Multiscale fibers via supramolecular self-assembly of a fully rigid, discotic aromatic aramid molecule

We synthesized a fully rigid, water soluble discotic-shaped aromatic aramid molecule, which can spontaneously self-assemble into multiscale fibers (from nano- to micro-scale in both length and diameter), depending on the molecular states (e.g., solution, liquid crystals and solid state). In diluted solution (below 0.086 g/mL), the discotic molecule tend to self-assemble into nanofibers. As the concentration increased (0.086–0.28 g/mL), it exhibits supramolecular liquid crystalline phase with microfiber texture. While, solid power under circumstance with 83% relative humidity favors the formation of rod-like shaped polymorphic crystals in macroscopic size. The unique ‘self-fiber-forming’ property of discotic molecules in different states makes them become an easy processing aramid fiber material, and also allow us to easily prepare microfilm with parallel-aligned nanofibers, which could be a promising candidate for ion conductivity material such as polymer proton exchange membrane (PEM) for fuel cell.