PCL(5k)-mPEG(5k) has a hydrophobic polycaprolactone (PCL) block chemically tethered to a hydrophilic PEG block. Upon dispersion in water, the polymer self assembles to form micelles with PCL core and PEG shell. In drug delivery application, the core regions serves as reservoirs for hydrophobic drugs while the shell regions provide protection against protein adsorption which can lead to degradation (via enzymatic or hydrolysis). Reagent grade, for research purpose.