Max Planck Institute for Polymer Research , Ackermannweg 10, D-55128 Mainz, Germany.
Department of Physics, University of Ioannina , 45110 Ioannina, Greece.
ACS Appl Mater Interfaces. 2017 Jun 21;9(24):20527-20535. doi: 10.1021/acsami.7b03060. Epub 2017 Jun 9.
Benzothiadiazoles are important electron acceptors and are frequently employed as electron-deficient components of donor-acceptor polymers. We report the effect of nitrile functionalities on the reactivity, steric hindrance, optoelectronic properties, and dielectric permittivity in dicyanobenzothioadiazole (DCNBT). Dielectric spectroscopy in the bulk and in solution assisted by DFT-calculations revealed that these molecules can be engineered to engender maximum values of the dipole moment and of dielectric permittivity due to the strong electron-withdrawing effect of the nitrile groups. The self-assembly in the bulk was investigated by X-ray scattering performed on single crystals, fibers (2D-WAXS), and thin films (GiWAXS). Combining these results, we found a switching of dielectric permittivity of the 4,7-alkylthienyl-substituted dicyanobenzothiadiazole at the transition from the liquid crystalline to the isotropic phase with values capable of competing with the best known rodlike liquid crystals.
苯并噻二唑是重要的电子受体，常被用作给体-受体聚合物的缺电子组分。我们报告了腈官能团对二氰基苯并噻二唑（DCNBT）反应性、空间位阻、光电性能和介电常数的影响。通过密度泛函理论（DFT）计算辅助的体相和溶液介电谱揭示，由于腈基团的强吸电子效应，这些分子可以被设计成产生最大的偶极矩和介电常数。通过对单晶、纤维（2D-WAXS）和薄膜（GiWAXS）进行 X 射线散射，研究了体相中的自组装。综合这些结果，我们发现 4,7-烷基噻吩取代的二氰基苯并噻二唑的介电常数在从液晶相到各向同性相的转变中发生了切换，其介电常数值可与已知的最好的棒状液晶相媲美。
