Abstract fluorocarbon-modified poly(N_isopropylacrylamide) has been synthesizedby copolymerization of N-isopropyl acrylamide with a small amount of acrylateor methacrylate containing a perfluoroalkyl group It was found that the hydrophilicity of macromolecular backbone is an important factor to the solution properties of the copolymers and that hydrophobic association between fluorocarbon groups is strongerthan that between the corresponding hydrocarbon analogies