“…The two different types of domain that form in a binary amphiphile mixture may be in the liquid and gel phases respectively, [9][10][11][12] or may both be in the liquid phase, [12][13][14][15] albeit with different degrees of internal order in the amphiphile chains. 4,12 Domain formation can be controlled by a variety of factors, including the difference in chain length between the two amphiphile species, 4,9,16,17 the lateral tension in the bilayer 11,18 and the presence of a third species, such as a protein or peptide, 1,[19][20][21][22] cholesterol, 4,10,12,20 ionised calcium 23 or a ceramide. 24 In this paper, we focus on a system in which two of these factors interact, and use a coarse-grained mean-eld model to investigate how adding oil to a bilayer composed of two amphiphiles of different chain lengths affects the structure of the membrane around the boundary between two liquid domains.…”