Precise molecular ordering in discotic monolayers through supramolecular nanoarchitectonics

Abstract

Achieving a high degree of structural ordering in monolayers of disc-shaped molecules, typically comprising large aromatic cores and flexible alkyl chains, is exceptionally challenging yet essential for developing functional materials in organic electronics and optoelectronics. Here, we present a strategy, solely based on supramolecular nanoarchitectonics, wherein a careful molecular design combined with tailored self-assembly pathways enables precise control over molecular ordering. Using ambipolar amphiphilic heterocoronene derivatives, we demonstrate the ability to direct either face-on or edge-on alignment at interfaces. Incorporation of oxadiazole linkers between the heterocoronene core and peripheral alkyl chains yields mechanically robust, hydrophilic, and atomically smooth monolayers with face-on orientation, in sharp contrast to the hydrophobic, edge-on alignment observed for the parent heterocoronene lacking these linkers. The markedly enhanced elastic modulus and surface potential of the oxadiazole-functionalized monolayers at the air–water interface arise from in-plane dipolar reorganization driven by mesoscopic restructuring, as supported by joint analysis of surface-pressure and surface-potential isotherms and corroborated by atomic force microscopy measurements. These findings establish a molecular design principle for engineering cooperative dipolar alignment in two-dimensional organic architectures, offering guidelines for nanoarchitectonic control in monomolecular films and providing pathways toward emerging technologies including organic ferroelectrics, dipolar electronics, and quantum-responsive interfaces.