Structural and thermosensitive properties of cyclotriphosphazenes with poly(ethylene glycol) and amino acid esters as side groups

Abstract

Structural and thermosensitive properties of cyclotriphosphazenes with poly(ethylene glycol) and Amino Acid esters as side groups were studied. The nucleophilic subsitution of hexachlorocylotriphosphazene with alkoxy polyethylene glycol (APEG) gave predominantly the cis-nongeminal isomer at low reaction temperature. A large amount of cis- and trans-isomers were also produced. Hetrogenously substituted thermosensitive trimers were synthesized by stereocontrolled partial substitution of N 3P 3Cl 6 with low molecular APEG followed by the aminolysis of the remained chloride functions with AAE. The phase transition rate of the thermosensitive trimers was found to be very fast and responsive even in dilute concentrations.