Dynamic scaling in phase separation kinetics for quasi-two-dimensional membranes

Brian A. Camley, Frank L. H. Brown
2011 Journal of Chemical Physics  
We consider the dynamics of phase separation in lipid bilayer membranes, modeled as flat twodimensional liquid sheets within a bulk fluid, both in the creeping flow approximation. We present scaling arguments that suggest asymptotic coarsening in these systems is characterized by a length scale R(t) ∼ t 1/2 for critical (bicontinuous) phase separation and R(t) ∼t 1/3 for off-critical concentrations (droplet morphology). In this limit, the bulk fluid is the primary source of dissipation. We also
more » ... issipation. We also address these questions with continuum stochastic hydrodynamic simulations. We see evidence of scaling violation in critical phase separation, where isolated circular domains coarsen slower than elongated ones. However, we also find a region of apparent scaling where R(t) ∼ t 1/2 is observed. This appears to be due to the competition of thermal and hydrodynamic effects. We argue that the diversity of scaling exponents measured in experiment and prior simulations can in part be attributed to certain measurements lying outside the asymptotic long-length-scale regime, and provide a framework to help understand these results. We also discuss a few simple generalizations to confined membranes and membranes in which inertia is relevant.
doi:10.1063/1.3662131 pmid:22168731 fatcat:fxgxtkwdrzcxzokbqfkfnbcr5y