Anomalous elasticity of an ordered lamellar liquid foam

We investigate experimentally the linear viscoelastic properties of a lamel lar liquid foam as a function of the cell size and spatial organisation, Th e system consists of multilamellar vesicles generated by a simple shear flo w on a lyotropic lamellar phase. The vesicles can be prepared either in an amorphous or a spatially ordered state. Their size is easily tunable ill th e range R = 0.5-15 mum Whereas the shear modulus of the amorphous lamellar foam is alike that of usual liquid foams or concentrated emulsions and scal es linearly with 1/R, the elastic modulus of the ordered foam is almost ind ependent of the cell size. This result probably the first describing the el asticity of an ordered foam-like system remains unexplained.