In this work, a novel class of O-2/N-2 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 O-2 bubbling and turns to turbid with N-2 purging. This O-2/N-2-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 degrees C. O-2 molecules interact with fluorinated groups of the copolymer and increase the LCST to 55 degrees C. Purging N-2 removes O-2 and returns the polymer thermosensitivity back to its initial state. The switchability occurs in the whole temperature range (24.5-55 degrees C).