A process comprising polymerizing in an aqueous medium at least one fluorinated olefin monomer other than vinylidene fluoride in the presence of a compound of formula (1): Rf(CH2CF2)m—(CH2)nSO3M  (1) wherein Rf is a C1 to C4 linear or branched perfluoroalkyl group, m is an integer of from 1 to 6, n is from 0 to 4, M is H, NH4, Li, Na or K, and a method of altering the surface behavior of a liquid comprising adding to the liquid the composition of a compound of formula (1).