Preparation of oligomers and co-oligomers of highly fluorinated sulfinic acids and salts thereof

A method for preparing an oligomer comprising:

• (a) providing a highly fluorinated vinyl sulfonyl halide;
• (b) oligomerizing the highly fluorinated vinyl sulfonyl halide with an initiator to provide a highly fluorinated oligomeric sulfonyl halide according to the following formula (I):
• (c) and, reducing the highly fluorinated oligomeric sulfonyl halide to a highly fluorinated sulfinate oligomer according to the following formula (IV),
• wherein X1, X2, and X3 are independently selected from F, Cl and CF3;
• R is independently selected from H, I, Br, linear or branched alkyl, and linear or branched fluoroalkyl group optionally a heteroatom;
• R1 is a linear or branched perfluorinated linking group, which may be saturated or unsaturated, substituted or unsubstituted, and optionally comprises a heteroatom;
• Y is a halide;
• M is a cation;
• and m is at least 2.