title: Fluorescence Response of Conjugated Polyelectrolyte in an Immiscible Two-Phase System via Nonelectrostatic Interaction with Surfactants.
abstract: This paper reports a unique fluorescence (FL) response and diverse applications of conjugated polyelectrolyte (CPE) through nonelectrostatic interaction with appropriate (bio)surfactants in an immiscible two-phase system. A sulfonated microporous conjugated polymer (SMCP) with a conformation-variable intramolecular stacked structure was used as the CPE film. Despite the extremely high hydrophilicity, the SMCP film responded significantly to the hydrophobic circumstances, either physicochemically or electronically, in the presence of water-in-oil (w/o)-type nonionic surfactants with appropriate hydrophile-lipophile balance (HLB) values. The polymer film became fully wet with hydrophobic solvents due to the addition of small amounts of (bio)surfactant to reveal remarkable FL emission enhancement and chromism. Microcontact and inkjet printing using the SMCP film (or SMCP-adsorbed paper) and the surfactant solution as substrate and ink, respectively, provided high-resolution FL images due to the distinctive surfactant-induced FL change (SIFC) characteristic. Moreover, the additional electrostatic interaction of SMCP film with oppositely charged surfactants further enhanced the FL emission. Our findings will help comprehensive understanding of the nonelectrostatic SIFC mechanism of CPEs and development of novel SIFC-active materials.
authors.affiliation: †School of Applied Chemical Engineering, Major in Polymer Science and Engineering, Kyungpook National University, 1370 Sankyuk-dong, Buk-ku, Daegu 702-701, Korea.
authors.forename: Beomsu Shin-Il
authors.initials: BS
authors.lastname: Kim
authors.affiliation: †School of Applied Chemical Engineering, Major in Polymer Science and Engineering, Kyungpook National University, 1370 Sankyuk-dong, Buk-ku, Daegu 702-701, Korea.
authors.forename: Young-Jae
authors.initials: YJ
authors.lastname: Jin
authors.affiliation: ‡Department of Materials Science and Engineering, Graduate School of Engineering, University of Fukui, Bunkyo 3-9-1, Fukui 910-8507, Japan.
authors.forename: Toshikazu
authors.initials: T
authors.lastname: Sakaguchi
authors.affiliation: §Reliability Assessment Center for Chemical Materials Korea Research Institute of Chemical Technology(KRICT) 141, Gajeong-ro, Yuseong-gu, Daejeon 305-600, Korea.
authors.forename: Wang-Eun
authors.initials: WE
authors.lastname: Lee
authors.affiliation: †School of Applied Chemical Engineering, Major in Polymer Science and Engineering, Kyungpook National University, 1370 Sankyuk-dong, Buk-ku, Daegu 702-701, Korea.
authors.forename: Giseop
authors.initials: G
authors.lastname: Kwak
keywords: conjugated polyelectrolyte; fluorescence; nonelectrostatic interaction; printing ink; surfactant