Control of spontaneous spiral formation in a zwitterionic micellar medium

Rossi, Federico; Varsalona, R.; Marchettini, Nadia; Liveri, Maria Liria Turco

doi:10.1039/c1sm05439b

Cited by 9 publications

(10 citation statements)

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“…As the reaction proceeds, the production of Br 2 saturates S and can actively return to participate in the oscillatory mechanism. Similar properties of the BZ medium have been recently reported by Rossi et al, 25,26 who found that a zwitterionic surfactant (N-tetradecyl-N,N-dimethylamine oxide, C 14 DMAO) can form a charge transfer complex with Br 2 , thus acting as the sequestrating species S used in the present theoretical model (the value of the rate constant k 10 for the kinetic step 5 is inspired to this system). Due to the interaction between C 14 DMAO and Br 2 , an unusual oxidized induction period appears in the ferroin-catalyzed BZ reaction, whose duration increases with the surfactant concentration (typically in the range 0.003−0.008 M).…”

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confidence: 82%

“…In order to show that the interplay between a phase and a target wave can effectively represent a driving mechanism for the spontaneous nucleation of spirals in a real system with a quasi-two-dimension geometry, we performed experiments with the BZ−C 14 DMAO system which, as mentioned above, has been successfully introduced as an experimental example where a kinetic interaction of the type described by the reaction step 5 takes place. 25,26 As extensively discussed in ref 26, by varying the concentrations of the chemicals in solution, specifically [C 14 DMAO] and [NaBr], we can control to a certain extent the transition of target waves to spirals. Figure 5a illustrates the generation of two counter rotating spirals from a circular wave when [C 14 DMAO] = 5 × 10 −3 .…”

Section: ■ Experimental Sectionmentioning

confidence: 99%

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A Novel Mechanism for in Situ Nucleation of Spirals Controlled by the Interplay between Phase Fronts and Reaction–Diffusion Waves in an Oscillatory Medium

Budroni

Rossi

2015

J. Phys. Chem. C

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Understanding the transition from planar fronts, trigger waves, or solitary waves to spirals in excitable media has attracted increasing interest in the past few decades, mainly because of its relevance for biological and medical applications. In this paper, we introduce a new mechanism for the formation of rotating spiral waves based on the collision between a phase reduction front and trigger waves propagating in the oscillatory Belousov−Zhabotinsky (BZ) medium. The phase reduction front is triggered by imposing a heterogeneous spatial gradient of a chemical agent S able to temporarily sequester an inhibitory species of the oscillatory mechanism. This determines an initial oxidized transient over the whole reactor and, successively, a phase desynchronization by which the system recovers the excitable condition. The resulting reduction front can induce and control the transition from phase to trigger waves, whose properties depend upon the concentration profile of S along the spatial coordinate. By means of a numerical approach, we show that smooth gradients of the species S favor the formation of stacking waves with short characteristic wavelengths and the adaptation of the velocity of this cluster of pulses to that of the leading reduction front. Front-back annihilation between the reduction front and an incoming pulse may occur when the concentration profile of S has a steep gradient along the spatial domain. Experimental evidence of this mechanism as a possible source for spiral formation is shown in a quasi-two-dimensional geometry by using the BZ oscillator including the zwitterionic surfactant tetradecyl dimethylammonium oxide (C 14 DMAO). By segregating the inhibitor Br 2 , the micelles cause the onset of an oxidized induction period which vanishes after a few minutes through the propagation of a reduction phase front originated from an anisotropic spatial distribution of the surfactant C 14 DMAO. The reduction front gives a complex interplay with following target waves, including front−back collision. The spontaneous break of symmetry from target to spirals is controlled here by tuning the concentration of the surfactant or the alternative inhibitor species Br − .

