where γ is the strain, Lx is the length of the system along x without compression, Ly is the system length in y, and bi is a set of coefficients described by Hu et al. . For each bilayer we carried out 5 production runs of 8 µs each, the errors reported are the standard errors considering the 5 independent samples. At the time of simulation, GROMACS did not support the c-rescale barostat for fully anisotropic pressure coupling, and so the Parinello-Rahman barostat 188 was used instead.