTs being dispersed by making conjugated polymers that are as electron-poor as possible, which is one of the goals of this proposal. This will be accomplished by decorating the polymer backbone with electron-withdrawing groups. We will also investigate methods by which conjugated polymers can be removed from the SWNT surface after selective interactions and separation/purification of nanotubes have taken place. This will be done by preparing degradable polymers that bind to the SWNT surface, and then can be depolymerized back to their original monomer components (which can be recycled). In addition, we will explore fundamental questions about the type of polymer structure that is needed for optimal interactions with SWNTs, with particular focus on whether conjugated polymers are actually required. We will prepare new structures that contain conjugated units separated by non-conjugated segments, and will optimize the interactions of these polymers with SWNTs. Finally, we will attach molecular recognition elements to the SWNT surface through supramolecular interactions with conjugated polymers in order to impart sensory properties to the resulting assemblies. Sensor devices will be prepared, and their response to specific analytes of interest in defence and law enforcement applications will be measured.