A novel reversible colorimetric chemosensor for rapid naked-eye detection of Cu2+ in pure aqueous solution

A novel water-soluble polymer P(NIPAM-co-RhBBA) containing pendant rhodamine B-based dyes is successfully synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization. P(NIPAM-co-RhBBA) in pure aqueous solution exhibits highly sensitive and selective detection of Cu2+ ions accompanied with a remarkable color change from colorless to purple within 20 s, which can be monitored directly by naked eyes. The on-off-on color switching behavior upon adding Cu2+ and EDTA ions alternately to P(NIPAM-co-RhBBA) aqueous solution for several successive cycles demonstrates a superior reversible colorimetric chemosensor for further applications. Furthermore, the low-cost test strips are fabricated using P(NIPAM-co-RhBBA) for convenient and efficient detection of practical Cu2+ ions in real water samples.