Construction of supramolecular self-assembled microfibers with fluorescent properties through a modified ionic self-assembly (ISA) strategy

Highly ordered supramolecular microfibers were constructed through a simple ionic self-assembly strategy from complexes of the N-tetradecyl-N-methylpyrrolidinium bromide (C(14)MPB) surface-active ionic liquid and the small methyl orange (MO) dye molecule, with the aid of patent blue VF sodium salt. By using scanning electron microscopy and polarized optical microscopy, the width of these self-assembled microfibers is observed to be about 1 to 5 μm and their length is from tens of micrometers to almost a millimeter. The (1)H NMR spectra of the microfibers indicates that the supramolecular complexes are composed of C(14)MPB and MO in equal molar ratio. The electrostatic, hydrophobic, and π-π stacking interactions are regarded as the main driving forces for the formation of microfibers. Furthermore, through characterization by using confocal fluorescence microscopy, the microfibers were observed to show strong fluorescent properties and may find potential applications in many fields.