PCL(2k)-PEG(1k)-MAL is a maleimide functionalized amphipathic polymer which can react with thiol molecule at pH 6.5-7.5 to form a stable thioether linkage. The polymer can self-assemble in water to form micelles where the core regions (polycaprolactone (PCL)) can be used to entrap/congregate hydrophobic drugs. Reagent grade, for research purpose.