Controlled Polymerization Catalysis for the Synthesis of Degradable Amphiphilic Polycarbonates from CO₂

Synthetic water-soluble polymers are ubiquitous in solution-based applications, but their petroleum origin and nondegradable bonds create environmental concerns. Here, CO₂- and glycerol-derived polycarbonates incorporating hydrophilic diglycerol motifs are prepared as a general-purpose water-soluble degradable polymer platform. A high-performance heterodinuclear [Co(III)/K(I)] catalyst enables controlled ring-opening copolymerization (ROCOP) of CO₂ with an acetal-protected epoxide, delivering well-defined polycarbonates with low dispersity (D̵ < 1.2) and predictable molecular weights (≈2000-20,000 g mol^-1). The catalysis is tolerant to protic initiators (chain transfer agents, CTAs), enabling control over both chain length and end-group chemistry. Deprotection of the acetals is quantitative and affords water-soluble polycarbonates incorporating hydrophilic diglycerol motifs. Using natural hydrophobic initiators yields amphiphilic polymers that self-assemble in water to form nanostructures of ≈7-11 nm with a critical micelle concentration of ≈30 mg L^-1. These polymers are stable at either neutral or acidic pH but depolymerize in alkaline solution to form nontoxic small molecules. Degradation proceeds by hydroxyl chain-end-initiated backbiting, i.e. by self-immolation, with pH- and end-cap-dependent kinetics, with complete degradation occurring over minutes to one month. Overall, this renewable polycarbonate chemistry, which is ∼23 wt % CO₂-derived; ∼77 wt % glycerol-derived, combines precise polymerization catalysis, spontaneous aqueous self-assembly and controllable aqueous degradability which are important for next-generation surfactants.