Aggregation Properties of Conjugated Polyelectrolytes

Knaapila, Matti; Fonseca, Sofia M.; Costa, Telma

doi:10.1002/9783527655700.ch4

Cited by 13 publications

(14 citation statements)

References 89 publications

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“…Conjugated polyelectrolytes (CPEs) possess physical–chemical properties related to both “π” systems, like acting as chromophores and fluorophores, and properties of polyelectrolytes, such as solubility in high dielectric media (e.g., water and other polar solvents). They also possess the capability of coordination through electrostatic forces and hydrogen bonding (H-bonding) either with solvents, therefore helping in solubilization, or with other dissolved molecules. − The ionic groups in the polymers introduce ion–dipole and ion–ion forces …”

Section: Introductionmentioning

confidence: 99%

Cationic Imidazolium Polythiophenes: Effects of Imidazolium-Methylation on Solution Concentration-Driven Aggregation and Surface Free Energy of Films Processed from Solvents with Different Polarity

et al. 2020

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Cationic imidazolium-functionalized polythiophenes with single- or double-methylation of the imidazolium ring were used to study the impact of imidazolium-methylation on (i) the solution concentration-driven aggregation in the presence of paramagnetic probes with different ionic and hydrophobic constituents and (ii) their surface free energy (SFE) as spin-coated films deposited on plasma-activated glass. Electron paramagnetic resonance spectroscopy shows that the differences in film structuration between the polymers with different methylations originate from the early stages of aggregation. In the solid state, higher degree of imidazolium-methylation generates smaller values of total SFE, γ S , (by around 2 mN/m), which could be relevant in optoelectronic applications. Methylation also causes a decrease in the polar contribution of γ S (γS p ), suggesting that methylation decreases the polar nature of the imidazolium ring, probably due to the blocking of its H-bonding capabilities. The values of γ S obtained in the present work are similar to the values obtained for doped films of neutral conjugated polymers, such as polyaniline, poly(3-hexylthiophene), and polypyrrole. However, imidazolium-polythiophenes generate films with a larger predominance of the dispersive component of γ S (γS d ), probably due to the motion restriction in the ionic functionalities in a conjugated polyelectrolyte, in comparison to regular dopants. The presence of 1,4-dioxane increases γS p , especially, in the polymer with larger imidazolium-methylation (and therefore unable to interact through H-bonding), probably by a decrease of the imidazolium–glass interactions. Singly-methylated imidazolium polythiophenes have been applied as electrode selective (“buffer”) interlayers in conventional and inverted organic solar cells, improving their performance. However, clear structure–function guidelines are still needed for designing high-performance polythiophene-based interlayer materials. Therefore, the information reported in this work could be useful for such applications.

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Section: Introductionmentioning

confidence: 99%

Cationic Imidazolium Polythiophenes: Effects of Imidazolium-Methylation on Solution Concentration-Driven Aggregation and Surface Free Energy of Films Processed from Solvents with Different Polarity

et al. 2020

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Section: Introductionmentioning

confidence: 99%

“…It is also known that the distance between the charged group and the conjugated polymer backbone has an impact on water solubility and critical solution temperature and on the electronic properties of films of thiophene–zwitterions . On the other side, molecular dynamics simulations have shown that the spacer length of CPEs generates a fine balance between electrostatic and hydrophobic interactions with gemini surfactants. , …”

Section: Introductionmentioning

confidence: 99%

“…37 On the other side, molecular dynamics simulations have shown that the spacer length of CPEs generates a fine balance between electrostatic and hydrophobic interactions with gemini surfactants. 38,39 It is possible to gain information on the optical properties of CPEs by studying the effect of increasing concentrations on their spectral features because such an approach reveals information on (i) the processes occurring during absorption and emission, (ii) efficient excitation energy transfer between chromophores, and (iii) nonradiative (internal conversion) fluorescence decay, such as aggregation-driven self-quenching of fluorescence. The elucidation of the physical−chemical mechanisms responsible for this phenomenon is a prerequisite for a fundamental understanding of the photochemistry of conjugated polymers because correlating changes in emission spectra and the degree of self-quenching 40 provide information on the formation, number, and interaction pathways of chromophores.…”

