Controlled radical polymerization techniques such as RAFT allow fine control over polymer molecular weight and architecture. These techniques, however, do not eliminate compositional drifts in copolymerizations, which are the consequence of differences in monomer reactivity and can lead to compositionally non-uniform polymers that may hamper establishing structure-property relationships. One way to avoid compositional drifts is to use controlled monomer feeding techniques. Using the N-(2-hydroxypropyl)methacrylamide/N-acryloxysuccinimide (HMPA/NAS) comonomer pair for a first proof-of-concept, this manuscript reports an alternative approach to avoid compositional drifts and generate uniform copolymers by judicious selection of the initial monomer feed composition and controlling monomer conversion. Screening the copolymerization kinetics and copolymer composition of HPMA/NAS copolymers generated under various reaction conditions revealed that RAFT copolymerization of HPMA and NAS in DMF with an initial feed of 30 mol% NAS only resulted in a minimal compositional drift. While these reaction conditions are specific to the NAS/HPMA comonomer pair studied here, this approach may be applied to other comonomer pairs as well. The reactive NAS groups in a poly(HPMA-stat-NAS) copolymer obtained via this strategy could be post-modified with near-quantitative conversion with a amine-functionalized crown ether, which illustrates the versatility of this protocol to generate uniform reactive scaffolds for further post-polymerization modification. † Electronic supplementary information (ESI) available. See

A siloxane‐crown ether polyamide copolymer (PDMS‐PA‐DB18C6) was electrochemically investigated for fabrication of lead‐sensitive electrodes for trace analysis in aqueous solutions. The PDMS‐PA‐DB18C6 electrodes were successfully evaluated for anodic stripping voltammetric determination of lead(II) as a promising alternative for the detection of lead at ppb levels. By a judicious choice of the deposition time, electrolyte concentration and pulse amplitude, good analytical performance of the developed sensor could be achieved, with a linear response in the range of 20–700 ppb, when LOD of 3.5 ppb could be attained. This method showed a good degree of selectivity and sensitivity for lead, suitable for the determination of Pb2+ in wastewater sample.

N-(2-Hydroxypropyl)methacrylamide-co-N-acryloxysuccinimide with 2-aminomethyl-18-crown-6 (p(HPMA-NAS-18C6)) graft copolymer deposited on the gold (Au) electrode is able to bind heavy metal cations from aqueous solutions. The binding of the lead(II) cations (Pb 2þ ) is monitored by quartz crystal microbalance, cyclic voltammetry, and anodic stripping voltammetry. Electrochemical studies have demonstrated that the presence of p(HPMA-NAS-18C8) on the Au electrode surface resulted in the shift of Pb oxidation wave to less negative potentials, accompanied by the increase of the oxidation peak magnitude. The p(HPMA-NAS-18C6)-modified electrode could sensitively detect Pb 2þ cations in a range from 10 ppb to 4.39 ppm with a low detection limit of 0.17 ppb.

Correction for ‘Avoiding compositional drift during the RAFT copolymerization of N-(2-hydroxypropyl)methacrylamide and N-acryloxysuccinimide: towards uniform platforms for post-polymerization modification’ by John Moraes et al., Polym. Chem., 2015, 6, 3245–3251.