Electrocapillary phenomena

A new technique based on electrocapillary phenomena at partially immersed solid metal electrodes has been developed by Jin-Hua et al. 146,147 jhe involves the detection of the rise of a solution... 

A. N. Frumkin, Electrocapillary Phenomena and Electrode Potentials (in Russ.), Odessa, 1919. 

Erumkin, A. N., Electrocapillary phenomena and electrode potentials [in Russian], dissertation, Commercial Publishers, Odessa, Ukraine, 1919. 

Every interface is more or less electrically charged, unless special care is exercised experimentally [26]. The energy of the system containing the interface hence depends on its electrical state. The thermodynamics of interfaces that explicitly takes account of the contribution of the phase-boundary potential is called the thermodynamics of electrocapillarity [27]. Thermodynamic treatments of the electrocapillary phenomena at the electrode solution interface have been generalized to the polarized as well as nonpolarized liquid liquid interface by Kakiuchi [28] and further by Markin and Volkov [29]. We summarize the essential idea of the electrocapillary equation, so far as it will be required in the following. The electrocapillary equation for a polarized liquid-liquid interface has the form... 

In addition to examining the surface structure, the STM may also be used as a transducer to monitor deformation associated with potential dependence of the surface stress and associated electrocapillary phenomena at solid electrodes. In this instance, the high z-sensitivity of the STM is used to follow the minute displacements of a surface, which is supported in a cantilever geometry [54,55],... 

A. Frumkin and A. Gorodetzkaya, Electrocapillary Phenomena with Amalgams, Z. Phys. Chem. 136 451 (1928). 

Electrocapillary phenomena have been studied for a long time the apparatus shown in Figure 7.22 is essentially that used by G. Lippmann in 1875 in his comprehensive studies of electrocapillarity. We do not examine either the experimental or the theoretical aspects of this system in great detail however, an interpretation of the results that is more quantitative than that just outlined qualitatively is possible with relatively little additional effort. 

Oct. 24,1895, Kishinev, Russia, now Chisinau, Moldova - May 27, 1976, Moscow, USSR, now Russia) After graduating from the technical college in Odessa (1912) and probation in StraCburg and Bern, he had taken an external degree of Novorossiisk University (1915). The early studies of Frumkin of -> electrocapillary phenomena at electrified interfaces (thesis, 1919) determined his future key directions in electrochemistry and colloid chemistry, continued later in Moscow in the Karpov Physico-chemical Institute (starting from 1922), Moscow University (starting from 1930 in 1933 he founded the Dept, of Electrochemistry there), and in the Institute of Colloid Chemistry and Electrochemistry later transformed into the Institute of Physical Chemistry. Finally, in 1958 Frumkin founded the Institute of Electrochemistry of the USSR Academy of Sciences, and headed it up to his death. 

Frumkin, Electrocapillary Phenomena and Electrode Potentials, Odessa, 1919. 

It should be noted that Eq. (4) is exactly the same as that derived for electro-osmotic volume flux on the basis of electrocapillary phenomena,... 

Information regarding the structure of EDL and the nature of some colloidal phenomena resulting from the interactions between ions and the interface can be obtained from the studies of electrocapillary phenomena, focusing at how the interfacial charge influences the surface tension. A complete description of electrocapillarity is given in courses in electrochemistry. Here we will only discuss the basic laws governing these phenomena that are important for understanding such colloidal phenomena as the adsorption of anionic and cationic surfactants, nucleation (see Chapter... 

Although this book significantly differs from the earlier Colloid Chemistry textbook, it nevertheless focuses on the specifics of educational and research work carried out at the Colloid Chemistry Division at the Chemistry Department of MSU. Many results presented in this book represent the art developed in the laboratories of the Colloid Chemistry Division, in the Laboratory of Physical-Chemical Mechanics (headed by E.D. Shchukin since 1967) of the Institute of Physical Chemistry of the Russian Academy of Science, and in other research institutions and industrial laboratories under the guidance of the authors and with their direct participation. Special attention is devoted in the book to the broad capabilities that the use of surfactants offers for controlling the properties and behavior of disperse systems and various materials due to the specific physico-chemical interactions taking place at interfaces. At the same time the authors made every effort to avoid duplication of material traditionally covered in textbooks on physical chemistry, electrochemistry, polymer chemistry, etc. These include adsorption from the gas phase on solid surfaces (by microporous adsorbents), the structure of the dense part of the electrical double layer, electrocapillary phenomena, specific properties of polymer colloids, and some other areas. 

