PCL(4k)-PEG(3k)-Thiol consists of two different polymers, a hydrophobic polycaprolactone (PCL) block and a hydrophilic PEG block. The polymer can form micelles in water with PCL core and PEG shell formation. The core can be used to entrap hydrophobic drugs for controlled release drug delivery. The thiol moiety is reactive with maleimide via thioether bond formation. Reagent grade, for research purpose.