کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5185985 1381092 2007 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The effect of solvent quality on the chain morphology in solutions of poly(9,9′-dioctylfluorene)
موضوعات مرتبط
مهندسی و علوم پایه شیمی شیمی آلی
پیش نمایش صفحه اول مقاله
The effect of solvent quality on the chain morphology in solutions of poly(9,9′-dioctylfluorene)
چکیده انگلیسی

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 21.04 kJ mol−1 of monomer for toluene solutions. Differences between the measured heat and those previously reported are discussed.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Polymer - Volume 48, Issue 8, 5 April 2007, Pages 2322-2330
نویسندگان
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