CO2-Based Non-ionic Surfactants: Solvent-Free Synthesis of Poly(ethylene glycol)-block-Poly(propylene carbonate) Block Copolymers

Copolymerization of carbon dioxide (CO2) and propylene oxide (PO) is employed to generate amphiphilic polycarbonate block copolymers with a hydrophilic poly(ethylene glycol) (PEG) block and a nonpolar poly(propylene carbonate) (PPC) block. A series of poly(propylene carbonate) (PPC) di- and triblock copolymers, PPC-b-PEG and PPC-b-PEG-b-PPC, respectively, with narrow molecular weight distributions (PDIs in the range of 1.05-1.12) and tailored molecular weights (1500-4500 g mol(-1)) is synthesized via an alternating CO2/propylene oxide copolymerization, using PEG or mPEG as an initiator. Critical micelle concentrations (CMCs) are determined, ranging from 3 to 30 mg L-1. Non-ionic poly(propylene carbonate)-based surfactants represent an alternative to established surfactants based on polyether structures.