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Том 487, № 1 (2019)
- Год: 2019
- Статей: 2
- URL: https://journals.rcsi.science/0012-5016/issue/view/9266
Physical Chemistry
Strong Dependence of Contact Angle on Pressure
Аннотация
Despite the fact that ordinary pressures typically slightly affect the properties of condensed phases and their surface layers, quite a pressure-sensitive quantity was found in the physical chemistry of surfaces. This is contact angle. In experiments with an air bubble stuck to a solid surface in water, a less than double increase in the hydrostatic pressure led to a more than 10° increase in the contact angle, provided that the contact angle was sufficiently less than 90°. During these changes, the three-phase contact line remained immobile, and the process reduced only to a change in the orientation of the liquid–gas interface. If the angle (be it acute or obtuse) was close to 90°, the three-phase contact line became mobile as an alternative way to reach equilibrium. To explain these phenomena, a thermodynamic theory was formulated. It was shown that, if the three-phase contact line is immobile, an increase in the pressure in the liquid always causes an increase in the contact angle.
87-90
Inhibition of Redox Reactions in a Low-Frequency Field
Аннотация
The effect of low-frequency impacts on a system consisting of two biochemically active components, methylene blue dye and ascorbic acid, was investigated. Each of these components can be both reversibly oxidized and reversibly reduced. It was found that low-frequency oscillations do not accelerate the redox processes in this system, but conversely retard them. The observed inhibition of the acoustic chemical process in a low-frequency field was estimated quantitatively.
91-93