PCL(4k)-PEG(1k)-VS is a block copolymer with both hydrophobic polycaprolactone (PCL) and hydrophilic PEG segments. It is a self-assembling polymer which can be used to entrap hydrophobic drugs while maintaining long blood circulation in vivo. The vinyl moiety can react with thiol molecule in the presence of radical initiator via thiol-ene reaction. Reagent grade, for research purpose.