Novel Multifunctional Luminescent Electrospun Fluorescent Nanofiber Chemosensor-Filters and Their Versatile Sensing of pH, Temperature, and Metal Ions

Bo-Yu Chen; Yen-Chen Lung; Chi-Ching Kuo; Fang-Cheng Liang; Tien-Liang Tsai; Dai-Hua Jiang; Toshifumi Satoh; Ru-Jong Jeng

doi:10.3390/polym10111259

Novel Multifunctional Luminescent Electrospun Fluorescent Nanofiber Chemosensor-Filters and Their Versatile Sensing of pH, Temperature, and Metal Ions

Polymers (Basel). 2018 Nov 13;10(11):1259. doi: 10.3390/polym10111259.

Authors

Bo-Yu Chen^{1

2}, Yen-Chen Lung³, Chi-Ching Kuo^{4

5}, Fang-Cheng Liang⁶, Tien-Liang Tsai⁷, Dai-Hua Jiang⁸, Toshifumi Satoh⁹, Ru-Jong Jeng^{10

11}

Affiliations

¹ Institute of Polymer Science and Engineering, National Taiwan University, 106 Taipei, Taiwan. leodapon@gmail.com.
² Institute of Organic and Polymeric Materials, National Taipei University of Technology, 10608 Taipei, Taiwan. leodapon@gmail.com.
³ Institute of Organic and Polymeric Materials, National Taipei University of Technology, 10608 Taipei, Taiwan. iduo1125@hotmail.com.
⁴ Institute of Organic and Polymeric Materials, National Taipei University of Technology, 10608 Taipei, Taiwan. kuocc@mail.ntut.edu.tw.
⁵ Research and Development Center for Smart Textile Technology, National Taipei University of Technology, 10608 Taipei, Taiwan. kuocc@mail.ntut.edu.tw.
⁶ Institute of Organic and Polymeric Materials, National Taipei University of Technology, 10608 Taipei, Taiwan. frank62112003@yahoo.com.tw.
⁷ Institute of Organic and Polymeric Materials, National Taipei University of Technology, 10608 Taipei, Taiwan. x1x2x310@gmail.com.
⁸ Institute of Organic and Polymeric Materials, National Taipei University of Technology, 10608 Taipei, Taiwan. asdf8289@yahoo.com.tw.
⁹ Graduate School of Chemical Sciences and Engineering and Faculty of Engineering, Hokkaido University, Sapporo 060-8628, Japan. satoh@eng.hokudai.ac.jp.
¹⁰ Institute of Polymer Science and Engineering, National Taiwan University, 106 Taipei, Taiwan. rujong@ntu.edu.tw.
¹¹ Advanced Research Center for Green Materials Science and Technology, National Taiwan University, 106 Taipei, Taiwan. rujong@ntu.edu.tw.

Abstract

Novel multifunctional fluorescent chemosensors composed of electrospun (ES) nanofibers with high sensitivity toward pH, mercury ions (Hg²⁺), and temperature were prepared from poly(N-Isopropylacrylamide-co-N-methylolacrylamide-co-rhodamine derivative) (poly(NIPAAm-co-NMA-co-RhBN2AM)) by employing an electrospinning process. NIPAAm and NMA moieties provide hydrophilic and thermo-responsive properties (absorption of Hg²⁺ in aqueous solutions), and chemical cross-linking sites (stabilization of the fibrous structure in aqueous solutions), respectively. The fluorescent probe, RhBN2AM is highly sensitive toward pH and Hg²⁺. The synthesis of poly(NIPAAm-co-NMA-co-RhBN2AM) with different compositions was carried on via free-radical polymerization. ES nanofibers prepared from sensory copolymers with a 71.1:28.4:0.5 NIPAAm:NMA:RhBN2AM ratio (P3 ES nanofibers) exhibited significant color change from non-fluorescent to red fluorescence while sensing pH (the λ_{PL, max} exhibited a 4.8-fold enhancement) or Hg²⁺ (at a constant Hg²⁺ concentration (10^-3 M), the λ_{PL, max} of P3-fibers exhibited 4.7-fold enhancement), and high reversibility of on/off switchable fluorescence emission at least five times when Hg²⁺ and ethylenediaminetetraacetic acid (EDTA) were sequentially added. The P3 ES nanofibrous membranes had a higher surface-to-volume ratio to enhance their performance than did the corresponding thin films. In addition, the fluorescence emission of P3 ES nanofibrous membranes exhibited second enhancement above the lower critical solution temperature. Thus, the ES nanofibrous membranes prepared from P3 with on/off switchable capacity and thermo-responsive characteristics can be used as a multifunctional sensory device for specific heavy transition metal (HTM) in aqueous solutions.

Keywords: chemosensor; electrospun nanofibers; mercury ion; pH; thermo-response.