Method for manufacturing fluoropolymers

A process for manufacturing a (per)fluoropolymer, said process comprising polymerizing one or more fluorinated monomers in the presence of a multi-phase medium, said medium comprising:

• (A) a water phase (W);
• (B) at least one fluorinated surfactant (FS) having formula (I) here below:
• Rf—(OCF2CF2)k-1—O—CF2—COOXa (I)
• wherein Rf is a C1-C3 perfluoroalkyl group comprising, optionally, one or more ether oxygen atoms, k is 2 or 3 and Xa is selected from the group consisting of a monovalent metal and an ammonium group of formula NRN4, wherein RN, equal or different at each occurrence, is a hydrogen atom or a C1-C3 alkyl group;
• (C) an oil phase (O) comprising:
• at least one non-functional (per)fluoropolyether (non-functional PFPE) comprising at least one (per)fluoropolyoxyalkylene chain (RF) and free from functional end-groups, and
• at least one functional (per)fluoropolyether (functional PFPE) comprising at least one (per)fluoropolyoxyalkylene chain (R′F)] and having a number average molecular weight of at least 1000 and a solubility of less than 1% by weight in water at 25° C.;
• wherein the at least one non-functional (per)fluoropolyether is present in an amount ranging from 0.01% to less than 30% by weight of the total weight of the multi-phase medium.