Anomalous viscous retardation of a mechanical wave at percolation threshold

Abstract

We study the mean transit time needed for a mechanical shock to propagate through a random depleted lattice of freely-rotating elastic springs in a viscous medium at the central-force percolation threshold. This problem is the exact mechanical counterpart of anomalous diffusion. We show that the mean transit time for a pulse to cross a lattice of size L, scales as ∝ L2+θ' through a transfer-matrix analysis

Interaction and structuration of membrane-binding and membrane-excluding colloidal particles in lamellar phases

“…Membranes interact through different mechanisms: attractive van der Waals forces, repulsive hydration forces at very short separations, screened electrostatic forces, and the so-called Helfrich long-range repulsion arising from the loss of entropy associated with the confinement of the transverse membrane fluctuations [18]. The latter may dominate for membranes with weak bending rigidities, i.e., typically for surfactant systems [19]. There may also be attractive fluctuation-induced interactions originating from counterion correlations [20].…”

Crumpling and second sound in lyotropic lamellar phases

“…France 51 (1990) Lyotropic smectics [1] are lamellar phases consisting of stacks of regularly spaced fluctuating fluid membranes separated by a background fluid of oil (or of water). The separation between membranes can be as large as hundreds or even thousands of angstroms [2][3][4][5][6][7][8][9][10]. The Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphys:019900051010093300 membranes consist of bilayers of surfactant molecules, possibly enclosing a thin layer of water (or oil).…”