Supramolecular Self-Assembly of Ionic Discotic Liquid Crystalline Dimer with DNA at Interfaces

摘要

Nanoarchitectonics through ionic self-assembly at interfaces is an attractive approach to obtain advanced functional materials. Here, a novel discotic dimer-DNA complex hybrid system has been investigated at air-water and air-solid interfaces. The ionic discotic liquid crystalline dimer consisted of two triphenylene cores linked via alkyl spacer with a imidazolium moiety. At air-water interface, the dimer formed a stable monolayer with a reversible collapse. The surface manometry results suggested that the condensed phase of the monolayer consisted of molecules arranged in an edge-on conformation. To understand the folding behavior of the molecules, DFT calculations were carried out which showed that the quantum chemically optimized folded-form of the molecule was electronically more stable than its unfolded-form. Upon adding DNA to the subphase, a complex monolayer was formed with enhanced stability as was indicated by increased collapse pressure and decreased limiting area. Importantly, this complexation enabled an efficient and stable multilayer formation on silicon substrates with layers as many as 40. Since both DNA and discotic dimer molecules share common properties of one-dimensional charge transport with compatible structures, this complex film could serve as a model system for organic electronics.