Доклады Академии наукДоклады Академии наук0869-5652The Russian Academy of Sciences1548210.31857/S0869-56524872169-173Research ArticleStrong dependence of contact angle on pressureRusanovA. I.<p>Academician of the Russian Academy of Sciences</p>airusanov@mail.ruEsipovaN. E.nesipova@mail.ruSobolevV. D.airusanov@mail.ruFrumkin Institute of Physical Chemistry and Electrochemistry Russian Academy of SciencesSaint-Petersburg State University3107201948721691732807201928072019Copyright © 2019, Russian academy of sciences2019<p>Although the usual pressures typically only slightly affect the properties of condensed phases and their surface layers, in physical chemistry of surfaces, it was found a quantity, the contact angle on the three-phase contact line, that is very sensitive to pressure. In experiments with an air bubble in water stuck to a solid surface, an increase in hydrostatic pressure of less than doubled gave an increase in the contact angle of more than 10 if the angle itself was sufficient but less than 90. Сhanging the orientation of the liquid - gas surface. If the angle (no matter sharp or obtuse) is close to 90, the mobility of the three-phase contact line arises as an alternative way to achieve equilibrium. To explain these phenomena, a thermodynamic theory is formulated. It is shown that with a fixed line of three-phase contact, an increase in pressure in a liquid always causes an increase in the contact angle. At the same time, an increase in the hydrostatic pressure of water by two times is equivalent to an increase in the partial pressure of water vapor inside the bubble by a factor of seven.</p>wettinghydrophobicitycontact anglethree-phase contact lineсмачиваниегидрофобностьугол смачиваниялиния трёхфазного контакта[Русанов А. И. Фазовые равновесия и поверхностные явления. Л.: Химия, 1967.][Rusanov A. I. Phasengleichgewichte und Grenzflächenerscheinungen. B.: Akademie-Verlag, 1978.][Русанов А.И., Кочурова Н. Н., Хабаров В. Н. // ДАН. 1972. Т. 202. С. 304.][Хабаров В. Н., Кочурова Н. Н., Русанов А. И. // Коллоид. журн. 1975. Т. 37. С. 92.][Хабаров В. Н., Кочурова Н. Н., Русанов А. И. // Коллоид. журн. 1975. Т. 37. С. 407.][Хабаров В. Н., Кочурова Н. Н., Русанов А. И. // Коллоид. журн. 1976. Т. 38. С. 120.][Rusanov A. I. // Surf. Sci. Rept. 1996. V. 23. C. 173.][Русанов А.И. // Коллоид. журн. 1998. Т. 60. С. 815.][Дерягин Б. В., Чураев Н. В. Смачивающие пленки. М.: Наука, 1984.][Русанов А. И. // Коллоид. журн. 1966. Т. 28. С. 718.][Русанов А. И. // Коллоид. журн. 1967. Т. 29. С. 142.][Русанов А. И. // Коллоид. журн. 1967. Т. 29. С. 149, 237.][Eriksson J. C. // Surf. Sci. 1969. V. 14. P. 221.][Rusanov A. I. // J. Colloid Interface Sci. 1978. V. 63. P. 330.][Rusanov A. I. // Pure Appl. Chem. 1992. V. 64. P. 111.]