PCL(3k)-mPEG(2k) is an amphiphilic block copolymer which can self-assemble in water to form micelles. The arrangment of the micelles is polycaprolactone (PCL) being shielded from water by the hydrophilic PEG chain. Thus, it can be used to encapsulate hydrophobic drugs which can improve concentration and long blood circulation. Reagent grade, for research purpose.