A composition comprising one or more compounds of formula (I) or (II): ##STR00001## wherein: R.sub.f is a linear or branched perfluoroalkyl having 1 to 7 carbon atoms, optionally interrupted by one to three oxygen atoms, r and q are each independently an integer of 1 to 3, j is 0 or 1, or a mixture thereof, x is from about 1 to about 2, Z is --O--, --S--, or --NR--, R is hydrogen or an alkyl group containing 1 to 4 carbon atoms X is hydrogen or M, and M is an ammonium ion, an alkali metal ion, or an alkanolammonium ion, and its use in providing surface properties to substrates is disclosed.