title: Smart Fluorescent Nanoparticles in Water Showing Temperature-Dependent Ratiometric Fluorescence Color Change.
abstract: We synthesized two different amphiphilic small molecules 1 and 2 by attaching the same oligo(ethylene glycol) (OEG) unit to the same dicyanodistyrylbenzene (DCS) fluorophore but at different positions. These molecules self-assemble into nanoparticles in water and show lower critical solution temperature (LCST) at 26 and 58 °C, respectively. Upon heating, the transition of hydrophilic coils to hydrophobic globules of the OEG unit leads to the change in the stacking structure of the luminescent DCS cores. As a result, it shows significant ratiometric fluorescence color changes from excimeric yellow emission to monomer-dominated green emission. Interestingly, the coassembly of 1 and 2 exhibits single transition temperature between the transition temperatures of the two components. Moreover, it is demonstrated that the transition temperature of the coassembly is delicately tuned over 26-58 °C by varying the molar mixing ratio of them.
authors.affiliation: Center for Supramolecular Optoelectronic Materials, Department of Materials Science and Engineering, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea.
authors.forename: Junjie
authors.initials: J
authors.lastname: Cui
authors.affiliation: Center for Supramolecular Optoelectronic Materials, Department of Materials Science and Engineering, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea.
authors.forename: Ji Eon
authors.identifier: http://orcid.org/0000-0001-5382-3690
authors.initials: JE
authors.lastname: Kwon
authors.affiliation: Center for Supramolecular Optoelectronic Materials, Department of Materials Science and Engineering, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea.
authors.forename: Hyeong-Ju
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Center for Supramolecular Optoelectronic Materials, Department of Materials Science and Engineering, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea.
authors.forename: Dong Ryeol
authors.initials: DR
authors.lastname: Whang
authors.affiliation: Center for Supramolecular Optoelectronic Materials, Department of Materials Science and Engineering, Seoul National University , 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Korea.
authors.forename: Soo Young
authors.initials: SY
authors.lastname: Park
keywords: LCST; amphiphilic; ratiometric fluorescence switching; self-assembly; supramolecular chemistry