Organic single-crystal surface-induced polymerization of conducting polypyrroles

Polypyrrole hexagonal microplates (PHMs) (50-100 microm long, 10-20 microm wide, and 0.8-1.2 microm thick) with a quasicrystalline structure and high electrical conductivity (up to 400 S/cm) are simply fabricated using single crystals of 4-sulfobenzoic acid monopotassium salt (KSBA) in aqueous medium. Moreover, the fabrication process described here differs strikingly from traditional methods, such as template-free, soft template, and hard template methods. Synthetic time-resolved polypyrrole (PPy) morphology dynamics reveals that the fabrication process of PHMs composed of PPy nanostructures combines a shape-copying process for forming a PPy preform that imitates the shape of a KSBA single crystal and the self-assembly process of PPys on the preform. The PHMs exhibit the improved pi-stacking and bipolaron structure. The strong pi-stacks among PPy rings of bipolaron structures lead to a high quasicrystalline structural order and the metallic conduction. Other single organic crystals that can act as dopants could also be grown using this approach, which will also enable the fabrication of complex micro/nanostructures on organic single crystals.