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Self‐Assembly and Molecular Dynamics of Oligoindenofluorenes
Author(s) -
Elmahdy Mahdy M.,
Floudas George,
Oldridge Luke,
Grimsdale Andrew C.,
Müllen Klaus
Publication year - 2006
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.200600015
Subject(s) - differential scanning calorimetry , relaxation (psychology) , photoluminescence , glass transition , materials science , chemical physics , dielectric , arrhenius equation , liquid crystal , chemistry , polymer , crystallography , activation energy , thermodynamics , optoelectronics , composite material , psychology , social psychology , physics
10.1002/cphc.200600015.abs The optical properties, self‐assembly mechanism, thermal properties, and the associated molecular dynamics of a series of stable blue‐emitting oligoindenofluorenes up to the polymer were investigated by photoluminescence, wide‐angle X‐ray scattering, polarizing optical microscopy, differential scanning calorimetry, and dielectric spectroscopy. Oligomers of indenofluorenes possess high structural order and form smectic mesophases, as opposed to the nematic mesophases formed in the corresponding oligofluorenes. The α process associated with the liquid‐to‐glass transition displays an asymmetric broadening of relaxation times (non‐Debye process), with a non‐Arrhenius temperature dependence of relaxation times and a strong molecular weight dependence. The low dielectric loss and low ionic conductivity revealed the absence of ketone structural defects, which is consistent with the observed stable blue emission.