Auto-oscillation of surface tension

Abstract

Long-time auto-oscillation of the surface tension can evolve when in an aqueous system a diethyl phthalate droplet is placed under the free water surface. The experimental conditions for development of surface tension auto-oscillations are described. Based on a theoretical analysis the mechanism of these auto-oscillations is proposed. The mechanism of the auto-oscillations results from a switching between diffusion and convection transfer of diethyl phthalate in the solution. A periodic Marangoni flow on the water surface resulting from a surface layer instability is discussed. The solubility of the amphiphile in the water and its surface activity are the main characteristics that determine the system behavior.

Electrochemical Properties of the Composites Synthesized From Polyaniline and Modified MWCNT

“…In order to obtain modified MWCNTs, the prepared mixture was stirred during 30 min and filtrated with distilled water and acetonitrile to remove residual sodium hypophosphite and NT. The modified MWCNTs were dried in the furnace at the pressure of 2 kPa and constant temperature of 298 K for ~20 h. Chemical reduction of NO 2 groups in the modified MWCNTs (1.23 g of each) was carried out by the solution of metallic zinc (2 g) in hydrochloric acid (8.5 ml) [12]. The obtained mixture was distilled during ~5 h and then filtered to remove residual hydrochloric acid.…”

Spontaneous Oscillation Mechanism by Simultaneous Time-resolved Measurements of Interfacial Tensions of Both the Donor/Membrane and Membrane/Acceptor Phases

“…Because there are several parameters that can influence the intensity of Marangoni convection, it is effective to evaluate the intensity using a combined dimensionless Marangoni number, Ma, in the form: 35,36 Ma h…”

Chemical Oscillation with Periodic Adsorption and Desorption of Surfactant Ions at a Water/Nitrobenzene Interface

“…4 Chemical oscillations at a liquid/liquid interface have also been drawing attention from researchers in terms of not only the nonlinear chemistry but also for studies of biomimetic system. Since Dupeyrat and Nakache 5 first reported the electrochemical potential oscillation at the water/nitrobenzene interface in the 1970's, many kinds of chemical oscillation systems, not only water/oil two-phase systems 5-11 but also water/oil/water threephase systems 12-28 or gas/liquid interfaces, [29][30][31][32] have been developed and extensively investigated.Recently, we found a new-type interfacial oscillatory phenomenon with periodic adsorption and desorption of sodium alkyl sulfate at a water/nitrobenzene interface. [23][24][25][26] As previously reported in other interfacial oscillations, our system also shows an oscillation of electrical potential between the aqueous phase and the oil.…”

“…4 Chemical oscillations at a liquid/liquid interface have also been drawing attention from researchers in terms of not only the nonlinear chemistry but also for studies of biomimetic system. Since Dupeyrat and Nakache 5 first reported the electrochemical potential oscillation at the water/nitrobenzene interface in the 1970's, many kinds of chemical oscillation systems, not only water/oil two-phase systems 5-11 but also water/oil/water threephase systems 12-28 or gas/liquid interfaces, [29][30][31][32] have been developed and extensively investigated.…”