- In this work, a novel class of O2 /N2 switchable polymers is reported, which is prepared by atom transfer radical copolymerization (ATRcoP) of commercially available 2,2,2-trifluoroethyl methacrylate (FMA) and N,N-dimethylaminoethyl methacrylate (DMA). The copolymer is random and contains 10 FMA units and 85 DMA units. Its aqueous solution becomes transparent with O2 bubbling and turns to turbid with N2 purging. This O2 /N2 -responsive switchability between the transparent and turbid states is reversible. The FMA-DMA copolymer is thermosensitive and has a lower critical solution temperature (LCST) of 24.5 °C. O2 molecules interact with fluorinated groups of the copolymer and increase the LCST to 55 °C. Purging N2 removes O2 and returns the polymer thermosensitivity back to its initial state. The switchability occurs in the whole temperature range (24.5-55 °C).