Fluorine‐containing hydrophobically associating polymers have been synthesized by copolymerization of acrylamide with a small amount of an acrylate or methacrylate having a fluorocarbon containing ester group. It was found that hydrophobic associations occurring between these fluorocarbon chains was stronger than the interactions of the corresponding hydrocarbon comonomers and depend on the length of the fluorocarbon chain. The rheological properties of the copolymer solutions were studied. The solutions were found to be highly pseudoplastic but the viscosity loss was completely reversible upon removal of shear. Evidence for hydrophobic association of the fluorocarbon groups was obtained by the dependence of the Brookfield viscosity on temperature, the addition of NaCl, and the addition of organic solvents, urea, and surfactants.

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The synthesis of polyacrylamide copolymers containing fluorine-containing acrylates 1, 2, 4 or 5 or silicone-containing methacrylate 6 was carried out by emulsion polymerization using persulfate as initiators and ionic perfluoro surfactants. The Brookfield viscosities of these copolymers, especially those containing 1 or 2, were much higher than the laurylacrylate (3) containing co polymer. The comonomer content of the 1 or 2 containing copoly mers that were most strongly viscosifying was only .07-.28 mole percent, well below that of the corresponding copolymers contain ing 3. Viscosity increases of the 1 and 2 copolymers, observed upon increases in temperature or NaCl concentration were consis tent with association of these copolymers through intermolecular hydrophobic binding. Reduced viscosity or dynamic light scattering studies are consistent with the existence of polymer assemblies above polymer concentrations of about 100 pm. Addition of surfac tants water miscible organic solvents or increasing shear rate was shown to lead to sharp viscosity decreases consistent with the proposed model.The replacement of hydrocarbon-by perfluoroalkyl groups in hydrophobically associating polymers 1 is of potential interest since the hydrophobic character of perfluoroalkyl groups is more pronounced compared to their hydrocarbon analogs. 2 Thus, the critical micelle concentrations of fluorocarbon surfactants generally are significantly lower than the hydrocarbon analogs of the same chain length and surface tensions of fluorocarbon surfactant solutions are also much lower. 2 -3 Also hydrophobic bonding of fluorocarbon surfactants to β-cyclodextrines is much stronger (about 300 times) compared to similar hydrocarbon containing surfactants. 4 Significantly, the latter process is enthalpy driven (ΔΗ = -9.0 kcal/mole, AS = -12 eu) whereas the bonding of the fluorocarbon

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