The effect of solvent quality on the chain morphology in solutions of poly(9,9′-dioctylfluorene)
The effect of solvent quality on the chain morphology in solutions of poly(9,9′-dioctylfluorene)
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DOI：
10.1016/j.polymer.2007.02.047
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发表时间：
2007-04
期刊：
影响因子：
4.6
通讯作者：
C. Kitts;D. Bout
中科院分区：
文献类型：
--
作者：
C. Kitts;D. Bout
采用紫外-可见吸收光谱、差示扫描量热法、荧光光谱、原子力显微镜和近场扫描光学显微镜研究了聚（9，9 ′-二辛基芴）在不同溶剂中的α（α）相向β（β）相转变的热力学.结果表明，溶剂质量对α-构象转变为β-构象有很大影响。的趋势在crystalpies和转变温度表明，在较低的温度下链崩溃后，从增加的分子内相互作用的过渡结果。这种转变导致随后的凝胶化和/或聚集，其在较高温度下稳定β相并导致转变温度的大滞后。对于甲苯溶液，从聚集的β相转变为完全溶剂化的α相的焓为21.04kJmol− 1单体。测量的热量和以前报道的差异进行了讨论。
The thermodynamics of the alpha (α) phase to beta (β) phase transition was investigated in solution of poly(9,9′-dioctylfluorene) in a variety of solvents with UV–vis absorption spectroscopy, differential scanning calorimetry, fluorescence spectroscopy, atomic force microscopy, and near-field scanning optical microscopy. The results show that the solvent quality has a strong affect on the α- to β-conformational change. The trend in enthalpies and transition temperatures indicates that the transition results from an increase in intramolecular interactions upon chain collapse at lower temperatures. This transition leads to subsequent gelation and/or aggregation that stabilizes the β-phase at higher temperatures and leads to a large hysteresis in the transition temperature. The enthalpy for the transition from an aggregated β-phase to a fully solvated α-phase is found to be 21.04kJmol−1of monomer for toluene solutions. Differences between the measured heat and those previously reported are discussed.