Towards nanoparticles with site-specific degradability by ring-opening copolymerization induced self-assembly in organic medium

• Published in: Polymer chemistry Vol. 12; no. 4; pp. 594 - 67
• Main Authors: Zhu, Chen, Nicolas, Julien
• Format: Journal Article
• Language: English
• Published: Cambridge Royal Society of Chemistry 02.02.2021; Royal Society of Chemistry - RSC
• Subjects: Block copolymers; Chain transfer; Chains; Chemical Sciences; Chemical synthesis; Copolymerization; Degradation; Heptanes; Methylene; Nanoparticles; Nanospheres; Polycaprolactone; Polymer chemistry; Polymers; Ring opening polymerization; Self-assembly
• ISSN: 1759-9954; 1759-9962
• DOI: 10.1039/d0py01425g

Reversible addition-fragmentation chain transfer (RAFT)-mediated radical ring-opening copolymerization-induced self-assembly (rROPISA) in heptane at 15 wt% solids was successfully applied to the copolymerization of benzyl methacrylate (BzMA) with 2-methylene-1,3-dioxepane (MDO) from a poly(lauryl methacrylate) (PLMA) macro-RAFT agent. Despite less efficient control of the copolymerization compared to similar copolymerizations with 2-methylene-4-phenyl-1,3-dioxolane (MPDL) or 5,6-benzo-2-methylene-1,3-dioxepane (BMDO), it yielded stable, diblock copolymer nanospheres ( D z = 100-200 nm) containing tunable amounts of polycaprolactone (PCL)-like degradable units in the core ( F MDO = 0.04-0.19), resulting in significant degradation under accelerated hydrolytic conditions. Synthesis of surface-degradable diblock copolymer nanoparticles was then performed through the synthesis of P(LMA- co -BMDO) and P(LMA- co -MPDL) macro-chain transfer agents (CTAs). Even though partial livingness during chain extension with BzMA by PISA was noticed, stable nanospheres were obtained for F BMDO = 0.05 and porous nanospheres for F BMDO = 0.08-0.09, whose average diameters increased with the BMDO content. Attempts to prepare " all-degradable " vinyl particles were also made by rROPISA of BzMA and BMDO (or MPDL) from degradable macro-CTAs showing degradation in agreement with the copolymers' expected structure. Radical ring-opening copolymerization-induced self-assembly (rROPISA) was successfully applied to the synthesis of core-, surface- or surface plus core-degradable nanoparticles in heptane, leading to site-specific degradability by rROPISA.