磺酸型聚芴的合成及性能

Synthesis and Properties of Sulfonate Polyfluorenes

利用迈克尔加成反应合成了2,7-二溴-9,9-二-(3-丙基酰胺-2-甲基丙磺酸)芴单体,并通过Suzuki偶合反应制备了含不同磺酸比例的磺酸型聚芴(PF6SO3H)。通过核磁共振氢谱、凝胶渗透色谱、溶解性试验、紫外吸收光谱、荧光发射光谱、循环伏安曲线及热重分析法对聚合物结构和性能进行了表征分析。结果表明,成功合成了相对分子质量在3万~5万之间的磺酸型聚芴。发现随着磺酸型聚芴中磺酸基团含量的不同,聚合物在甲醇溶液中的溶解度不同,含有50%磺酸基团的PF6SO3H在甲醇中的溶解度达到了18mg/mL。磺酸侧链的引入使聚芴在薄膜状态和溶液状态下的紫外吸收最大吸收峰和最大荧光发射峰较聚(9,9-二己基)芴(PF6)发生了9nm^40nm红移,且能带隙逐渐变窄,同时磺酸型聚芴的HOMO较PF6增大。热失重分析发现磺酸侧链的引入,使得磺酸型聚芴的热稳定性较PF6有一定的下降。

A monomer,(2,7-dibromo-9,9-bis(3-propylamide-2-methylpropane sulfonic acid))fluorene(FSO3H),was synthesized by Michael addition reaction,and sulfonate polyfluorenes(PF6SO3H)with different amounts of sulfonic acid group were synthesized by Suzuki reaction.The structure and properties of polymers were investigated by 1 H-NMR,gel permeation chromatography(GPC),solution test,UV-visible absorption spectroscopy,photoluminescence spectroscopy,cyclic voltammetry(CV)and thermal gravimetric analysis(TGA).The results show that sulfonate polyfluorenes with珨Mnof 30000 to 50000were successfully synthesized.Polyfluorenes with different amounts of sulfonic acid group show good solubilities in methanol.The solubility of PF6SO3 H containing 50%sulfonic acid group in methanol is up to 18mg/mL.When sulfonic acid side chains were introduced,the UV-visible absorption and the photoluminance spectra of the polyfluorenes show a red shift of about 9~40nm relative to PF6,both in solution and solid film state.And the band gap becomes narrower compared with that of PF6.The sulfonate polyfluorenes show higher HOMO energy level than PF6.TGA analysis reveals the introduction of sulfonic acid side chains into polyfluorene lowers thermostability of the polymers.