C β conformer formation in poly(9,9-dioctylfluorene) single chains facilitated by endcapping with an electron deficient moiety

• Published in: RSC advances 2014, Vol.4 (28), p.14365-14368
• Main Authors: Chen, Pei-Yin, Rassamesard, Areefen, Hung, Ming-Chin, Chen, Hsin-Lung, Chen, Show-An
• Format: Article
• Language: English
• ISSN: 2046-2069; 2046-2069
• DOI: 10.1039/C3RA46725B

Using single molecule spectroscopy, we demonstrate the enhancement of C β conformer formation in poly(9,9-dioctylfluorene) (PFO) at the single chain level by endcapping with the electron deficient moiety, triazole (TAZ) or oxadiazole (OXD). The single-chain photoemission spectra of PFO without endcapping (PFO u ) indicates that the addition of endcappers results in mixed contributions of both disordered and C β conformations. The as-cast endcappers are found to exhibit significantly larger amounts of C β emissions than as-cast PFO u . A higher population of C β conformers lead to better alignment of the chromophores in the polymer backbone, as demonstrated by the polarization modulation depth measurement. Our findings are consistent with the higher β-phase content in the thin films cast from the endcapped PFOs, which means that the intra-chain interaction mediated by EDM dominates the β-phase formation. The present study offers an important basis for a useful approach to increasing β-phase content based on endcapping PFO with TAZ or OXD without the need for further sample treatment.