Synthesis, Properties, and Mechanistic Insight into the Self-Assembly of a Lamellar Fibrous Superstructure from a Synthetically Simple Discotic Molecule

Abstract

The discotic molecule 4-chloro-2,6-bis(octadecylamino)-pyrimidine-5-carbaldehyde, displays gelation behavior in dodecane, heptane, chloroform, and dichloromethane. The aggregation behavior of this material was studied by dynamic light scattering, differential scanning calorimetry, scanning electron microscopy, polarized optical microscopy, small-angle X-ray diffraction, and wide-angle X-ray diffraction techniques. Combined with molecular modeling calculations, Fourier transform infrared, and 1H NMR studies, we propose a mechanism for the self-assembly of this fibrous lamellar architecture. Notably, we have shown that the fibers grow via stacking interactions along their main axis, via hydrogen bonding along their short axis, and via van der Waals interactions (lamellae) along the third axis. This type of morphology is desirable since it provides an opportunity to synthetically control and optimize mechanical, electrical, optical, and transport properties along the length of the fiber.