Understanding Fluorescence Quenching in Polymers Obtained by RAFT

Abstract

Reversible addition−fragmentation chain transfer (RAFT) polymerization is a versatile process to obtain polymers with controlled architecture and molecular weight from a large variety of monomers. This appears to be a very attractive method for the synthesis of fluorescent polymers for different applications. However, fluorescent polymers obtained by RAFT are known to suffer strong fluorescence quenching. Here, we report the quenching of coumarin 343 (C343) fluorescence by four different chain transfer agents (CTA) used in RAFT polymerization: carboxymethyl dithiobenzoate (CMDB), tert-butyl dithiobenzoate (tBDB), menthonyl dithiobenzoate (MDB), and bis(3-methylbutyl)-2-(thiobenzoylthio)succinate (MBTS). The quenching ability of these CTAs was compared with that of a macroCTA (poly(DcA)−MBTS) obtained from the RAFT polymerization of N-decylacrylamide (DcA) using MBTS as chain transfer agent. The results of stationary and time-resolved fluorescence measurements of C343 with the different CTA and macroCTA c...