Influence of Coulombic Interaction on the Interfacial Self-Assembly of Discotic Liquid Crystal Amphiphile: A Combined Experimental and Computer Simulation Study

Self-assembly of amphiphilic molecules largely depend on the structure and electronic properties of the polar head groups. An important class of amphiphiles with technological applications is the discotic liquid crystal (DLC) amphiphiles. Here, we report remarkable differences in the self-assembly properties of two similar discotic amphiphiles with dissimilar polar head groups, viz :, imidazole-tethered with hexaalkoxytriphenylene (neutral-ImTp) and imidazolium-tethered with hexaalkoxytriphenylene (ionic-ImTp). Surface manometry reveals that the ionic-ImTp exhibits larger limiting area, higher collapse pressure, and smaller compressional elastic modulus at air-water interface as compared to the neutral-ImTp system. At air-solid interface, ionic-ImTp can be transferred only up to a bilayer structure with undulated morphology, whereas the neutral-ImTp exhibits smooth morphology and higher transfer efficiency. These results are explained by DFT calculations and molecular dynamics (MD) simulations which eluci...