Polymers derived from fluoroketones. II. Wetting properties of fluoroalkyl acrylates and methacrylates

Abstract

Abstract The critical surface tension of wetting (γ c ) for certain branched‐chain polymeric fluoroalkyl acrylates and methacrylates was obtained. Polymeric materials utilized in this study can be represented by the repeating units , where R is H or CH 3 , R′ is H or F, and X is F or Cl, by \documentclass{article}\pagestyle{empty}\begin{document}$ \rlap{--} [{\rm CH}_2\hbox{---}{\rm CH}({\rm COO}({\rm CH}_2)_n {\rm OCF -}({\rm CF}_3)_2)\rlap{--}] $\end{document} , where n is 2, 5, or 11, and by \documentclass{article}\pagestyle{empty}\begin{document}$ \rlap{--} [{\rm CH}_2 \hbox{---}{\rm C}({\rm R})({\rm COOCH}_2 ({\rm CF}_2)n'{\rm CF}_3)\rlap{--}] $\end{document} , where R is H or CH 3 and n ′ is 2 or 6. Monomer synthesis involved either the direct acylation of a fluoroketone–metal fluoride adduct or a fluoroalcohol with acryloyl or methacryloyl chloride or a displacement reaction between a fluoroketone–metal fluoride adduct and an ω‐bromoester. In general, modifications in the pendent fluoroalkyl group affected γ c in a manner predictable from previous work by Zisman et al.; e.g., γ c was increased when either H or Cl was substituted for F in the side chain. In polymeric alkyl acrylates containing a heptafluoroisopropyl side chain γ c increased as the fluorocarbon group was removed from the proximity of the polymer backbone by intervening methylene groups. A comparison of the wetting properties of polyacrylates containing either a perfluoroisopropyl or n ‐perfluoropropyl group showed that the polymer containing the isopropyl group had a lower γ c .