Electric-Field-Induced Reversible Phase Transitions in Two-Dimensional Colloidal Crystals
Two-dimensional colloidal crystals confined within electric field traps on the surface of a dielectrophoretic cell undergo reversible phase transitions that depend on the strength of the applied AC electric field. At low field strengths, the particles adopt a two-dimensional hexagonal close-packed l...
| Publié dans: | Langmuir : the ACS journal of surfaces and colloids. - 1985. - 31(2015), 38 vom: 29. Sept., Seite 10411-7 |
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| Auteur principal: | |
| Autres auteurs: | , , , , |
| Format: | Article en ligne |
| Langue: | English |
| Publié: |
2015
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| Accès à la collection: | Langmuir : the ACS journal of surfaces and colloids |
| Sujets: | Journal Article |
| Résumé: | Two-dimensional colloidal crystals confined within electric field traps on the surface of a dielectrophoretic cell undergo reversible phase transitions that depend on the strength of the applied AC electric field. At low field strengths, the particles adopt a two-dimensional hexagonal close-packed lattice with p6m plane group symmetry and the maximum achievable packing fraction of φ = 0.91. Higher electric field strengths induce dipoles in the particles that provoke a phase transition to structures that depend on the number of particles confined in the trap. Whereas traps containing N = 24 particles transform to a square-packed lattice with p4m symmetry and φ = 0.79 is observed, traps of the same size containing N = 23 particles can also pack in a lattice with p2 symmetry and φ = 0.66. Traps with N = 21, 22, and 25 particles exhibit a mixture of packing structures, revealing the influence of lateral compressive forces, in addition to induced dipole interactions, in stabilizing loosely packed arrangements. These observations permit construction of a phase diagram based on adjustable parameters of electric field strength (0-750 V/cm) and particle number (N = 21-25) |
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| Description: | Date Completed 17.12.2015 Date Revised 29.09.2015 published: Print-Electronic Citation Status PubMed-not-MEDLINE |
| ISSN: | 1520-5827 |
| DOI: | 10.1021/acs.langmuir.5b03230 |