Synthesis of lipid-b-poly(2-isopropyl-2-oxazoline) and successive study of pH- and thermo-sensitive mixed micelles by combination with lipid-b-poly(acrylic acid)

This paper reports the synthesis of a thermo-sensitive amphiphilic copolymer from linseed oil and its successive engagement in micelles formation. A CROP lipoinitiator was first synthesized in two steps and engaged in the polymerization of 2-isopropyl-2-oxazoline. The physico-chemical behavior of the final lipid-b-poly(2-isopropyl-2-oxazoline) copolymer was studied. This copolymer presents a cloud point temperature of 32 °C at pH = 4.6 (in the presence of 0.1 mol L⁻¹ NaCl) and self-organizes into well-defined micelles (10 nm) with a critical micellar concentration of 10 mg L⁻¹. The combination of this copolymer with a pH-sensitive lipid-b-poly(acrylic acid) then allowed the preparation of mixed micelles, leading to a system sensitive to both pH and temperature modifications.