 Fluorosurfactants, which have a polyfluorinated "tail" and a hydrophilic "head", serve as surfactants because they concentrate at the liquid-air interface due to their lipophobicity.Fluorosurfactants have low surface energies and dramatically lower surface tension.The fluorosurfactants perfluorooctanesulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) are two of the most studied because of their ubiquity, toxicity, and long residence times in humans and wildlife.