  Amphiphilic lipid bilayers modify the friction properties of the surfaces on
top of which they are deposited. In particular, the measured sliding friction
coefficient is significantly reduced compared with the native surface. We
investigate in this work the friction properties of a numerical coarse-grained
model of DSPC (1,2-distearoyl-sn-glycero-3-phosphocholine) lipid bilayer
subject to longitudinal shear. The interleaflet friction coefficient is
obtained from out-of-equilibrium pulling and relaxation simulations. In
particular, we gain access to the transient viscoelastic response of a sheared
bilayer. The bilayer mechanical response is found to depend significantly on
the membrane physical state, with evidence in favor of a linear response regime
in the fluid but not in the gel region.
