Aromatic block copolymer ligand sensitized lanthanide nanostructures as ratiometric fluorescence probe for determination of residual K2CO3 in super engineering thermoplastics

[Display omitted] •An aromatic amphiphilic block copolymer named of D5S5 was synthesized.•D5S5 was self-assembled with Tb3+ and Rhodamine B to obtain nanoprobe of Tb-D5S5/RB.•Tb-D5S5/RB exhibits pH dependent fluorescence emission in acid and basic solution.•Tb-D5S5/RB shows ratiometric enhanced fluorescence as the increased K2CO3 content.•Tb-D5S5/RB nanoprobe is able to detect residual K2CO3 in super-engineering polymer. The residual catalyst (K2CO3) presented in the super engineering polyarylene ethers exerts side effects onto their processability and electrical properties. However, the sensitive and reliable analytical tools, that are able to detect residual K2CO3 content in these high performance thermoplastics, are rarely reported. Herein, we firstly synthesized an aromatic amphiphilic block copolymer bearing pendent carboxyl and sulfonate groups (named as D5S5). Next, a lanthanide ions mediated solvent-exchange self-assembly was explored to fabricate fluorescent metallopolymeric nanospheres composed of D5S5 and Tb3+ with strong green emission (named as Tb-D5S5). Then, the rhodamine B (RB) dyes were combined with the Tb-D5S5 to obtain the fluorescent probe of Tb-D5S5/RB, which exhibited a ratiometric fluorescence response to K2CO3. Specifically, the I545/I585 (intensity ratio of two emission bands at 545 nm and 585 nm) of probe linearly increased with the increasing K+ concentration of K2CO3 in the range from 0.05 to 7.41 mM. Furthermore, the sensing mechanism of this probe towards K2CO3 was revealed. Finally, the Tb-D5S5/RB probe was employed to determine the residual K2CO3 in a super engineering polyarylene ether produced by an industrial plant, which showed 85.98 %–89.31 % recoveries of the benchmark results obtained from the inductively coupled plasma optical emission spectrometer (ICP-OES).