title: Aqueous solution behavior of anionic fluorene-co-thiophene-based conjugated polyelectrolytes.
abstract: Two anionic fluorene-thiophene alternating copolymers, poly[9,9-bis(4-sulfonylbutoxyphenyl)fluorene-2,7-diyl-2,5-thienylene] (PBS-PFT) and poly[9,9-bis(4-sulfonylbutoxyphenyl)fluorene-2,7-diyl-2,2'-bithiophene-5,5'-diyl] (PBS-PF2T), have been synthesized and their solution behaviors in water studied by UV-vis absorption spectroscopy, fluorescence, and electrical conductivity and compared with that of the previously studied conjugated polyelectrolyte (CPE) poly[9,9-bis(4-sulfonylbutoxyphenyl)fluorene-2,7-diyl-1,4-phenylene] (PBS-PFP). These conjugated polymers do not form solutions at the molecular level in water but instead form clusters. Information on the structure of these clusters for PBS-PF2T comes from small-angle X-ray and neutron scattering. The relative ease of dispersing the copolymers in water increases with an increase in the number of thiophene rings in these alternating copolymers. Semiempirical calculations on the structure suggest that this results from bending of the chains and increased conformational flexibility, decreasing interchain interactions. These CPEs can be dissolved in water at the molecular level using the nonionic surfactants n-dodecylpentaoxyethylene glycol ether (C12E5) or Triton X-100 to obtain systems with increased photoluminescence quantum yield and increased electrical conductivity that can be solution-processed for potential applications as components of sensory or optoelectronic devices.
authors.affiliation: Departamento de Quimica and Centro de Neurociencias e Biologia Celular, Universidade de Coimbra, 3004-535 Coimbra, Portugal. burrows@ci.uc.pt
authors.forename: Hugh D
authors.initials: HD
authors.lastname: Burrows
authors.forename: María J
authors.initials: MJ
authors.lastname: Tapia
authors.forename: Sofia M
authors.initials: SM
authors.lastname: Fonseca
authors.forename: Artur J M
authors.initials: AJ
authors.lastname: Valente
authors.forename: Victor M M
authors.initials: VM
authors.lastname: Lobo
authors.forename: Licínia L G
authors.initials: LL
authors.lastname: Justino
authors.forename: Song
authors.initials: S
authors.lastname: Qiu
authors.forename: Swapna
authors.initials: S
authors.lastname: Pradhan
authors.forename: Ullrich
authors.initials: U
authors.lastname: Scherf
authors.forename: Nitin
authors.initials: N
authors.lastname: Chattopadhyay
authors.forename: Matti
authors.initials: M
authors.lastname: Knaapila
authors.forename: Vasil M
authors.initials: VM
authors.lastname: Garamus