On the mechanism of nitrobenzene liquid membrane oscillators containing hexadecyltrimethylammonium bromide

Szpakowska, Maria; Czaplicka, Izabela; Nagy, O. B.

doi:10.1016/j.bpc.2005.11.004

Cited by 14 publications

(45 citation statements)

References 8 publications

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“…In line with these novel achievements, Szpakowska et al have also studied the oscillations in the CTAB-water/nitrobenzene or nitromethane/sucrose-water system [31][32][33]. The shape of oscillations strongly depended on the compound forming a liquid membrane and the surfactant dissolved in aqueous phase [11].…”

Section: Recent Developments In Liquid Membrane Oscillatorsmentioning

confidence: 92%

Liquid Membrane and Other Membrane Oscillators

Orlik

2012

Self-Organization in Electrochemical Systems II

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In complement to the hydrodynamic instabilities driven by surface tension gradients, enclosed in Sects. 5.4-5.7, we describe here the dynamics of the liquid-liquid interface, formed by two fluids of very limited miscibility, e.g., by water and 2-nitropropane. First reports on this type of dynamical systems have been published by Dupeyrat and Nakache [1,2], and later analogous studies were continued also by .A representative example of that type of the systems is the water-2-nitropropane system [3]. The key point is that each phase should contain the dissolved species that is significantly better soluble in the other phase. In this way the initial state of such system is far from equilibrium and the natural trend to decrease the free Gibbs energy is the flow of each dissolved species to the other phase. In the example described here, the aqueous phase contains initially the hexadecyltrimethylammonium bromide (or cetyltrimethylammonium bromide, CTAB) the large organic CTA + cation of which exhibits, due to its hydrophobicity, higher affinity to the organic phase. In turn, the phase of 2-nitropropane contains initially dissolved picric acid (HA), better soluble and also partly dissociating in water (pK a % 0.2).When these two phases are brought into contact, with the organic layer placed over the aqueous layer, the oppositely directed flows of CTAB and HPi begin. This transport is associated with subtle oscillations of various characteristics: pH of aqueous solution, interfacial potential drop (Fig. 6.1), and interfacial tension. The latter phenomena are easily detectable as visible oscillations of the meniscus at the interface of both liquids. It is interesting that under such non-equilibrium conditions the presence of surfactant (CTAB) does not depress the surface tension gradients, but on the contrary, it is responsible for their periodic temporal variations.Yoshikawa and Matsubara [3] have proposed the mechanism of these oscillatory phenomena. First, one should note that CTA + cations in both phases form micelles above certain critical CTA + concentrations. Those micelles exhibit inverted M. Orlik, Self-Organization in Electrochemical Systems II, Monographs in Electrochemistry,

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Section: Recent Developments In Liquid Membrane Oscillatorsmentioning

confidence: 92%

Liquid Membrane and Other Membrane Oscillators

Orlik

2012

Self-Organization in Electrochemical Systems II

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“…A considerable number of studies have examined oscillatory liquid-membrane systems with different chemical compositions and geometries. 7,8,[43][44][45][46][47][48][49][50][51][52][53][54][55][56][57][58][59] In all of the cases studied, the surfactants in the donor phase were considered to be dissolved in the membrane phase and to transfer into the acceptor phase, but the origin of the electric potential oscillations remains controversial. 43,46,47 One issue in previous studies, which has caused controversy, is that interfacial tension measurements at the donor/membrane and the membrane/acceptor interfaces have never been made simultaneously.…”

Section: Spontaneous Chemical Oscillation In the Donor/membrane/accepmentioning

confidence: 99%

Quasi-elastic Laser Scattering for Measuring Inhomogeneous Interfacial Tension in Non-equilibrium Phenomena with Convective Flows

2014

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An inhomogeneous distribution of interfacial tension can induce different types of non-equilibrium spontaneous motion at the interface by convective flow, or by the solutal Marangoni effect. Several applications of the quasi-elastic laser scattering (QELS) method used to study these effects are presented here. The relationship between the interfacial tension and the non-equilibrium phenomena has been verified experimentally for each application. In a water/nitrobenzene oscillatory system with continuous surfactant addition to the interface, the local adsorption of surfactants at the interface has been demonstrated and shown to be strongly related to the presence of electrolytes. In a donor/membrane/acceptor system, the dual-beam QELS method shows that surfactant adsorption at the membrane/acceptor interface is responsible for oscillations in the electric potential. The differences in the adsorption/desorption behavior of metal complex catalysts between air/liquid and liquid/liquid interfaces were considered in the propagating chemical waves of the BelousovZhabotinsky reaction. We successfully measured the distribution of interfacial tension around a self-propelled camphor boat and an alcohol droplet floating on an aqueous phase, and compared the mechanisms of their motion.

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“…In this system, fairly regular oscillations of rather high amplitude (250-350 mV) appear after a certain induction period [2,11,12]. This oscillator was investigated in view of molecular recognition [2,4,11,17] and to establish the mechanism of oscillations of electric potential difference between the aqueous phases [7][8][9][10][11][12][13][14][15][16].…”

Section: Introductionmentioning

confidence: 99%

“…At the beginning, the system is far from equilibrium. It has been demonstrated that it can attain equilibrium in an oscillatory manner [1][2][3][4][5][6][7][8][9][10][11][12][13][14], as shown by the periodical changes of the electric potential difference between the donor and acceptor aqueous phases.…”

Section: Introductionmentioning

confidence: 99%