Polymer-Controlled Synthesis of 1-(2-Pyridylazo)-2-Naphthol Hierarchical Architectures

The self-assembly of organic 1-(2-pyridylazo)-2-naphthol (PAN) into hierarchical architectures, such as microfibers, microrods, and sheaflike structures, in solution was successfully achieved by reprecipitation method with the assistance of thermoresponsive diblock copolymer poly(N,N-dimethylacrylamide)-b-poly(N-isopropylacrylamide) (PDMA-b-PNIPAM). It was found that the morphology modification can be readily controlled by varying the polymer concentrations. The optical absorption and fluorescence emission properties of the as-prepared PAN architectures were investigated. Time-dependent spectra of the precipitating solution for sheaflike structures formation were measured to monitor the self-assembly process of PAN molecules. The results showed that the PAN microstructures exhibited intense fluorescence emission, indicating an unusual aggregation-induced emission enhancement (AIEE) phenomenon for PAN, which has great potential for future use in optoelectronic microdevices.