(274a) Effect of Perfluorocarbon Vapor Concentration On Surface Tension of Water

Effect of perfluorocarbon
vapor concentration on surface tension of water

Vasiliy
Chernyshev and Mikhail Skliar

Chemical
Engineering

University of
Utah

Perfluoropentane (PFP) and other perfluorocarbons (PFCs) are
highly hydrophobic, biocompatible compounds that have found a variety of medical
applications. For example, stabilized perfluorocarbon
are used as contrast agents during ultrasound imaging and in targeting drug
delivery. Other applications include their use and aerosol propellants, lung
ventilation, and anesthesia.  Despite
significant interest in these compounds, the study of their interfacial properties
has received limited attention. Following our previous work, we investigated
the influence of PFP vapor on the surface tension of a water droplet at room
temperature. The droplet surface tension, volume and surface area measurements
were carried out by means of real-time pendent-drop tensiometer developed us.
The study followed an experimental procedure summarized in Fig. 1 and indicated
substantial decrease of surface tension of water with time (Fig. 2) as a result
of PFP vaporization. It was found that the tension decreases linearly with the increase
of the PFP concentration in the gas phase, as shown in Figure 3. The effect of perfluorohexane
vapor on surface water tension was also investigated and directionally similar
but smaller influence was found.

Figure 1: The experimental procedure.

Figure 2: Surface tension of water changes with PFP and PFH evaporation. At time zero, a drop of liquid
water was formed inside cuvette. After allowing 10 min for thermal and vapor-liquid
water equilibration, liquid perfluorocarbon was injected. Each data point is
the average of 8 runs.

Figure 3: Correlation between water surface tension and PFP vapor concentration.