PCL(5k)-PEG(8k)-PCL(5k) is a triblock amphipathic polymer which can form micelles upon dispersion in an aqueous media. The polymer is biodegradable via hydrolytic attack on the ester linkages. The OH terminals can be further derivatized. This class of polymer enables new avenues for drug delivery, gene therapy, and tissue engineering. Reagent grade, for research purpose.