Zonyl® Fluorinated nonionic surfactants

The surface tension of Zonyl fluorinated surfactants, featuring the hydrophobe F(CF2CF2)3-gCH2CH2—, in acids and alkali is shown in Table 4.8. Anionic, cationic, nonionic, or amphoteric surfactants listed in Table 4.8 can lower the surface tension of 10% potassium hydroxide, 25% sulfuric acid, 37% hy-... 

The adsorption of fluorinated surfactants on coal was investigated by Lai and Gray [52] by measuring the contact angles, the spreading coefficient, and the effect of the fluorinated surfactant on flotation. The fluorinated surfactants used were Zonyl FSN (nonionic), Zonyl FSC (cationic), Zonyl FSK (amphoteric), and Zonyl FSA (anionic). The contact angle of water on coal is about 38°-42°. The anionic fluorinated surfactant increased the contact angle to 80°-90°. The other fluorinated surfactants were less effective. The adsorption of the fluorinated surfac-... 

The adsorption of fluorinated surfactants at the electrode-solution boundary is of considerable practical interest for the application in electrochemical systems [60-64) (see Chapter 8). The electrochemical behavior of Zonyl FSN (nonionic), Zonyl FSD (cationic), Zonyl FSA (anionic), Fluorad FC-99 (anionic), and Fluorad FC-135 (cationic) at Hg and Pt electrodes has been investigated by using cyclic voltammetry and interfacial differential capacitance measurements. When the electrode is relatively hydrophobic, such as Hg, and the surface charge density is relatively low, the fluorinated surfactants, as well as hydrocarbon surfactants, are adsorbed with their hydrophobic segments oriented toward the electrode. The interaction of fluorinated surfactants with the Hg electrode is weaker and the adsorbed layer is less compact than those of hydrocarbon surfactants. When the electrode is more hydrophilic, such as Pt, or the surface charge density is high, the surfactants adsorb with their hydrophilic end group toward the electrode surface. 

A mixture of Zonyl FSN, a nonionic fluorinated surfactant, and Tergitol NP-10, a nonionic hydrocarbon-type surfactant (nonylphenol with 10 oxyethylene units Union Carbide Corp.), exhibited surface tension synergism (Fig. 4.29). The dynamic surface tension of the 1 1 mixture is lower than the dynamic surface tension of the individual components. 

The foaming properties of fluorinated surfactants vary widely (see Section 4.9). For example, amphoteric surfactants, Zonyl FSK and Zonyl FSC, are outstanding foaming agents. In contrast, the anionic fluorinated surfactant, Zonyl FSP, and the nonionic fluorinated surfactant, Zonyl FSN, are low foaming. In some systems, Zonyl FSP can function as an antifoam agent. 

Fluorinated surfactants are available as liquids, pastes, or solids. Some are diluted with water or an organic solvent some are sold in the 100% active ingredient form. If the system cannot tolerate water, an undiluted fluorinated surfactant or a surfactant formulated as an organic solution has to be used. Some nonionic fluorinated surfactants, (e.g., Fluorad FC-430, Zonyl FSN-100, and Zonyl FSO-100) are soluble in several nonaqueous solvents. Generally, the surfactant must be soluble to be effective. Hence, solubility of the surfactant may limit its use in some systems. 

Fluorinated surfactants usually differ widely in their foaming power (see Section 4.9). Cationic fluorinated surfactants and amphoteric fluorinated surfactants (e.g., Zonyl FSK) are foaming agents in aqueous media. On the other hand, nonionics (e.g., Zonyl FSN and Zonyl FSO) are low-foaming surfactants [1]. Endcapping reduces foaming. 

Anionic, cationic, and nonionic fluorinated surfactants are used in various metal treatment processes. Metal surfaces are treated to prevent corrosion, reduce mechanical wear, or enhance the aesthetic appearance. Fluorinated surfactants are used in the phosphating process for aluminum and in bright dips for copper and brass. Some fluorinated surfactants (e.g., the anionic surfactants Zonyl FSA and Zonyl FSP) are strongly adsorbed on metals and provide water and solvent repel-lency [1]. 

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