Aqueous solution behavior of anionic fluorene-co-thiophene-based conjugated polyelectrolytes

Area of Science:

• Polymer Chemistry
• Materials Science
• Nanotechnology

Background:

• Anionic fluorene-thiophene alternating copolymers are novel conjugated polyelectrolytes (CPEs).
• Understanding their solution behavior in water is crucial for developing new materials.
• Previous studies focused on poly[9,9-bis(4-sulfonylbutoxyphenyl)fluorene-2,7-diyl-1,4-phenylene] (PBS-PFP).

Purpose of the Study:

• To synthesize and characterize two new fluorene-thiophene alternating copolymers: PBS-PFT and PBS-PF2T.
• To investigate the solution behavior of these copolymers in water.
• To compare their properties with PBS-PFP and explore potential applications.

Main Methods:

• Synthesis of PBS-PFT and PBS-PF2T copolymers.
• UV-vis absorption spectroscopy, fluorescence, and electrical conductivity measurements.
• Small-angle X-ray and neutron scattering for structural analysis.
• Semiempirical calculations for conformational analysis.

Main Results:

• PBS-PFT and PBS-PF2T form clusters in water, not molecular solutions.
• Increased thiophene content enhances copolymer dispersibility in water.
• Semiempirical calculations indicate chain bending and flexibility reduce interchain interactions.
• Surfactants (C12E5, Triton X-100) enable molecular dissolution, boosting photoluminescence and conductivity.

Conclusions:

• The dispersibility of fluorene-thiophene copolymers in water is tunable by altering the thiophene content.
• Surfactant-assisted dissolution yields processable CPEs with enhanced optoelectronic properties.
• These materials show promise for applications in sensory and optoelectronic devices.