Fabrication of fluorescent star-like supramolecular materials through a novel ionic self-assembly strategy

Abstract

Uniform star-like micro-scale materials were successfully fabricated by the complexation of a double tailed surfactant, sodium bis(2-ethyl-1-hexyl) sulfosuccinate (AOT), and a dye molecule, rhodamine B (RB), through a novel ionic self-assembly (ISA) route by using the seeds of RB. By using optical microscopy (OM), scanning electron microscopy (SEM), and small-angle X-ray diffraction (SAXD) measurements, morphology of such supramolecular materials was thoroughly investigated. The data from H NMR spectra indicated an equal molar ratio of AOT and RB in these star-like materials. The fluorescent properties of these ISA aggregates were studied through laser confocal scanning microscopy (LCSM) and fluorescence spectra. The formation of such star-like micromaterials was resulted from the delicate balance of various non-covalent interactions, including the electrostatic interactions, hydrophobic interactions, hydrogen bonding interactions as well as π-π stacking interactions, among which the electrostatic interactions between the head groups were regarded as the dominant force in promoting the supramolecular structure formation. To our best knowledge, this may be the first issue to fabricate such supramolecular structures through the ISA route with the aid of seeds from one building block.