Thermal switch of oscillation frequency in Belousov-Zhabotinsky liquid marbles.

Andrew Adamatzky,Thomas C Draper,Claire Fullarton,Ben De Lacy Costello,Neil Phillips

doi:10.1098/rsos.190078

Andrew Adamatzky, Thomas C Draper + Show 3 more

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https://doi.org/10.1098/rsos.190078

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Abstract

External control of oscillation dynamics in the Belousov–Zhabotinsky (BZ) reaction is important for many applications including encoding computing schemes. When considering the BZ reaction, there are limited studies dealing with thermal cycling, particularly cooling, for external control. Recently, liquid marbles (LMs) have been demonstrated as a means of confining the BZ reaction in a system containing a solid–liquid interface. BZ LMs were prepared by rolling 50 μl droplets in polyethylene (PE) powder. Oscillations of electrical potential differences within the marble were recorded by inserting a pair of electrodes through the LM powder coating into the BZ solution core. Electrical potential differences of up to 100 mV were observed with an average period of oscillation ca 44 s. BZ LMs were subsequently frozen to −1°C to observe changes in the frequency of electrical potential oscillations. The frequency of oscillations reduced upon freezing to 11 mHz cf. 23 mHz at ambient temperature. The oscillation frequency of the frozen BZ LM returned to 23 mHz upon warming to ambient temperature. Several cycles of frequency fluctuations were able to be achieved.

Highlights

Space–time dynamics of oxidation wavefronts, including target waves, spiral waves, localized wave-fragments and combinations of these, in a non-stirred Belousov–Zhabotinsky (BZ) medium [1,2] have been used to implement information processing since seminal papers by Kuhnert and co-workers [3,4]
While most of BZ computing devices use the presence of a wavefront in a selected locus of space as a manifestation of logical TRUE, there is a body of works on information coding with frequencies of oscillations
Period of oscillations increases from 28 s in intact liquid marbles (LMs) to 162 s in cooled-down LM

Summary

Introduction

Space–time dynamics of oxidation wavefronts, including target waves, spiral waves, localized wave-fragments and combinations of these, in a non-stirred Belousov–Zhabotinsky (BZ) medium [1,2] have been used to implement information processing since seminal papers by Kuhnert and co-workers [3,4]. Examples include image processing and memory [5], diodes [6], geometrically constrained logical gates [7], controllers. While most of BZ computing devices use the presence of a wavefront in a selected locus of space as a manifestation of logical TRUE, there is a body of works on information coding with frequencies of oscillations. Other results in BZ frequency-based information processing include frequency transformation with a passive barrier [18], frequency band filter [19] and memory [20]. Using frequencies is in line with current developments in oscillatory logic [21], fuzzy logic [11], oscillatory associated memory [22] and computing in arrays of coupled oscillators [23,24]. Frequencies of oscillations in BZ media will be the focus of this paper

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