Spatial gradients in surface tension may arise from a variety of causes, including spatial variations at the interface in temperature (Eq. 10.1.3), in surface concentrations of an impurity or additive (Eq. 10.1.4), or in electric charge or surface potential. The resulting flows are termed, respectively, thermocapillary flows, diffusocapillary flows, and electrocapillary flows. We shall limit our discussion of electrocapillary phenomena because of space restrictions but instead refer the reader to Levich (1962) and Newman (1991). 

ELECTROCAPILLARY PHENOMENA IN THE PRESENCE OF WEAK-CONDUCTOR LIQUIDS. 

ElectrocapUlary phenomenon refers to the modification of the interfacial tension by the presence of electrical charges. The first comprehensive investigations on electrocapillary phenomena were performed by Lippman, way back in 1875 [1]. In Lippman s experimental apparatus, the interfacial tension modulation due to electrical effects was observed through a capillary rise phenomenon and hence was later termed as electrocapillarity. A decisive advantage of electrocapillary actuation, in comparison to its thermal counterpart (i.e., the thermocapUlary effect, in which surface tension differentials are created by imposed temperature gradients), is the speed with which electrical potentials can be applied and regulated, with possible characteristic timescales of even less than a few milliseconds. Further, electrocapdlary-based microactuators consume much less power, as compared to the typical thermocapillary microdevices. 

Electrocapillary phenomena at the interface between two immiscible electrolyte solutions, which we will call the oil/water (O/W) interface for short, were studied first by Guastalla [1], then by Blank and Feig [2,3], Watanabe et al. [4, 5], Dupeyrat et al. [6, 7], Joos et al. [8,9], Gavach et al. [10-12], and Spumy [13]. Watanabe et al. applied the electrocapillary equations such as the Lippmann-Helmholtz equation to elucidate the double layer structure of the interface, whereas others [2,3,6,7] made a distinction between electrocapillarity and electroadsorption. Koryta et al. [14] have discussed the electric polarizability of the oil/water interface on the basis of the transfer Gibbs energies of ions from one solvent (the aqueous phase) to the other (the oil or organic phase). 

Electrowetting derives its roots from early observations of electrocapillary phenomena by Gabriel Lippmann in 1875, who noted variations in interfacial tension as an electric potential is applied between an electrolyte solution in direct contact with a metal, in this case, mercury. This culminated in the classical Lippmann equation ... 

During his time in the United States, Frumkin not only gave lectures to the staff and students of the University of Wisconsin but also toured many other universities. In this way he met many important American scientists and actively discussed their work with them. For example, at the University of Chicago, he visited the Laboratory of William Draper Harkins (December 28, 1873-March 7,1951) and also met with Arthur Holly Compton (September 10, 1892-March 15, 1962). In Princeton, he discussed the polymerization of unsaturated compotmds with Hugh Stott Taylor (6 February 1890-17 April 1974) and at Johns Hopkins University in Baltimore, he discussed the field of electrocapillary phenomena with Karl Ferdinand Herzfeld (February 24, 1892-June 3, 1978). In Philadelphia, he was delighted to meet George Borisovich Kistyakovsky (1900-1982), a chemist with Ukrainian-Jewish roots. 

Frumkin AN (1915) K thetnii elektrokapillamykh yavlenii (About the theory of electrocapillary phenomena). Zh Ross Fiz-Khim Obshch 643 154-157... 

Frumkin AN (1919) Elektrokapilliamye Yavleniya i Electrodnye Potentialy (Electrocapillary phenomena and electrode potentials). Dissertation, Odessa... 

Karpachev SV, Salnikov V, Bronin DI (1978) Electrocapillary phenomena at the interface of liquid metals and solid electrolyte. Dokl Akad Nauk SSSR (Rus) 243 966-968... 

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