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Nonclassical Crystallization Causes Dendritic and Band-Like Microscale Patterns in Inorganic Precipitates
Jéssica A Nogueira1, Bruno C Batista1, Maggie A Cooper1
1Department of Chemistry and Biochemistry, Florida State University, Tallahassee, FL 32306-4390, USA.
Angewandte Chemie (International Ed. in English)
|July 18, 2023
Summary
Self-organization in chemical gardens creates hierarchical patterns. Nanoparticles attach to precipitate membranes, forming bands that move against the flow, driven by particle concentration dynamics.
Area of Science:
- Materials Science
- Chemical Engineering
- Complex Systems
Background:
- Chemical gardens exhibit self-organization, forming complex precipitate structures.
- Hierarchical pattern formation occurs from atomic to macroscopic scales.
Purpose of the Study:
- Investigate thin walls of chemical gardens using microfluidic devices.
- Analyze light-scattering patterns and nanoparticle behavior in Ni(OH)2 membranes.
Main Methods:
- Utilized microfluidic devices to create linear Ni(OH)2 precipitate membranes.
- Observed light-scattering patterns (spots, dendrites, bands).
- Employed scanning electron microscopy (SEM) to analyze membrane composition.
Main Results:
- Identified distinct light-scattering patterns: disorganized spots, dendrites, and parallel bands.
- Observed bands tilted with respect to the membrane axis, with spacing increasing with flow rate.
- SEM revealed bands composed of submicron particles embedded in denser material, originating from the reactant stream.
Conclusions:
- Dendrites and bands form via attachment of solution-borne nanoparticles.
- Bands arise from upstream-moving particle-aggregation zones.
- The speed-wavelength dependence and flow-opposing motion are linked to particle concentration recovery dynamics.
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