Mild synthesis of amino-poly (ethylene glycol)s. Application to steric stabilization of clays

The hydroxyl end groups of poly(ethylene glycol) (PEG) have been transformed easily and quantitatively into amino groups via the Mitsunobu reaction Phthalimide was alkylated with PEGs and the hydrazinolysis of the resulting phthalimido-PEGs gave the amino compounds in high yields. Quaternization of the amino groups leads to hydrophilic polymer chains bearing a positive charge on one or two ends, depending on the chosen PEG. Such products can be used to protect sterically, negatively charged particles such as clays.