Surface Chemistry of Fluoropolymer Barrier Films: Relation of Solution Variables to Film Properties.
NAVAL RESEARCH LAB WASHINGTON D C
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The quality of PFOMA barrier films, e.g., thickness, smoothness, surface texture, and resistance to lubricants, is shown to depend on the formulation variables of the PFOMA-solvent solutions from which they are cast. Thus, barrier film properties can be optimized by the choice of solvent composition and concentration. Scanning electron microscopy, optical microscopy, visual observation of drying films, and contact angle measurements all showed the relation of film properties to the solution variables. This was further established by calculating solubility parameters for the compositions studied, which showed that thermodynamically good solutions formed the best barrier films. Polymer phase partitioning probably occurred in a ternary solvent mixture resulting in unusually poor films. The relation of solution thermodynamics to the film properties was the basis for selection of an optimum solvent composition. From these techniques, an optimum concentration for casting was found to be one yielding a film thickness of about 0.5 micrometers. Author
- Physical Chemistry
- Lubricants and Hydraulic Fluids