Recognition of spatiotemporal patterns of the periodically precipitating 2D reaction-diffusion system by determination of precise band location: Implications on the Matalon-Packter law

Abstract

Recently focus of studies on the periodic precipitation in gels is shifting from evaluation of its spatio-temporal characteristics of the self-organized patterns to that of as a novel and viable method of synthesis of hierarchical monodispersed micro and nanomaterials in a single reactor. One of the parameters that profoundly affect the morphology, shape, size, and self-organization in the chemical systems is the supersaturation of the participating species. The Matalon-Packter (MP) law correlates the effect of the concentration of invading electrolytes to the spatial patterning in the Liesegang system. Although concentration and supersaturation have quantitative relations, the implications of supersaturation on the spatial arrangement of the band are not entirely understood. The present paper deals with studies on the periodically precipitating Co(OH)₂ in agar gel with respect to supersaturation of the participating reactants during the pattern formation. Varying inner and outer electrolytes concentrations were employed to determine spatial trends. Pattern image analysis was used to determine the precise location of the Liesegang bands. The supersaturation values showed a decreasing trend as the diffusion progressed outward. The present study led to the correlation between the supersaturation and the spacing coefficient.