title: A pH-responsive molecular switch with tricolor luminescence.
abstract: We developed a new ratiometric pH sensor based on poly(N-phenylmaleimide) (PPMI)-containing block copolymer that emits three different fluorescent colors depending on the pH. The strong solvatochromism and tautomerism of the PPMI derivatives enabled precise pH sensing for almost the entire range of the pH scale. Theoretical calculations have predicted largely dissimilar band gaps for the keto, enol, and enolate tautomers of PPMI owing to low-dimensional conjugation effects. The tunable emission wavelength and intensity of our sensors, as well as the reversible color switching with high-luminescent contrast, were achieved using rational molecular design of PPMI analogues as an innovative platform for accurate H(+) detection. The self-assembly of block copolymers on the nanometer length scale was particularly highlighted as a novel prospective means of regulating fluorescence properties while avoiding the self-quenching phenomenon, and this system can be used as a fast responsive pH sensor in versatile device forms.
authors.affiliation: Department of Chemistry and ‡Division of Advanced Materials Science, Pohang University of Science and Technology , Pohang 790-784, Korea.
authors.forename: Hyungmin
authors.initials: H
authors.lastname: Ahn
authors.forename: Jaewan
authors.initials: J
authors.lastname: Hong
authors.forename: Sung Yeon
authors.initials: SY
authors.lastname: Kim
authors.forename: Ilyoung
authors.initials: I
authors.lastname: Choi
authors.forename: Moon Jeong
authors.initials: MJ
authors.lastname: Park
mesh_terms: D015374:Biosensing Techniques; D002713:Chlorine / Q000737:chemistry; D004581:Electronics; D004583:Electrons; D005456:Fluorescent Dyes / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D049449:Luminescence; D009682:Magnetic Resonance Spectroscopy; D008301:Maleimides / Q000737:chemistry*; D008823:Micelles; D046529:Microscopy, Electron, Transmission; D008856:Microscopy, Fluorescence; D009991:Oscillometry; D011092:Polyethylene Glycols / Q000737:chemistry; D011108:Polymers / Q000737:chemistry; D011522:Protons; D012997:Solvents / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet; D055672:Static Electricity; D014867:Water / Q000737:chemistry
chemical_list: D005456:Fluorescent Dyes; D008301:Maleimides; D008823:Micelles; D011108:Polymers; D011522:Protons; D012997:Solvents; D014867:Water; D011092:Polyethylene Glycols; D002713:Chlorine; C028210:monomethoxypolyethylene glycol
keywords: fluorescence; multicolor luminescence; pH sensors; ratiometric; self-assembly; tautomerism