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Thermodynamically controlled multiphase separation of heterogeneous liquid crystal colloids
Han Tao1, Carlo Rigoni2, Hailong Li3
1Department of Bioproducts and Biosystems, Aalto University School of Chemical Engineering, Vuorimiehentie 1, 02510, Espoo, Finland.
Nature Communications
|August 29, 2023
Summary
This study explores complex phase separation in polymer and nanocellulose mixtures. Researchers achieved controlled multi-phase coexistence and hierarchical self-assembly into stratified films.
Area of Science:
- Materials Science
- Physical Chemistry
- Colloid Science
Background:
- Phase separation is a fundamental process in creating complex materials.
- Controlling simultaneous liquid-liquid and liquid crystal phase transitions is challenging.
Purpose of the Study:
- To develop heterogeneous colloidal suspensions exhibiting coupled liquid-liquid and liquid crystal phase separations.
- To investigate the control of phase behavior via thermodynamics and kinetics.
- To explore hierarchical self-assembly into functional films.
Main Methods:
- Fabrication of heterogeneous colloidal suspensions with semiflexible polymers and rigid nanocellulose.
- Thermodynamic and kinetic control of multiphase separation.
- Characterization of phase coexistence and self-assembly processes.
- Drying to form stratified cholesteric films.
Main Results:
- Achieved two-, three-, and four-phase coexistence with liquid crystal stackings.
- Demonstrated distinct kinetic pathways for polymer droplets and nanocellulose tactoids.
- Observed thermotropic polymer behavior within a lyotropic liquid crystal matrix.
- Created stratified cholesteric films with compartmentalized polymers and anisotropic micropores.
Conclusions:
- Multiphase separation and self-assembly can be precisely controlled in complex colloidal systems.
- Coupled phase transitions offer a route to advanced material fabrication.
- Hierarchical assembly leads to structured films with tunable properties.
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