Shape anisotropy and Voids
  Numerical simulations on a 2-dimensional model system showed that voids are induced primarily due to shape anisotropy in binary mixtures of interacting disks. The results of such a simple model account for the key features seen in a variety of flux experiments using liposomes and biological membranes. 
Gauri R. Pradhan, Sagar A. Pandit, Anil D. Gangal, V. Sitaramam