Properties of Wave Propagation in a Gel-type Belousov–Zhabothinsky Reaction under Micro-gravity

Hanke, Wolfgang; Sieber, Michaela; Spencer, Patrick Jack; Schwertner, Jürgen; Lima, Vera Maura Fernandes de

doi:10.1007/s12217-008-9072-x

Cited by 8 publications

(6 citation statements)

References 23 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In previous experiments (Nagypal et al 1986;Fujieda et al 1997Fujieda et al , 2002Wiedemann et al 2002;Hanke et al 2009) it has been shown that wave propagation in BZsystems is depending on gravity as well in fluid as in gel systems. This interaction can be attributed to diffusion, convection and buoyancy going on in such systems at different degrees.…”

Section: Discussionmentioning

confidence: 95%

“…1a) and than in the A-300. Some more details of a similar set-up have been published previously (Hanke et al 2009). The experiment was switched on after the airplane had reached its cruising altitude, typically about 30 to 60 min after filling the chambers.…”

Section: Methodsmentioning

confidence: 99%

“…Consequently, after it had been shown already that waves in BZ-reactions interfere with gravity (Nagypal et al 1986;Fujieda et al 1997Fujieda et al , 2002Wiedemann et al 2002;Hanke et al 2009), we now did a series of such experiments.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Gravitational Influence on an Oscillating Chemical Reaction

Klink

Hanke

Lima³

2011

Microgravity Sci. Technol.

Self Cite

View full text Add to dashboard Cite

Pattern formation, oscillations and wave propagation as processes in excitable media can be controlled by small external forces including gravity. The Belousov-Zhabothinsky (BZ) reaction is possibly the best studied system and exhibits temporal as well as spatial patterns. Wave propagation in BZ systems already has been shown to depend on gravity, due to interactions with diffusion and convection. In a stirred bulk BZ system stable oscillations exist in the absence of diffusion, sedimentation, buoyancy and convection with a period in the minute range. In parabolic flight missions such a system can be investigated under gravity conditions changing between 1 g, 1.8 g and μ-g just on this timescale. Here we have found that the temporal pattern formation of an oscillating BZ reaction locks to the period of the gravity changes but is also destabilized due to the partially stochastic nature of the gravity changes. This points out to a gravity dependence of chemical rate constants as given in a formal description of the BZ-system. The BZ-reaction is the perfect system for such studies and serves as a model for selforganization and pattern formation, also in biological systems. The possibility to study the lack of gravity or changes in gravity destabilizing self-organization and pattern formation is of major interest to identify the underlying mechanisms.

show abstract

Section: Discussionmentioning

confidence: 95%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Gravitational Influence on an Oscillating Chemical Reaction

Klink

Hanke

Lima³

2011

Microgravity Sci. Technol.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Chemical waves in BZ gels have been widely studied in recent decades. − It was found that these waves can be regulated via asymmetry, and chemical oscillations in heterogeneous BZ gels can be controlled via mechanical strain . In addition, BZ gels can sense external mechanical forces to trigger chemical waves …”

Section: Introductionmentioning

confidence: 99%

Capillarity-Induced Propagation Reversal of Chemical Waves in a Self-oscillating Gel

Wang

Gao

et al. 2020

J. Phys. Chem. A

View full text Add to dashboard Cite

In a self-oscillating gel, unidirectional chemical waves generated by the Belousov−Zhabotinsky reaction can drive locomotion, which results from the difference between the push and pull forces in the wavefront and waveback, respectively. In a narrow tube, such a gel is subject not only to the asymmetric force engendered by the propagation of the chemical waves but also to additional forces originating from the capillary effect in the polymer skeleton. The ends of a self-oscillating gel in a tube are squeezed unequally during unidirectional motion, causing new waves of higher frequency and ultimately giving rise to reversal of the direction of chemical wave propagation. This peculiar phenomenon of a self-oscillating gel in a narrow glass tube results in a nonmonotonic evolution of the gel locomotion velocity.

show abstract

“…Many other examples of excitable media exist in nature, including wild fires [3], certain living tissues (e.g. the heart [4], esophagus [5], intestine [6] and nerves [7]), chemical reactions [8,9], and more [10]. However, a man-made artificial excitable medium has never before been created.…”

Section: Introductionmentioning

confidence: 99%

A Bio-inspired Excitable Cardiac Cell Membrane from Electroactive Polymers: Ion Transport Studies

Moored

View full text Add to dashboard Cite

The heart is an incredibly efficient biological pump, which contracts as a whole from the coordinated effort of millions of excitable cells called cardiac myocytes. These cells are considered excitable since they possess the ability to respond to a threshold activation signal, but only if sufficient time has passed and they have recovered from their previous excitation. Excitable cells also have the capacity to propagate an activation signal to their neighboring cells, and collectively are referred to as an excitable medium. Numerous examples of excitable media exist in nature, including the heart, forest fires, the intestine, nerves, and certain kinds of chemical reactions. Engineered artificial excitable media, however, have never been developed before.The long-term goal of this project, therefore, is to develop the first such artificial excitable medium from an array of artificial excitable cells, called gel-cells. The conceptual design of the gel-cell consists of a thin electroactive ion-gating membrane (polypyrrole), sandwiched between two layers of hydrated polymer (hydrogel) loaded with different concentrations of potassium chloride (KCl aq ) electrolytes. The voltage controlled artificial membrane initially confines ions to the upper chamber of the gelcell, and releases them upon membrane opening into the lower chamber, a process similar to membrane activation in cardiac myocytes. Potassium sensing electrodes embedded throughout the gel-cell provide feedback on the location and concentration of ions within the gel-cell, becoming markers for its activation. The scope of the research presented here was to construct the biomimetic cell membrane portion of the gel-cell, and study ion transport through its assembly.First, the electrochemical response of polypyrrole (PPy) was characterized via cyclic voltammetry, and its membrane morphology and thickness were observed via scanning electron microscopy. Experimentally obtained membrane thickness values were then compared to model predictions, which were subsequently improved by updating membrane density and structure assumptions. Hydrogel pore size approximations were correlated to equilibrium water content calculations, and KCl aq concentrations were quantified using electrochemical impedance spectroscopy. Time-resolved KCl aq flux experiments were performed on PPy membranes in solution, providing real-time concentration profiles of KCl aq as it passes through the membrane. From the parameter space tested, the optimal membrane preparation and gating potentials were selected which produced the highest flux rates. Time-lapse flux experiments (providing piece-wise concentration profiles for KCl aq ) were then performed on PPy membranes in both solution and hydrogel. Ion transport through two nearly identical membranes produced under different deposition conditions (PPy a and PPy b ) were compared in solution. The slightly denser and thicker membrane (PPy b ) produced nearly an order of magnitude higher flux rates than PPy a , suggesting that an active comp...

show abstract

Properties of Wave Propagation in a Gel-type Belousov–Zhabothinsky Reaction under Micro-gravity

Cited by 8 publications

References 23 publications

Gravitational Influence on an Oscillating Chemical Reaction

Gravitational Influence on an Oscillating Chemical Reaction

Capillarity-Induced Propagation Reversal of Chemical Waves in a Self-oscillating Gel

A Bio-inspired Excitable Cardiac Cell Membrane from Electroactive Polymers: Ion Transport Studies

Contact Info

Product

Resources

About