Synthesis, characterization, and Pb2+ ion sensing application of hexa‐armed dansyl end‐capped poly(ε‐caprolactone) star polymer with phosphazene core

Abstract

ABSTRACTNovel hexa‐armed dansyl end‐capped poly(ε‐caprolactone) (PCL) star polymer with phosphazene core (P2) was prepared via ring opening polymerization (ROP) and esterification reactions. P2 showed dual fluorescence emission when excited at 328 nm in acetonitrile : water (6 : 4) due to twisted intramolecular charge transfer (TICT) between dimethylamino and naphthalene units in the dansyl moiety. TICT emission band (A band) in the emission spectra red‐shifted with increasing solvent polarity. P2 responded to the addition of Pb2+, Hg2+, Co2+, Cd2+, Mn2+, and Zn2+ metal ions by decreasing TICT emission band with slight bathochromic shifts. The highest quenching efficiency was observed for Pb2+ ion with Stern–Volmer constant of 324.74M−1. The Stern–Volmer plot for Pb2+ was rather linear with the increasing concentration of the quencher, indicating a dynamic (collisional) quenching mechanism. Stern–Volmer constants for Hg2+, Co2+, Cd2+, Mn2+, and Zn2+ ions were found to be 212.33, 189.21, 36.24, 20.84, and 20.69, respectively. Besides, the highest quenching efficiency (94.24%) was attained in the presence of Pb2+, suggesting that P2 could be employed as a potential Pb2+ chemical probe. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42380.