Investigation of the mid-infrared emission of a floating water bridge

Abstract

We report on the infrared emission of aqueous bridges under the application of high dc voltage (‘floating water bridge’) over the range between 400 and 2500 cm−1 (4.0–10.3 µm). Comparison with bulk water of the same temperature reveals an additional broad peak at ∼2200 cm−1 as well as water vapour emission lines. Two complementary explanations are presented for the broad peak: first, a cooperative proton transfer comprising an orientational motion along the direction of conduction is suggested. Second, the electrolysis-less current flow is explained by a proton/defect-proton band mechanism, which is in line with the cooperative proton transfer. The water vapour emissions occur due to collision ionization of space charges with micro- and nano-droplets which are electrosprayed from the liquid/gas interface.

The Preparation of Electrohydrodynamic Bridges from Polar Dielectric Liquids

“…Unlike electrosprays, EHD bridges in polar dielectric liquids dissipate energy in the form of both thermal as well as non-thermal infrared (IR) radiation 44 . Thermographic recording of liquid bridges (Figures 7-10) is a useful tool for examining surface flow dynamics as well as for quantifying the in operando IR active distribution of energy.…”

“…The later concept is not supported by a small angle X-ray scattering study 47 while the concept of hindered rotation (i.e. librations) is supported from infrared emission spectra 44 . The preferential flow direction in EHD liquid bridges arises from changes in the auto-dissociation kinetics.…”

“…These differences in energy relaxation dynamics strongly indicate that the water bridge and bulk water differ on a molecular scale. Furthermore, research on the infrared emission of a floating water bridge revealed a non-thermal feature which could be due to a transition from an excited state to the ground state of a proton conduction band 44 . Another more recent Raman study reported that in DC water bridges there is a radial distribution in the spectra which is indicative of relative difference in the local pH between the core and outer shell of the bridge 45 .…”

“…They permit the exploration of the interaction of bulk and surface forces with externally applied electric fields. They open the opportunity to examine new means of mixing different liquids 37 ; changing chemical reaction kinetics 52 ; proton transport 44,45 ; and examining the response of biological systems to such conditions 53 . In addition these bridges allow direct access to the liquid surface without any physically subtending structures which has already yielded new spectroscopic information on the dynamics in liquid water 28 and hints not only at the existence of an electrically controlled state switch whereby new bulk properties emerge 31 but at the potential to examine liquid-liquid phase transitions 54 through an entirely new method.…”

Floating and flying ferrofluid bridges induced by external magnetic fields

“…The study of this phenomenon was revived by Fuchs et al 2 in 2007. Thereafter, a number of research works [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] have been devoted to the floating water bridges between the deionized water in two containers induced by the high voltages applied to the deionized water. However, the interpretations to the origin of the floating water bridges are different at present stage, 3 for example, dielectric tension, 4 surface tension, 5 or both.…”