Thermoresponsive Modular Nano-Objects Via RAFT Dispersion Polymerization in a Non-Polar Solvent

Thermoresponsive polymer nano-objects able to dynam-ically change their morphology in response to modifications in the local temperature are finding growing attention for biomedical, optical, and oil & gas applications. This smart behavior can be accessed by precisely controlling the microstructure of AB block copolymers, which can be obtained by leveraging the pseudoliving character of the reversible addition-fragmentation chain transfer (RAFT) polymerization. Most of the examples reporting the synthesis of highly controlled thermores-ponsive nano-objects via RAFT dispersion polymerization currently refer to aqueous systems. However, the possibi l i t y of synthesizing thermor-esponsive copolymers with a well-defined phase separation and bul k response in organic solvents is becoming more and more critical for applications in the oil & gas field and in lubricants for heat engines. In this study, we propose a convenient strategy for synthesizing mod u l a r thermoresponsive block copolymers dynamically self-assembling into nano-objects with different morphologies in the hydrocarbon blend dectol (50:50% v/v decane/toluene). Two macromolecular chain transfer agents (macroCTAs) with different degree of polymerization were synthesized from lauryl methacrylate. The chain extension of these macroCTAs with di(ethylene glycol) methyl ether methacrylate via RAFT dispersion polymerization led to copolymers forming , when the temperature is lowered below their cloud point, nano-objects whose morphology could be controlled by modulating the solid content of the formulation and the length of both blocks in the copolymer. We also revealed how the phase-separation temperature and bul k response is influenced by these same parameters, allowing us to tune the material response to the needs of the final application.