A pyrene-functional polystyrene copolymer was prepared via 1,3-dipolar cycloaddition reaction (Sharpless-type click recation) between azide-functional styrene copolymer and 1-ethynylpyrene. Subsequently, nanofibers of pyrene-functional polystyrene copolymer were obtained by using electrospinning technique. The nanofibers thus obtained, found to preserve their parent fluorescence nature, confirmed the avoidance of aggregation during fiber formation. The trace detection of trinitrotoluene (TNT) in water with a detection limit of 5 nM was demonstrated, which is much lower than the maximum allowable limit set by the U.S. Environmental Protection Agency. Interestingly, the sensing performance was found to be selective toward TNT in water, even in the presence of higher concentrations of toxic metal pollutants such as Cd(2+), Co(2+), Cu(2+), and Hg(2+). The enhanced sensing performance was found to be due to the enlarged contact area and intrinsic nanoporous fiber morphology. Effortlessly, the visual colorimetric sensing performance can be seen by naked eye with a color change in a response time of few seconds. Furthermore, vapor-phase detection of TNT was studied, and the results are discussed herein. In terms of practical application, electrospun nanofibrous web of pyrene-functional polystyrene copolymer has various salient features including flexibility, reproducibility, and ease of use, and visual outputs increase their value and add to their advantage.

Novel hexa‐armed and pyrene (Pyr) end‐capped phosphazene dendrimer [N3P3‐(Pyr)6] and star polymer with poly(ε‐caprolactone) (PCL) arms [N3P3‐(PCL‐Pyr)6] were prepared via two series of reactions. In these series, core‐first approach was used starting from a hexa‐hydroxy functional phosphazene derivative (N3P3‐(OH)6). It was used as an initiator in the ring‐opening polymerization of ε‐caprolactone to prepare a hexa‐armed PCL star polymer (N3P3‐(PCL‐OH)6). Hydroxyl functionalities of N3P3‐(OH)6 and N3P3‐(PCL‐OH)6 were then successfully converted into bromide and azide, in turn. Further end‐group modifications of azide functional dendrimer precursor (N3P3‐(N3)6) and star polymer (N3P3‐(PCL‐N3)6) were achieved quantitatively via the Cu(I) catalyzed click reaction between azide functional groups and 1‐ethynyl pyrene in the final step. Moreover, the pyrene end‐capped phosphazene dendrimer and star polymer were used in noncovalent functionalization of multiwalled carbon nanotubes. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

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Well-defined AB 3 -type miktoarm star-shaped polymers with cholic acid (CA) core were fabricated with a combination of "click" chemistry and ring opening polymerization (ROP) methods. Firstly, azide end-functional poly(ethylene glycol) (mPEG), poly(methyl methacrylate) (PMMA), polystyrene (PS), and poly(e-caprolactone) (PCL) polymers were prepared via controlled polymerization and chemical modification methods. Then, CA moieties containing three OH groups were introduced to these polymers as the end groups via Cu(I)-catalyzed click reaction between azide end-functional groups of the polymers (mPEG-N 3 , PMMA-N 3 , PS-N 3 , and PCL-N 3 ) and ethynylfunctional CA under ambient conditions, yielding CA endfunctional polymers (mPEG-Cholic, PMMA-Cholic, PS-Cholic, and PCL-Cholic). Finally, the obtained CA end-capped polymers were employed as the macroinitiators in the ROP of e-caprolactone (e-CL) yielding AB 3 -type miktoarm star polymers (mPEG-Cholic-PCL 3 , PMMA-Cholic-PCL 3 , and PS-Cholic-PCL 3 ) and asymmetric star polymer [Cholic-(PCL) 4 ]. The chemical structures of the obtained intermediates and polymers were confirmed via Fourier transform infrared and 1 H nuclear magnetic resonance spectroscopic techniques. Thermal decomposition behaviors and phase transitions were studied in detail using thermogravimetric analysis and differential scanning calorimetry experiments.

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