Here, the formation of periodic precipitation (Liesegang bands) from hybrid (organic-inorganic) components is reported, namely ZIF-8, ZIF-67, and their mixed metal derivatives. The spacing and width laws that characterize the Liesegang system are determined and the resulting pattern is exploited to crystal engineer various sizes and doping of the ZIF material. Several key parameters that govern the crystallization process of ZIF-8 are investigated in each band and the growth of the particles in each band is found to follow an Ostwald ripening mechanism.
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ACS Omega
October 2024
Department of Chemistry, American University of Beirut, PO Box 11-0236 Riad El Solh, Beirut 1107 2020, Lebanon.
Liesegang patterns present a display of parallel stripes of precipitate that arise from the interdiffusion of coprecipitate ions in a gel medium. The bands observed in rocks are typical analogies of this phenomenon, and their composition is not restricted to the banded deposition of a single mineral. We here extend the study to a three-precipitate system, wherein Co, Ni, and Cd cations are precipitated by the same anion (OH from NHOH) to form Co(OH), Ni(OH), and Cd(OH), respectively.
View Article and Find Full Text PDFPhys Chem Chem Phys
January 2023
The University of Western Ontario, London, Ontario, N6A 5B7, Canada.
Chemical waves that produce periodic patterns are common occurrences in nature. The underlying processes involved have been studied in many disciplines of science, but rarely reported in the chemistry of corrosion. In this study of carbon steel corrosion, iron oxide crystals are observed to deposit in concentric wave patterns or in discrete bands, known as Liesegang patterns.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
September 2022
AMOLF, Amsterdam 1098 XG, the Netherlands.
Straightforward manufacturing pathways toward large-scale, uniformly layered composites may enable the next generation of materials with advanced optical, thermal, and mechanical properties. Reaction-diffusion systems are attractive candidates to this aim, but while layered composites theoretically could spontaneously arise from reaction-diffusion, in practice randomly oriented patches separated by defects form, yielding nonuniformly patterned materials. A propagating reaction front can prevent such nonuniform patterning, as is the case for Liesegang processes, in which diffusion drives a reaction front to produce layered precipitation patterns.
View Article and Find Full Text PDFACS Omega
January 2022
Department of Chemistry and Applied Chemistry, Saga University, 1 Honjo, Saga 840-8502, Japan.
Shapes and patterns observed in internal organs and tissues are reproducibly and robustly produced over a long distance (up to millimeters in length). The most fundamental remaining question is how these long geometries of shape and pattern form arise from the genetic message. Recent studies have demonstrated that extracellular matrix (ECM) critically participates as a structural foundation on which cells can organize and communicate.
View Article and Find Full Text PDFLangmuir
July 2021
Post Graduate and Research Center, Department of Chemistry, S. P. Mandali's Sir Parashurambhau College, Tilak Road, Pune, Maharashtra 411 030, India.
In the present study, a method is described for precise determination of spatial characteristics of Liesegang bands formed by employing a classical 1D setup using a web-based free resource (https://www.ginifab.com/feeds/pms/color_picker_from_image.
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