Tuning the Thermo-Sensitivity of Micellar Systems through a Blending Approach

This paper reports an original and easy route toward thermosensitive micelles based on a lipidic core and with adjustable cloud point temperatures (TCP) through a simple blending approach between two copolymers of different TCP. The cationic ring-opening polymerization (CROP) of various 2-alkyl-2-oxazoline monomers was first investigated from both mesylated and tosylated lipoinitiators and different lipid-b-poly(2-methyl-2-oxazoline), lipid-b-poly(2-ethyl-2-oxazoline), lipid-b-poly(2-isopropyl-2-oxazoline) and lipid-b-poly((2-ethyl-2-oxazoline)-co-(2-isopropyl-2-oxazoline)) copolymers were synthesized. Blending of lipid-b-p(EtOx) and lipid-b-p(iPrOx) copolymers in various proportions were then prepared and their TCP investigated through UV–visible spectroscopy. Very interesting results were obtained as the blends exhibit a single TCP ranging from 35 to 45 °C. Furthermore, the blends TCP correspond to those of the statistical lipid-b-p((EtOx)-co-(iPrOx)) for the same p(EtOx)/p(iPrOx) content up to 52 wt % ...