Volume 81, Number 6, March 2008
Article Number 66001
Number of page(s) 6
Section Condensed Matter: Structural, Mechanical and Thermal Properties
Published online 22 February 2008
EPL, 81 (2008) 66001
DOI: 10.1209/0295-5075/81/66001

Topological defects in bicontinuous phases

P. Pieranski

Laboratoire de Physique des Solides, Université Paris-Sud - Bât. 510, 91405 Orsay, France

received 13 December 2007; accepted in final form 23 January 2008; published March 2008
published online 22 February 2008

It is shown that in balanced bicontinuous cubic lyotropic crystals two types of dislocations are possible. The first, trivial type of dislocations preserves the orientability of the surfactant bilayer. Dislocations of the second, Möbius type make the bilayer non-orientable. Upon melting of the cubic phase into the sponge phase, crystal order is destroyed but Möbius dislocations persist by virtue of topological continuity as disorientation: a new kind of topological defects which, by definition, alter the orientability of the bilayer.

61.30.Jf - Defects in liquid crystals.
61.30.St - Lyotropic phases.
61.72.Bb - Theories and models of crystal defects.

© EPLA 2008