Theory of depletion-induced phase transition from chiral smectic- A twisted ribbons to semi-infinite flat membranes.
Phys Rev E Stat Nonlin Soft Matter Phys
; 82(2 Pt 1): 021701, 2010 Aug.
Article
en En
| MEDLINE
| ID: mdl-20866826
ABSTRACT
We consider a theoretical model for the chiral smectic A twisted ribbons observed in assemblies of fd viruses condensed by depletion forces. The depletion interaction is modeled by an edge energy assumed to be proportional to the depletant polymer in solution. Our model is based on the Helfrich energy for surface bending and the de Gennes model of chiral smectic A liquid crystals with twist penetration at the edge. We consider two variants of this model, one with the conventional Helfrich Gaussian curvature term, and a second with saddle-splay energy. A mean field analysis of both models yields a first-order phase transition between ribbons and semi-infinite flat membranes as the edge energy is varied. The phase transition line and tilt angle profile are found to be nearly identical for the two models; the pitch of the ribbon, however, does show some differences. Our model yields good qualitative agreement with experimental observations if the sign of the Gaussian curvature or saddle-splay modulus is chosen to favor negative Gaussian curvature.
Buscar en Google
Colección:
01-internacional
Banco de datos:
MEDLINE
Tipo de estudio:
Qualitative_research
Idioma:
En
Revista:
Phys Rev E Stat Nonlin Soft Matter Phys
Asunto de la revista:
BIOFISICA
/
FISIOLOGIA
Año:
2010
Tipo del documento:
Article
País de afiliación:
Estados Unidos