A novel hydrophobic fluorescent conjugated polymer, i.e. poly[2,5-bisnonyloxy-1, 4-phenylene-ethynylene-9,10-anthrylene] (PPEA) was synthesized by a Sonogashira palladium-catalyzed cross-coupling reaction of 1,4-diethynyl-2,5-bisnonyloxy-benzene and 9,10-dibromoanthracene. And their fluorescence behaviors in aqueous solution containing different surfactants were studied. The fluorescence of PPEA was dramatically quenched in aqueous solution. However, the fluorescence gradually enhanced with the increasing of the concentration of TX-100. Other surfactants such as CTAB, SDS and Tween had little effect on the fluorescence intensity. This phenomenon may be ascribed to the fact that PPEA and TX-100 share the same long aliphatic carbon tail. The hydrophobic interaction between PPEA and TX-100 might reduce the conformational disorder of PPEA and induce the PPEA chains to become more extended. Also, the effects of the amount of THF, the concentration of PPEA, pH, reaction time and coexisted materials on the determination were investigated. Under the optimum conditions, the fluorescence intensity was proportional to the concentration of Triton X-100 in the range of 0～200 and 200～700 μmol/L, respectively. And the concentration corresponding to the point of intersection of the two calibration graphs was found to be in good agreement with the critical micelle concentration (CMC) of Triton X-100. Therefore, a fluorescence enhancement method based on fluorescent conjugated polymer has been developed. It can be used to selectively detect Triton X-100 in the presence of other surfactants and indicate the CMC of Triton X-100. Two synthetic and three real Triton X-100 samples were determined with satisfactory results.

Key words: fluorescent conjugated polymer, triton X-100, critical micelle concentration (CMC)