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confidence: 82%

Section: ■ Experimental Sectionmentioning

confidence: 99%

A Novel Mechanism for in Situ Nucleation of Spirals Controlled by the Interplay between Phase Fronts and Reaction–Diffusion Waves in an Oscillatory Medium

Budroni

Rossi

2015

J. Phys. Chem. C

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“…2. Act as a catalyst in nucleophilic, dephosphorylation, photocatalytic oxidation and Belousov-Zhabotinsy reaction (Bunton et al, 1987(Bunton et al, , 1989Marcì et al, 2003;Rossi et al, 2008Rossi et al, , 2011.…”

Section: -[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate (Chaps)mentioning

confidence: 99%

Properties and applications of amphoteric surfactant: A concise review

Sarkar

Pal

Rakshit

et al. 2021

J Surfact & Detergents

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Amphoteric surfactants have long hydrophobic hydrocarbon chain and hydrophilic positive as well as negative charged center connected with each other by a spacer group. Thus, this type of surfactant maintains overall charged neutrality. The properties of amphoteric surfactants depend primarily on the length of the hydrophobic hydrocarbon chain, the number of methylene segments in the spacer, the positive and negative charged groups, and their relative position. The ionic activity of amphoteric surfactants is influenced according to the pH value of the solvent. They display cationic behavior below the isoelectric points and anionic behavior at a higher pH. They take the shape of zwitterions in the area of the isoelectric point. In fact, amphoteric surfactants can be parted into pH‐sensitive and pH‐insensitive surfactants. The pH‐insensitive surfactants stay as zwitterionic form irrespective of the pH of the solution. This surfactant has some unique features because of its precise molecular structure as follows: high water solubility, high surface activities, a wide isoelectric range, low critical micelle concentration (CMC), high foam stability, low toxicity, low irritating, excellent biodegradability, bioactivity, interface change, and so on. Because of these special characteristics, amphoteric surfactants have been immensely interested in many applications in the scientific community, including cosmetics, chromatography, enhanced oil recovery, electrochemistry, nanoscience, polymer chemistry, and waste water treatment. This review aims to study about amphoteric surfactants, which have only one hydrophobic hydrocarbon tail and two oppositely charged hydrophilic headgroups connected with each other by a spacer group and its properties, applications in various academics and industrial fields.

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“…Experimentally, we introduce sodium dodecyl sulphate (SDS) anionic surfactant in the BZ medium and vary its concentration above the critical micelle concentration (CMC) to increase the solution viscosity. SDS was found to slightly alter the kinetics of the BZ reaction, without changing the oscillation mechanism and without introducing new dynamical features 37 , conversely, for example, to the case of the zwitterionic surfactant N-tetradecyl-N,N-dimethylamine oxide that was found to cause an induction period prior the onset of regular oscillations [38][39][40] . Therefore, the use of SDS impacts mainly the viscosity of the solution that, in turn, affects the onset of natural convection.…”

Section: Introductionmentioning

confidence: 97%

Control of chemical chaos through medium viscosity in a batch ferroin-catalysed Belousov–Zhabotinsky reaction

Budroni

Calabrese

Miele

et al. 2017

Phys. Chem. Chem. Phys.

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In this paper we show that the active interplay of nonlinear kinetics and transport phenomena in a chemical oscillator can be exploited to induce and control chaos. To this aim we use as a model system the ferroin-catalysed Belousov-Zhabotinsky (BZ) oscillating reaction, which is known to evolve to characteristic chaotic transient dynamics when carried out under batch and unstirred conditions. In particular, chemical chaos was found to appear and disappear by following a Ruelle-Takens-Newhouse (RTN) scenario. Here we use medium viscosity as a bifurcation parameter to tune the reaction-diffusion-convection (RDC) interplay and force the reaction in a specific sequence of dynamical regimes: either (i) periodic → quasi-periodic → chaotic or (ii) periodic → quasi-periodic or (iii) only periodic. The medium viscosity can be set by adding different amounts of surfactant (sodium dodecyl sulphate), known to have a little impact on the reaction mechanism, above its critical micelle concentration. Experimental results are supported by means of numerical simulations of a RDC model, which combines self-sustained oscillations to the related chemically-induced buoyancy convection.

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Control of spontaneous spiral formation in a zwitterionic micellar medium

Cited by 9 publications

References 50 publications

A Novel Mechanism for in Situ Nucleation of Spirals Controlled by the Interplay between Phase Fronts and Reaction–Diffusion Waves in an Oscillatory Medium

A Novel Mechanism for in Situ Nucleation of Spirals Controlled by the Interplay between Phase Fronts and Reaction–Diffusion Waves in an Oscillatory Medium

Properties and applications of amphoteric surfactant: A concise review

Control of chemical chaos through medium viscosity in a batch ferroin-catalysed Belousov–Zhabotinsky reaction

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