Other suitable nonionic fluorinated hydrocarbon surfactants are those where the fluorinated hydrocarbon portion exhibits a branched chain structure and which have an aliphatic per-fluorocarbon group at one end of the chain, such as those having the formula: Rf (OCH2 CH2)m OR where R is a lower alkyl, suitably CH3, m is from 2 to 20 and Rf is C8 F15, C10 F19, or C12 F19.