Molecular Design and Characterization of Chromic Polyfluorene Derivatives

Blondin, Pierre; Bouchard, Julie; Beaupré, Serge; Belletête, Michel; Durocher, Gilles; Leclerc, Mario

doi:10.1021/ma000020l

Cited by 112 publications

(110 citation statements)

References 49 publications

Supporting

Mentioning

101

Contrasting

Order By: Relevance

“…As discussed in related studies on the interaction between this conjugated polyelectrolyte and gemini surfactants in aqueous solutions, 13f we believe that a sensitive balance between hydrophobic and hydrophilic effects is involved in the interaction of cosolvents, surfactants, and water-soluble polymers with the conjugated polyelectrolyte PBS-PFP. In addition, since conformational changes of the relatively flexible fluorene-phenylene backbone 60 may be involved in the solvent effect on the emission maxima, the rigidity of the microenvironment in the region of the chromophore may also play a role.…”

Section: Resultsmentioning

confidence: 99%

Solubilization of Poly{1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl} in Water by Nonionic Amphiphiles

et al. 2009

View full text Add to dashboard Cite

In the presence of the nonionic alkyloxyethylene surfactant n-dodecylpentaoxyethylene glycol ether (C 12 E 5 ), the anionic conjugated polyelectrolyte (CPE) poly{1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl} (PBS-PFP) dissolves in water, leading to a blue shift in fluorescence and dramatic increases in fluorescence quantum yields above the surfactant critical micelle concentration (cmc). No significant changes were seen with a poly(ethylene oxide) of similar size to the surfactant headgroup, confirming that specific surfactant-polyelectrolyte interactions are important. From UV-visible and fluorescence spectroscopy, dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), cryogenic transmission electron microscopy (cryo-TEM), and electrical conductivity, together with our published NMR and small-angle neutron scattering (SANS) results, we provide a coherent model for this behavior in terms of breakup of PBS-PFP clusters through polymer-surfactant association leading to cylindrical aggregates containing isolated polymer chains. This is supported by molecular dynamics simulations, which indicate stable polymer-surfactant structures and also provide indications of the tendency of C 12 E 5 to break up polymer clusters to form these mixed polymer-surfactant aggregates. Radial electron density profiles of the cylindrical cross section obtained from SAXS results reveal the internal structure of such inhomogeneous species. DLS and cryo-TEM results show that at higher surfactant concentrations the micelles start to grow, possibly partially due to formation of long, threadlike species. Other alkyloxyethylene surfactants, together with poly(propylene glycol) and hydrophobically modified poly(ethylene glycol), also solubilize this polymer in water, and it is suggested that this results from a balance between electrostatic (or ion-dipole), hydrophilic, and hydrophobic interactions. There is a small, but significant, dependence of the emission maximum on the local environment.

show abstract

Section: Resultsmentioning

confidence: 99%

Solubilization of Poly{1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl} in Water by Nonionic Amphiphiles

et al. 2009

View full text Add to dashboard Cite

show abstract

“…Since the first indication by Bradley et al, 2 other reports have shown a correlation between the intensity of this red-shifted peak and the poorsolvent content in solutions of good-solvent/poor-solvent mixtures (chloroform/methanol). 4,16 Furthermore, it has been suggested that octyl side chains in PFO are particularly effective at inducing and stabilizing such intramolecular ordering in solution, when compared to hexyl and dodecyl side groups. 7,10 The concept of side chain-driven planarization upon polymer agglomeration in solvent mixtures due to an increase of the fraction of a poor-solvent was also introduced.…”

Section: Introductionmentioning

confidence: 99%

Kinetics and Thermodynamics of Poly(9,9-dioctylfluorene) β-Phase Formation in Dilute Solution

