Poly( L ‐lactide) Nanoparticles via Ring‐Opening Polymerization in Non‐aqueous Emulsion

The preparation of poly( L ‐lactide) nanoparticles via ring‐opening polymerization (ROP) of L ‐lactide is conducted in non‐aqueous emulsion. In this process, acetonitrile is dispersed in either cyclohexane or n ‐hexane as the continuous phase and stabilized by a PI‐ b ‐PEO, respectively, a PI‐ b ‐PS copolymer as emulsifier. The air and moisture sensitive N ‐heterocyclic carbene 1,3‐bis(2,4,6‐trimethylphenyl)‐2‐ididazolidinylidene (SIMes) catalyzes the polymerization of L ‐lactide at ambient temperatures. Spherical poly( L ‐lactide) nanoparticles with an average diameter of 70 nm and a tunable molecular weight are generated. Hence, the non‐aqueous emulsion technique demonstrates its good applicability toward the generation of well‐defined poly( L ‐lactide) nanoparticles under very mild conditions.