Tuning the morphology of melamine-induced tetraphenylethene self-assemblies for melamine detecting

Abstract

Abstract We herein report the self-assemblies of H4tcbpe-MA by using 1,1,2,2-tetrakis (4-(4-carboxy-phenyl) phenyl) ethane (H4tcbpe) and melamine (MA) as building blocks. It was found that H4tcbpe-MA only gave weak emission in dimethyl formamide (DMF) solution, while strong fluorescence was observed upon addition of water in the solution (fw > 60%), implying their notable aggregation induced emission (AIE) property. Interestingly, the self-assemblies of H4tcbpe-MA showed various morphologies by changing the ratio of MA, evidenced by optical microscope (OM) and scanning electron microscopy (SEM) measurements. Nanofibers, tree-like, cuboidal microstructures and microbelts were generated with the ratio of H4tcbpe-MA at 1:0, 1:1.5, 1:3.0 and 1:6.0, respectively. The powder X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) measurements indicated that the ionic interaction, hydrogen bonding (H-bonding) and π-π stacking were the main driving forces for the fabrication of H4tcbpe-MA assemblies. It is worth noting that the self-assemblies displayed different emission colors variation dependence on the MA concentration- and relative humidity (RH). The photo-oxidation behavior of H4tcbpe-MA in solution was also investigated under visible light and 254 nm UV light.