| Langmuir monomolecular layers, formed by amphiphilic molecules at liquid air interfaces and containing a fraction of chiral molecules, are theoretically investigated. These monolayers can be brought out of thermal equilibrium by applying a gradient of small molecules across the interface, resulting in the leakage flow. In experiments recently performed by Tabe and Yokoyama wave patterns similar to target pattern were observed [1]. A new theoretical description is introduced for this nonequilibrium soft matter system, taking into account the changes of the tilt of chiral molecules. This is an extension to previous theoretical studies considering the splay coupling between the concentration field and the orientation [2,3]. Complex wave behavior like multi-armed rotating spirals an target pattern has been found in numerical simulations. Our model provides a theoretical description for the formation of coxexisting spirals and target pattern from arbitrary initial conditions, as observed in the experiments. Close to the transition to the untilted condensed phase the splay coupling may give rise to the reproduction of topological defects. 1. Y. Tabe and H. Yokoyama, Nat. Mater. 2, 806 (2003) 2. T. Shibata and A. S. Mikhailov, Europhys. Lett. 73, 463 (2006) 3. T. Shibata and A. S. Mikhailov, Chaos 16, 037108 (2006) |
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