Polymer-Assisted Crystallization and Optical Properties of Uniform Microrods of Organic Dye Sudan II

Abstract

The self-assembly of uniform single-crystalline microrods of organic dye Sudan II (1-(2,4- dimethylphenyl-azo)-2-naphthol) in solution was achieved by reprecipitation with the assistance of amphiphilic block copolymer Pluronic F127. It was found that the formation of F127 micelles was favorable for the production of uniform Sudan II microrods whereas individual F127 molecules favored the formation of Sudan II fibers. The optical absorption and fluorescence emission properties of the uniform microrods were characterized, and the time-dependent spectra of the precipitating solution for microrod formation were measured to monitor the self-assembly process of Sudan II molecules. The Sudan II microrods exhibited intense fluorescence emission, indicating an unusual aggregation-induced emission (AIE) phenomenon for Sudan II. The fluorescent microscopy investigation suggested that the obtained Sudan II microrods exhibited remarkable optical waveguide behavior, which is expected to serve as single rod active optical waveguides that can be used as building blocks for miniaturized photonic devices. Furthermore, novel Sudan II microplates, which exhibited interesting 2D optical waveguide behavior, were readily obtained by reprecipitation of Sudan II from cationic surfactant cetyltrimethylammonium bromide (CTAB) solution.

Morphology directing synthesis of benzo[a]pyrene microstructures and their photo physical properties

“…These include zero dimensional (0-D) spherical or tetrahedral quantum dots [16,17], one-dimensional (1-D) nano rods and wires from small organic compound [18][19][20] and two-dimensional (2-D) nanoplates [21], nanoribbons and nanotubes [22], microcapsule [23], organic nano flower [24], sub-microtube [25], etc. Various techniques were developed to prepare organic nano/ micro particle, such as reprecipitation [26], physical vapor deposition [27], microemultion [28], ultra-sonication [29], template method [30], self-organization [31], postchemistry [32][33][34][35], etc.…”

Quadrangular Prism: A Unique Self‐Assembly from Amphiphilic Hyperbranched PMA‐b‐PAA

“…Su et al found that the elongated truncated lozenge‐shaped single crystals were formed by the self‐assembly of poly(2‐vinylpyridine)‐ block ‐poly(ε‐caprolactone) (P2VP‐ b ‐PCL) in mixed solvent. Moreover, single‐crystalline microrods of Sudan II could be prepared by self‐assembly in the solution through reprecipitation with the assistance of amphiphilic block copolymer (F127) . These examples showed that the amphiphilic block copolymers containing crystalline polymer chains were important for the preparation of well‐defined regular prism.…”

Fluorescence properties of novel 6-butyl-2,3-dicyano-7-methyl-6H-1,4-diazepine styryl dyes containing ethyleneglycol units

“…Meanwhile, aggregation-induced emission enhancement (AIEE) has been reported not only for siloles 2 and tetraarylethylenes 3 but also for dyes, such as BODIPY, 4 4-dicyanomethylene-2,6-distyryl-4H-pyrans, 5 polyenes, 6 and Sudan II. 7 Therefore, it is of significance to find new AIEE dyes. We could find that suspended monoEG derivative showed weak AIEE.…”