https://doi.org/10.1140/epje/i2007-10218-0
Regular Article
Transport and crystallization of colloidal particles in a thin nematic cell
1
J. Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia
2
Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000, Ljubljana, Slovenia
* e-mail: igor.musevic@ijs.si
Received:
10
April
2007
Accepted:
7
August
2007
Published online:
20
September
2007
In a thin planar nematic cell, the application of an AC electric field induces a macroscopic transport of micrometer-sized colloidal particles along the nematic director. We have analyzed the dependence of particle velocities on the electric-field amplitude and frequency and found that it decreases exponentially with increasing frequency. Using specially designed electrodes we have observed that colloidal particles could be pumped and accelerated across the field-no-field interface, and measured the structural force and the corresponding potential, which is of the order of 10000 kBT for 4μm particles. We demonstrate that spatially periodic close-packed crystalline colloidal structures can be obtained, which are thermodinamically metastable for many days after turning off the electric field and slowly decay into linear chains. Above the nematic-isotropic phase transition, such crystalline structures are non-stable and decay in few minutes.
PACS: 82.70.Dd Colloids – / 81.16.Dn Self-assembly – / 83.80.Xz Liquid crystals: nematic, cholesteric, smectic, discotic, etc. –
© EDP Sciences, Società Italiana di Fisica and Springer-Verlag, 2007