Gelation behavior of poly(9,9-dioctylfluorene)/poly[9,9-di(2-ethylhexyl)- fluorenyl-2,7-diyl] blend in methylcyclohexane solutions

Jean Hong Chen*, Ching Iuan Su, Hsin Lung Chen, Chih Shun Chang, Yu Chun Chang, Lung Chuan Chen, Show An Chen

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

1 Scopus citations


We investigated the gelation behavior of the blend of two light-emitting polyfluorenes, i.e., poly(9,9-dioctylfluorene-2,7-diyl) (PF8) and poly[9,9-di(2-ethylhexyl)-fluorenyl-2,7-diyl] (PF2/6), in solutions with methylcyclohexane (MCH). Upon prolonged aging at room temperature, dynamic light scattering revealed that phase separation in the initially well-mixed solutions occurred via spinodal decomposition, yielding a PF8/PF 2/6-enriched phase and an isotropic solvent-rich phase. Sheetlike aggregates in which a portion of the PF8 chains adopted the β conformation were formed in the polymer-enriched phase, as revealed by small-angle X-ray scattering and optical spectroscopy. Macroscopically, the phase separation transformed the original viscous liquid solution into a gel. Measurements of the gelation temperature (Tgel), gel-to-sol transition temperature (Tg-s), and spinodal decomposition temperature (TSD) indicated that gelation (and hence phase separation) became more difficult with increasing content of PF2/6. The presence of PF2/6 also hindered formation of the β-phase of PF8. Therefore, the microstructure and photophysical properties of PF 8/PF2/6 in MCH solution can be tuned by the composition of the two polymers.

Original languageEnglish
Pages (from-to)17457-17464
Number of pages8
Issue number50
StatePublished - 18 12 2012
Externally publishedYes


Dive into the research topics of 'Gelation behavior of poly(9,9-dioctylfluorene)/poly[9,9-di(2-ethylhexyl)- fluorenyl-2,7-diyl] blend in methylcyclohexane solutions'. Together they form a unique fingerprint.

Cite this