PCL(4k)-PEG(6k)-PCL(4k) is a triblock ABA amphiphilic polymer which can form micelles upon dispersion in an aqueous media. The polymer is biodegradable via hydrolysis on the ester linkages. The OH end groups allow further derivatization. This class of polymer enables new avenues for drug delivery, gene therapy, and tissue engineering. Reagent grade, for research purpose.