Ostwald ripening
Small crystals dissolve
Ostwald ripening is a process in which larger particles or crystals grow at the expense of smaller ones in a solution or mixture.
Because smaller particles have higher surface energy, they dissolve more readily; the dissolved material then deposits onto larger, more stable particles.
The effect appears across many domains: ice cream coarsening in the freezer, emulsions separating over time, nanoparticles aggregating.
Named after the chemist Wilhelm Ostwald.
Becoming more crude
- nanoparticlesUltrafine material fragments
- colloidsSuspended particle systems
- emulsionsStable mixtures of immiscibles
- dispersionsDistributions throughout a substance
droplets · precipitates · aggregates · surfactants · stabilization · flocculation · sedimentation
Initial cluster formation
- crystallizationForming ordered solid structure
- facetingCutting angled surfaces
- latticeOpenwork of crossed strips
- dendriticBranching like a tree
polycrystalline · habit · microstructure · annealing · recrystallization
Becoming more crude
- dissolutionBreaking up completely
- diffusionPassive molecular spreading
- recrystallizationPurification through dissolving and reforming
- concentration gradientDifference in solute density
Work-extractable energy measure
- supersaturationExceeding dissolution equilibrium limits
- equilibriumState of balance
- driving forcePower behind movement
- spontaneityActing without forethought
Powder consolidation by heating
- ceramicsHardened clay objects
- metallurgyScience of extracting metals
- geological formationsNatural earth structures
- cloud dropletsMinute airborne water spheres
coarsening
Becoming more crude
- nanoparticlesUltrafine material fragments
- colloidsSuspended particle systems
- emulsionsStable mixtures of immiscibles
dispersions · droplets · precipitates · aggregates · surfactants · stabilization · flocculation · sedimentation
nucleation
Initial cluster formation
- crystallizationForming ordered solid structure
- facetingCutting angled surfaces
- latticeOpenwork of crossed strips
dendritic · polycrystalline · habit · microstructure · annealing · recrystallization
coarsening
Becoming more crude
- dissolutionBreaking up completely
- diffusionPassive molecular spreading
- recrystallizationPurification through dissolving and reforming
free energy
Work-extractable energy measure
- supersaturationExceeding dissolution equilibrium limits
- equilibriumState of balance
- driving forcePower behind movement
sintering
Powder consolidation by heating
- ceramicsHardened clay objects
- metallurgyScience of extracting metals
- geological formationsNatural earth structures
- crystallizationcrystal growth, nucleation, crystal structure, seed crystal, seed crystals
- colloidscolloid, aerosol, dispersion, emulsion, gel
- nucleationseed crystal