Poly- and perfluoroalkyl substances (PFASs) have been used in various industrial applications and consumer products, but have received increasing global concern due to their persistence, bioaccumulation and adverse effects on living organisms. Some of these compounds are now banned and more are expected to follow. There is, however, a lack of fundamental understanding of their interactions with cell membranes or the dangerous concentration limits. We have studied the interaction of three groups of perfluoroalkyl substances (i.e. carboxylic, sulfonic and sulfonamide acids) with a phospholipid bilayer, DMPC. The results showed that they interact strongly with the lipids and are incorporated into the bilayers, displacing the lipids. The new experiment aims to explore how polyfluorinated substances, which are used as alternatives to perfluoroalkyl substances, interact with DMPC.