Section: ■ Introductionmentioning

confidence: 99%

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Effect of Spacer Length and Solvent on the Concentration-Driven Aggregation of Cationic Hydrogen-Bonding Donor Polythiophenes

et al. 2018

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Aggregation of cationic isothiouronium polythiophenes with alkoxy-spacers of different lengths at the 3-position of the thiophene ring was studied in solvents of different polarities. Hydrogen-bonding capacity was assessed by steady-state absorption and fluorescence spectroscopy, whereas the aggregation in aqueous solutions was studied by electron paramagnetic resonance spectroscopy, using paramagnetic probes of different polarities. The two polymers displayed similar features in respect to conformation, effect of cosolvents on aggregation, unstructured absorption–fluorescence spectra, Stokes shifts when aggregated, solvatochromic effect, and self-quenching concentration. However, these polymers also showed different specific interactions with water, Stokes shifts in water, effect of the solvent on the extent of dominant state of the S1 level, and also different inner cavities and hydrophobic–hydrophilic surface area in aqueous solution aggregates. Water maximized the difference between the polymers concerning the effect of specific increases in concentration, whereas the presence of 1,4-dioxane generated almost identical effects on both polymers.

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“…CPEs are, however, generally subject to issues surrounding their solubility, are difficult to dissolve down to a single molecule level and have a propensity for aggregation without precipitating [ 17 ]. Several approaches have been implemented to resolve this issue and, therefore, recover the favorable optical and electronic properties of CPEs.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Study of Self-Assembly of Aqueous Solutions of Poly[9,9-bis(4-Sulfonylbutoxyphenylphenyl) Fluorene-2,7-diyl-2,2’-Bithiophene] (PBS-PF2T) in the Presence of Pentaethylene Glycol Monododecyl Ether (C12E5)

Stewart

2016

Materials

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Results are presented using molecular dynamics (MD) of the self-assembly of the conjugated polyelectrolyte poly[9,9-bis(4-sulfonylbutoxyphenylphenyl) fluorene-2,7-diyl-2,2’-bithiophene] (PBS-PF2T) with 680 mM pentaethylene glycol monododecyl ether (C12E5) in water. Simulations are used to examine the interaction between PBS-PF2T and C12E5 and suggest a break-up of PBS-PF2T aggregates in solution. These systems are dominated by the formation of cylindrical phases at temperatures between 0 °C and 20 °C and also between 45 °C and 90 °C. More diffuse phases are seen to occur between 20 °C and 45 °C and also above 90 °C. Simulations are related to previous computational and experimental studies on PBS-PF2T aggregation in the presence of tetraethylene glycol monododecyl ether (C12E4) in bulk and thin films.

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Aggregation Properties of Conjugated Polyelectrolytes

Cited by 13 publications

References 89 publications

Cationic Imidazolium Polythiophenes: Effects of Imidazolium-Methylation on Solution Concentration-Driven Aggregation and Surface Free Energy of Films Processed from Solvents with Different Polarity

Cationic Imidazolium Polythiophenes: Effects of Imidazolium-Methylation on Solution Concentration-Driven Aggregation and Surface Free Energy of Films Processed from Solvents with Different Polarity

Effect of Spacer Length and Solvent on the Concentration-Driven Aggregation of Cationic Hydrogen-Bonding Donor Polythiophenes

Molecular Dynamics Study of Self-Assembly of Aqueous Solutions of Poly[9,9-bis(4-Sulfonylbutoxyphenylphenyl) Fluorene-2,7-diyl-2,2’-Bithiophene] (PBS-PF2T) in the Presence of Pentaethylene Glycol Monododecyl Ether (C12E5)

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