et al. 2006

View full text Add to dashboard Cite

Poly(9,9-dioctylfluorene) (PFO) adopts a particular type of conformation in dilute solutions of the poor solvent methylcyclohexane (MCH) below 273 K, which is revealed by the appearance of a red-shifted absorption peak at 437-438 nm. The formation of this ordered conformation depends on the temperature but is independent of polymer concentration over the range studied (3-25 µg/mL). On the basis of absorption, steadystate, and time-resolved fluorescence data, the new absorption peak at 437-438 nm is assigned to a highly ordered conformation of PFO chains, analogous to the so-called -phase first identified in PFO films. From the study of PFO solutions in MCH as a function of temperature, we conclude that these ordered segments ( -conformation) coexist with less ordered domains in the same chain. When the ordered domains are present, they act as efficient energy traps and the fluorescence from the disordered regions is quenched. The transition between the disordered and the ordered PFO conformations is adequately described by a mechanism that involves two steps: a first, essentially intramolecular, one from a relatively disordered (R) to an ordered conformation ( ), followed by aggregation of chains containing -conformation into anisotropic ordered domains. From the temperature dependence of the 437-438 nm peak intensity, the transition temperature T ) 261 K, enthalpy ∆H ) -18.0 kcal mol -1 , and entropy ∆S ) -68.4 cal K -1 mol -1 were obtained. The formation of the -conformation domains were also followed as a function of time at 260 K. The rate constants at 260 K were determined, showing an order of magnitude around 10 -3 s -1 (k Rf ) 5.9 × 10 -4 s -1 ; k fR ) 9 × 10 -4 s -1 ; k agg ) 2.3 × 10 -3 M -1 s -1 ; k diss ) 4.4 × 10 -4 s -1 ). This small magnitude explains the long times required for a "complete" conversion to the -conformation.

show abstract

“…The absorption spectra of the 3,9-PFCz copolymer consist of one absorption peak at around 365 nm both in THF solution and thin solid film. We notice that the onset of the absorption peak of copolymer blueshifted 20 nm than that of polyfluorene homopolymer (384 nm), [22] suggesting decrease of conjugation length due to the local disorder induced by the presence of 9-(9,9-dioctyl-9H-fluoren-7-yl)-9H-carbazole kinked linkages. As shown in Figure 3, copolymer in THF solution has a PL emission peak at around 407 with vibronic shoulder at 427 nm.…”

Section: Optical Propertiesmentioning

confidence: 87%

Extremely Color‐Stable Blue Light‐Emitting Polymers Based on Alternating 2,7‐Fluorene‐co‐3,9‐carbazole Copolymer

Liu

Xiong

Zeng

et al. 2007

Macro Chemistry & Physics

View full text Add to dashboard Cite

Novel alternating 2,7‐fluorene‐co‐3,9‐carbazole copolymer(3,9‐PFCz) was synthesized by Suzuki polycondensation between 3‐bromo‐9‐(2‐iodo‐9,9‐dioctyl‐9H‐fluoren‐7‐yl)‐9H‐carbazole and 2,7‐bis(4,4,5,5‐tetramethyl‐1,3,2‐dioxaborolan‐2‐yl)‐9,9‐dioctylfluorene. Cyclic voltammetry studies showed a higher HOMO level (−5.23 eV) than the polyfluorene homopolymer(PFO). The glass transition temperature of the copolymer (110 °C) was much higher than that of the PFO (67 °C). After the copolymer had been annealed at 200 °C for 2 h, the PL spectra showed almost no change and no aggregation‐ or oxidation‐related undesirable long‐wavelength emission has been observed. The light‐emitting diode in configuration of ITO/PEDOT/EML/CsF/Al showed a maximum external quantum efficiency of 1.54% with a luminance of 435 cd · m−2 and the maximum brightness of 2 630 cd · m−2 with CIE coordinate (0.17, 0.14) was achieved at 8.4 V. The device prepared in configuration of ITO/PEDOT/PVK/polymer/Ba/Al exhibits an efficient, stable blue emission; it has a turn‐on voltage of 6 V and maximum external quantum efficiency of 1.1%. The EL emission remains stable at high current density and after thermal treatment at 150 °C for 30 min. Extremely color‐stable blue emission from alternating poly[(2,7‐fluorene)‐co‐(3,9‐carbazole)] copolymer makes it a promising candidate for flat‐panel display applications.magnified image

show abstract

Molecular Design and Characterization of Chromic Polyfluorene Derivatives

Cited by 112 publications

References 49 publications

Solubilization of Poly{1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl} in Water by Nonionic Amphiphiles

Solubilization of Poly{1,4-phenylene-[9,9-bis(4-phenoxy-butylsulfonate)]fluorene-2,7-diyl} in Water by Nonionic Amphiphiles

Kinetics and Thermodynamics of Poly(9,9-dioctylfluorene) β-Phase Formation in Dilute Solution

Extremely Color‐Stable Blue Light‐Emitting Polymers Based on Alternating 2,7‐Fluorene‐co‐3,9‐carbazole Copolymer

Contact Info

Product

Resources

About