pi r-stacking in thiophene oligomers as the driving force for electroactive materials and devices
The pi-stacking between aromatic oligomers has been extensively studied for many years, although the notion of exploiting this phenomenon as the driving force for molecular actuation has only recently emerged. In this work we examine with MP2 and Car-Parrinello ab initio calculations the actuation properties of a novel class of thiophene-based materials introduced by Swager et al. (Adv. Mater. 2002, 14, 368; J. Am. Chem. Soc. 2003, 125, 1142). The chemical ingredients of the assembly, calixarenes and oligothiophenes, are screened separately to characterize the actuation mechanisms and design optimal architectures. In particular, ab initio methods are used to study pi-stacking in mixed-valence oligothiophene dimers, revealing strong interactions that can be turned on and off as a function of the electrochemical potential. We show how these interactions could be harnessed to achieve molecular actuation and investigate the response of an active unit in real time with first-principles molecular dynamics simulations.
Keywords: polycyclic aromatic-hydrocarbons ; conjugated polymer actuators ; der-waals complexes ; conducting polymer ; electromechanical actuators ; ultrasoft pseudopotentials ; molecular actuators ; cation radicals ; ab-initio ; dimers
Record created on 2012-06-29, modified on 2016-08-09