Nanosystem Research Institute (NRI), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 2, Tsukuba, Ibaraki, Japan.
Phys Chem Chem Phys. 2013 Jun 21;15(23):9265-70. doi: 10.1039/c3cp44150d. Epub 2013 May 9.
We theoretically investigate the energetically favorable orientation of poly(3-hexylthiophene) (P3HT) on self-assembled monolayers (SAMs) using molecular dynamics simulations. The effects of different kinds of SAMs are studied by examining a CH3-terminated SAM with a hydrophobic surface and an NH2-terminated SAM with a hydrophilic surface. We also investigate dynamic behavior of the systems with limited numbers of P3HT molecules on the SAM surfaces. The important factors in controlling the molecular orientation are elucidated from these results. We demonstrate that the edge-on orientation is more energetically favorable than the face-on orientation on both SAMs. On the other hand, the face-on orientation gains more intermolecular interaction energy between the P3HT molecules and the SAMs. This energy gain is larger in the NH2-terminated SAM than the CH3-terminated SAM. A limited number of P3HT molecules prefer to take the face-on orientation rather than the edge-on orientation. Our theoretical results suggest that the molecular orientation of P3HT is controllable by tuning the conditions of the film formation process and the intermolecular interactions between the P3HT molecules and SAMs.
我们使用分子动力学模拟理论上研究了聚(3-己基噻吩)（P3HT）在自组装单层（SAM）上的有利取向。通过研究具有疏水性表面的 CH3 封端 SAM 和具有亲水性表面的 NH2 封端 SAM 来研究不同类型 SAM 的影响。我们还研究了在 SAM 表面上具有有限数量的 P3HT 分子的系统的动态行为。从这些结果中阐明了控制分子取向的重要因素。我们证明，在两种 SAM 上，P3HT 的边缘取向比面内取向更有利。另一方面，面内取向在 P3HT 分子和 SAM 之间获得更多的分子间相互作用能。在 NH2 封端 SAM 中，这种能量增益大于 CH3 封端 SAM。有限数量的 P3HT 分子更倾向于取面内取向而不是边缘取向。我们的理论结果表明，通过调整薄膜形成过程的条件和 P3HT 分子与 SAM 之间的分子间相互作用，可以控制 P3HT 的分子取向。
