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Hiding in Plain View: Colloidal Self-Assembly from Polydisperse Populations.
Bernard Cabane1, Joaquim Li2, Franck Artzner3
1LCMD, CNRS UMR 8231, ESPCI, 10 rue Vauquelin, 75231 Paris Cedex 05, France.
Physical Review Letters
|June 4, 2016
Summary
Colloidal silica dispersions with broad size distributions unexpectedly form multiple crystal structures. This fractional crystallization reveals insights into designing self-assembling materials from polydisperse particles.
Area of Science:
- Materials Science
- Colloid Science
- Crystallography
Background:
- Colloidal dispersions are model systems for studying phase transitions.
- Achieving complex crystal structures typically requires monodisperse particles.
Purpose of the Study:
- To investigate the self-assembly behavior of polydisperse colloidal silica.
- To explore the formation of multiple crystalline phases in such systems.
Main Methods:
- Small-angle X-ray scattering (SAXS) experiments were conducted.
- Aqueous dispersions of colloidal silica with 8 nm size and 14% polydispersity were analyzed.
- Varying volume fractions were studied.
Main Results:
- Silica particles segregated to form distinct colloidal crystals.
- Fractional crystallization and coexistence of multiple phases (bcc, Laves AB_{2}, liquid) were observed.
- Complex structures formed from a polydisperse population.
Conclusions:
- Intermediate-range interparticle forces enable complex self-assembly in polydisperse systems.
- These findings offer a pathway for bottom-up design of self-assembling colloidal crystals.
- Fractional crystallization is achievable with broad size distributions.
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