SYNTHESIS OF TRIBLOCK COPOLYMERS MADE OF A FLUORINATED CENTRAL BLOCK AND 2 OUTSIDE POLY(1,3-DIOXOLANE) BLOCKS

Conditions are given that allow the preparation of highly amphiphilic triblock copolymers where the central block is a perfluoropolyether (n umber average molar mass equal to 2000) only soluble in freon-type sol vents, and the outside blocks are made of water soluble poly(1,3-dioxo lane) whose molar mass can be controled by the amount of 1,3-dioxolane consumed. Two methods are described: it is possible either to use CH2 Cl2 as a solvent (but only one of the two phases yields the expected p roduct) or to recourse to a Fomblin-rich fraction prepared previously as the initial diol (but the product of the reaction can be heterogene ous and separation has to be performed).