Interactions between hairy rod anionic conjugated polyelectrolytes and nonionic alkyloxyethylene surfactants in aqueous solution: Observations from cloud point behaviour

Abstract

The effect of three anionic, hairy-rod fluorene based conjugated polyelectrolytes on the cloud points of the alkyloxyethylene surfactants C10E3, C12E4, C12E5, and C12E6 has been studied in aqueous solution. Although the association behaviour of these rigid polymers with surfactants is different from that of more flexible polyelectrolytes, both types of polymers are seen to increase the cloud points, probably as a consequence of associative interactions. The possible importance of Coulombic interactions is suggested by the decrease in cloud points with these systems in the presence of NaCl. With the conjugated polyelectrolytes, the effect appears to be most pronounced with poly[9,9-bis(4-phenoxybutylsulfonate)fluorene-co-2,5-thienylene], which may result from specific interactions between oxyethylene groups and the thiophene ring. The value of cloud point behaviour in designing water based formulations for preparation of devices of these conjugated polyelectrolytes is discussed.

Effects of Charge Density on Photophysics and Aggregation Behavior of Anionic Fluorene-Arylene Conjugated Polyelectrolytes

“…In the case of surfactants, this occurs in the region of the critical micelle concentration (cmc) [24,30,32]. Various factors appear to be involved in the formation and break-up of CPE aggregates [28,29,30,31,33,34], although, as of yet, there is no consensus as to the dominant interaction(s). Edman and co-workers have demonstrated, using pulse-field-gradient Nuclear magnetic resonance (NMR,) photoluminescence and Raman spectroscopy, that the CPE poly{9,9′-bis[6″-( N , N , N -trimethylammonium)-hexylfluorene- alt -1,4-phenylene] dibromide} forms aggregates in methanol [28]; they have also suggested that π,π interactions of backbones, coupled with electrostatic screening of ionic side chains by solvent, are important effects.…”

Nanostructuring of the conjugated polyelectrolyte poly[9,9-bis(4-sulfonylbutoxyphenyl)fluorene-2,7-diyl-2,2′-bithiophene] in liquid crystalline C12E4 in bulk water and aligned thin films

“…28 Indications that anionic CPEs may be incorporated within mesophases formed in the binary nonionic alkyloxyethylene surfactant-water systems come from their effects on the surfactant cloud points. 29 We have, therefore, looked at the possibility of nanostructuring these anionic CPEs to spontaneously form anisotropic lamellar phases using the C 12 E 4 -water system.…”

What conjugated polyelectrolytes tell us about aggregation in polyelectrolyte/surfactant systems

“…monomer unit [35]. Associative interaction between these conjugated polyelectrolytes and non-ionic surfactants is also reflected by changes in the cloud points [42]. As indicated above, ionic conjugated polyelectrolytes, such as these polyfluorenes, have a tendency to self-aggregate in poor solvents, like water.…”