Development of redox-active polycaprolactone and its electrochemical redox behavior in aqueous media†

Redox-active polymers have garnered significant attention for their potential in organic radical batteries (ORB) due to their unique redox capabilities. However, traditional redox-active polymers often consist of non-degradable aliphatic chains, raising environmental concerns. To address this issue, we developed a polycaprolactone-based organic radical polymer, , which leverages the biodegradable and non-toxic properties of polycaprolactone (PCL). was synthesized by incorporating 2,2,6,6-tetramethylpiperidin-1-yl oxyl (TEMPO) as a redox-active pendant group. We further investigated its redox properties in aqueous solutions. While exhibited redox activity, its performance as a rechargeable battery material was limited, likely due to the degradation of TEMPO during cycling. Nonetheless, cytotoxicity tests demonstrated that both and its degradation products were non-cytotoxic, highlighting its potential as an environmentally friendly material for future applications.