Inducement by directional fields of rotational and translational phase ordering in polymer liquid-crystals

The effects of aligning fields on models of polymer liquid crystals were simulated using the dissipative particle dynamics method. Exposing a liquid crystal of rod-like particles to a directional field causes a stabilization of the phases with orientational order, shifts the isotropic-nematic and ne...

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Bibliographic Details
Published in:The Journal of chemical physics 2013-04, Vol.138 (15), p.154904-154904
Main Authors: AlSunaidi, A, den Otter, W K, Clarke, J H R
Format: Article
Language:English
Subjects:
Alignment
Computer simulation
Dissipation
Liquid crystals
Order disorder
Phase shift
Phase transformations
Separation
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Summary:The effects of aligning fields on models of polymer liquid crystals were simulated using the dissipative particle dynamics method. Exposing a liquid crystal of rod-like particles to a directional field causes a stabilization of the phases with orientational order, shifts the isotropic-nematic and nematic-smectic-A phase transitions to higher temperatures, makes the transitions continuous beyond a critical field strength, and induces weak para-nematic alignment in the zero-field isotropic phase. The interplay of liquid-crystalline ordering, microphase separation, and an alignment field endows the diblock and triblock copolymers studied here with rich phase behavior. The simulations suggest that field-induced orientational ordering can give rise to positional ordering. Reversely, positional ordering resulting from rod-coil demixing may be accompanied by orientational ordering, which is enhanced by external fields. For highly asymmetric rod-coil copolymers, the microphase separation pattern formed by the rigid segments can be altered by an aligning field.
ISSN:0021-9606
1089-7690
DOI:10.1063/1.4798462