All the membranes are simulated at 6 different temperatures: 350, 330, 310, 290, 270, and 250K. The simulation lengths of different membrane systems are listed in Table . All the simulations are performed using NPT ensemble. Nose-Hoover thermostat with a coupling constant of 0.5 ps is used for temperature coupling. The pressure is controlled semiisotropically. Berendsen barostat is used for pressure coupling with a coupling constant of 5 ps. Periodic boundary conditions are applied in all three directions. Verlet leapfrog algorithm is used for solving the equations of motion at every 2 fs. Long-range electrostatic interactions are solved with the Particle Mesh Ewald (PME) summation method. The cut-off for the short-range Coulomb interactions and van der Waals interactions are set to 1.2 nm. The hydrogen containing bonds are constrained with lincs algorithm.