Pyrene substituted amphiphilic ROMP polymers as nano-sized fluorescence sensors for detection of TNT in water

Abstract

In this study, pyrene substituted amphiphilic ring-opening metathesis polymers (ROMP) were developed as fluorescence probes for the trace detection of trinitrotoluene (TNT) in water. Pyrene substituted hydrogenated amphiphilic ROMP polymers were synthesized using an efficient combination of ROMP/cross-metathesis (CM), transesterification and hydrogenation reactions. Dimethyl-5-norbornene-2,3-dicarboxylate (M1) monomer was polymerized via ROMP/CM reactions in the presence of allyl polyethylene glycol methyl ether as the chain transfer agent. The resulting diblock amphiphilic ROMP polymer (P1) was functionalized with 1-pyrenemethanol in a one-pot procedure using sequential transesterification and hydrogenation reactions. The pyrene substituted modified polymer (P2) formed sphere-like micelle structures with an average particle size of 30.17 (±5.65) nm in water as determined by transmission electron microscopy analysis. The fluorescence quenching response of the P2 sensor against TNT and other nitro aromatic compounds in water media was examined in details. The monomer emission of P2 was found to be highly sensitive to TNT concentration and the Stern-Volmer constant of the P2 sensor was measured to be 1.5 × 105 M−1 under optimized conditions with a limit of detection of 64 nM.