Perfluorocarbons surface tension

The surface of PTFE articles is sHppery and smooth. Liquids with surface tensions below 18 mN/m(=dyn/cm) are spread completely on the PTFE surface hence, solutions of various perfluorocarbon acids in water wet the polymer (78). Treatment with alkafl metals promotes the adhesion between PTFE and other substances (79) but increases the coefficient of friction (80). 

Chemicals Company Ltd., Tokyo. 6ED was highly pure as confirmed by gas-liquid chromatography(GLC), thin layer chromatography(TLC) and surface tension measurements. Sodium dodecyl sulfate, C 2H25S02Na (SDS) was purified by recrystallization from ethanol twice. p-[(CF3)2CF]2C=C(CF )0(CH2CH20)2CH3(NF) was donated by Neos Co. 8-Anilino-l-naphthaiene sulfonic acid ammonium salt(ANS) was obtained from Wako Pure Chemical Industries, Ltd. Perfluorocarbon oil(pp-l,... 

The surface of PTFE material is smooth and slippery. It is considered to be very low energy surface with yc = 18.5 dyne/cm (mN/m)33 and can be, therefore, completely wetted by liquids with surface tensions below 18 mN/m, for example, solutions of perfluorocarbon acids in water.34 The PTFE surface can be treated by alkali metals to improve this wettability and consequently the adhesion to other substrates,35 but this increases its coefficient of friction.36... 

Although the high surface tension of perfluorocarbons allows closure of retinal breaks and prevents them from flowing into the subretinal space, particularly during intraocular manipulation, they can gain entry into the subretinal space, resulting in residues in the eye (15,16). The removal of perfluorocarbons is recommended at the end of surgery, but they can be left in the eye for limited periods of time (17). 

Thus, the use of gases that possess very low surface tension (e.g., perfluorocarbons) should reduce the pressure against bubble collapse such that the radius of the microbubbles formed would be small. Indeed, perfluorcarbon microbubbles prepared from perfluoropropane or perfluorobutane form bubble diameters on the order of 1 to 2 pm, which are ideal for passing through capillary beds. In addition, because of their extremely low solubility in aqueous media, the perfluorocarbon microbubbles would not dissolve in the venous blood and are therefore less prone to collapse. 

When a hydrophilic functional group is attached to a perfluorocarbon chain the resulting fluorosurfactants (e. g. n-C F2 +iCOOLi, with n > 6) can reduce the surface tension of water from 72 dyn cm to 15-20 dyn cm compared to 25-35 dyn cm for analogous hydrocarbon surfactants [11],... 

Three decades have passed since the high solubility of gases in perfluorocarbons was reported with the striking demonstration of a mouse breathing while immersed in perfluorocarbons. Perfluorodecalin (Figure 3.1), which has a low surface tension... 

Table 8.4. Surface tension values of alkanes and perfluorocarbon fluids (25°C)...

In fact, perfluorocarbons as a class of materials exhibit the lowest possible surface tension, y, of all organic liquids and they spread spontaneously over nearly all solid surfaces. 

The density of the perfluorocarbons is usually more than twice that of their hydrocarbon counterparts. The low dielectric constants, surface/interface tensions and refractive indices of perfluorocarbons reflect their nonpolar character as liquids and solvents.6... 

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