| In this paper, four conjugated polymers were prepared using fluorene and benzene as the main chain, through Suzuki coupling:polyfluorene with propyl bromide PF-b, polyfluorene with mercaptoacetic acid side chain PF-1, polyfluorene with sodium thioglycolate PF-1Na, and polyfluorene with methionine side chain PF-2. We investigated their solubility in common solvents and fluorescence properties to filter out a good water-soluble fluorescent polymer. Then we studied the sensory properties of PF-1Na and its combination with quantum dots luminescence particularly.Firstly, we synthesized the monomer 2,7-dibromo-9,9-bis(3-bromopropyl)fluorene, and investigated certain synthesis conditions about the compound. It was found that Brij-58 emulsifier effectively accelerated the reaction of 2,7-dibromofluorene and 1,3-dibromopane in KOH aqueous solution. The optimized reaction conditions:0.01 eq. Brij-58,10 min,25℃,77 eq. KOH.Next, we synthesized PF-b by Suzuki coupling reaction, subsequently modified it with different functional groups such as mercaptoacetic acid and methionine, and obtained polymer PF-1, PF-1Na and PF-2. Then we characterized the polymers by GPC, IR. PF-1Na has good solubility in water,0.5 mg/mL. PF-2 has very poor solubility in THF, and is not soluble in other common solvents. To examine their thermal stability, we used TGA test analysis. The results showed that thermal stability of the modified polymers have some variations compared with PF-b, but they still have good thermal stability before 200℃, which makes them promising materials in the field of fluorescent sensing.In different solvents, PF-b, PF-1, PF-1Na and PF-2 have different fluorescence quantum yield. PF-b gets 71% in chloroform, PF-1Na 69% in water.Literature which reported the similar structures with PF-1Na, its fluorescence quantum yield was 0.59 in the pH 8.9 buffer solution, lower than the material we prepared. In addition, because the pH of water solution will influence the charge amount of the carboxylic acid salt polymer, the absorption and PL spectrum of the carboxylic acid salt should be pH-dependence. Subsequently we examined its fluorescence spectra at different pH values. Results indicate that before and after pH 7, there are two different spectra, and its spectrum intensity is stronger in alkaline aqueous solution. Carboxylate and sulfhydryl have certain complexation with many metal ions. Thus we examined the sensory properties of PF-1Na. And research shows PF-lNa has different sensitivity to trivalent ions Al3+ and Fe3+ in high and low concentrations, respectively. At low concentrations(1.0×10-5M), PF-1Na is more sensitive to Al3+ over Fe3+, while in high concentrations(1.5×10-4M), it is more sensitive to Fe3+. Furthermore, PF-1Na also has some fluorescence selectivity for Hg2+The luminescence band of water-soluble QDs generally rang from green to red. We further investigated the combination of PF-1Na and water-soluble QDs. As the results shown, the addition of a certain amount PF-1Na to the reaction can promote the growth of quantum dots, The fluorescence quantum reaches to 40%. And a certain amount of PF-1Na physically combined with multicolor QDs can emit white light, which makes it a promising material in the field of LED white light-emitting.
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